TESTING FOR SUGAR.

Any person, provided with one of the hydrometers mentioned, can easily ascertain the percentage of sugar contained in any must with tolerable accuracy, providing the grapes from which it is pressed are ripe; for if they are green, and contain an undue amount of acid, the density will be materially affected by that. There is no occasion, however, for making wine from green grapes in this State.

Fig. 2.

Hydrometer-Jar.

In addition to the hydrometer, it is necessary to be provided with a thermometer with which to ascertain the temperature of the must. Besides the hydrometer and the thermometer, the only other article necessary is a glass tube closed at the bottom and provided with a foot, so that it will stand upright, called the hydrometer-jar. ([Fig. 2].) This jar should have a diameter a little greater than that of the bulb of the hydrometer, and must be of such a height that the latter instrument will stand upright and float freely in it, when filled with a liquid. In the absence of the hydrometer-jar, an empty fruit jar, or a tall tin cup or can will answer its purpose. In performing the operation, see that all the articles used are perfectly clean, more particularly the hydrometer, for anything that would slightly affect its weight would render the result of the test useless. Having taken this precaution, press the juice from a small quantity of grapes and strain it through a cloth, and pour sufficient into the hydrometer-jar, that when the hydrometer is plunged into it, it will just bring the level of the liquid to the upper edge of the vessel, or to such a height that the figure on the stem can easily be read. Now place the thermometer in the must and ascertain its temperature, for the instruments are intended to be used at a certain degree of heat, although three or four degrees variation either way will not materially affect the result. Baumé’s instrument, as originally constructed, was graduated for a temperature of 10° Reamur, which corresponds with 54½° F.; but as constructed now-a-days, is generally graduated for a temperature of 58° or 60° F.; and Balling’s and Oechsle’s for a temperature of 63½° F. Some of Balling’s instruments sold in the market are graduated for 62° F. If it is found that the temperature is above or below the degree indicated, it may be lowered by cooling, or raised by warming, till about the right temperature is reached. Then the hydrometer, being clean, should be taken by the stem at the top and gradually lowered into the must until it floats. Press it down slightly with the finger and let it come to equilibrium, being careful that there is not a drop of water on the stem above the surface of the liquid, nor a bubble of air below. On looking at the stem where it meets the surface, it will be seen that the liquid there curves upwards around the instrument, and that the top of this curve marks one degree higher than the general surface. If the reading is taken from the point marked by the top of the curve (the figures reading downwards), add one degree, or in other words, ascertain the mark on the stem corresponding to the general surface of the liquid. If Balling’s scale is used, the number at this mark shows the percentage of sugar which the must contains; if Baumé’s is used, consult Table II or III, and opposite this number will be found the corresponding per cent. of sugar. If Oechsle’s scale is used, find from Table I or II the specific gravity and the corresponding sugar per cent. Under Table I instructions will be found for reading Oechsle’s scale. If Baumé’s instrument is used, and a table is not at hand, multiply the observed figure by 1.8, and the product will be nearly the per cent. of sugar.

Correction for Temperature.—It is known that a sugar solution or a must expands as the temperature increases, and contracts as it diminishes; and nice experiments have been performed to show the amount of dilatation and contraction at different temperatures, and the consequent variation in the specific gravity of the liquid, but there is considerable difference in the results of the researches of different authors, and it would seem that further experiments are necessary; but a rule may be deduced which may be used instead of changing the temperature of the must to make it correspond with that for which the instrument is graduated, and although not strictly correct, is sufficient for our purpose; and that is to add one-half per cent. to the sugar per cent. indicated by the hydrometer for every 15° F. above the standard temperature, and subtract ½ per cent. for every 15° below. For instance, if Baumé’s instrument shows 22½ per cent. of sugar at 75° F., the actual strength is 23 per cent., and it would mark that at 60°. If the same instrument shows 23½ per cent. at 45° F., the real strength is 23 per cent. In using Balling’s scale graduated at 63½° F., the 15° in our example would make 78½° for the first supposed case, and 48½° for the second.

In most cases the variation in temperature will be so little that it may be disregarded; but if the test is made soon after the grapes have been exposed to a hot sun, the must may show a temperature of 90° or 95° F., and it would indicate one per cent. less than its real sugar strength. But the temperature would go below the freezing point of water before the must would mark one per cent. too much.

As the must contains a small quantity of acids and extractive matter which affect its density, some authors recommend that from one-tenth to one-fifteenth of the figures indicating the density by Baumé should be deducted, calling the remainder sugar, and this is about equivalent to deducting one for every twelve per cent. of sugar. But if the grapes are ripe and the must is strained, for all practical purposes all of the solid matter may be called sugar, considering that we make a pretty liberal allowance of sugar for one per cent. of alcohol. Fresh must should always be taken for the purpose of testing for sugar, for as alcohol is much lighter than water, if fermentation has commenced, it will be impossible to ascertain the amount of sugar by means of the hydrometer.

Sugar and Alcohol.—It will be shown in the chapter on fermentation that, in actual practice, it takes about two per cent. of sugar, as indicated by the hydrometer, to produce one per cent. by volume of alcohol; therefore, divide the percentage of sugar contained in the must, as shown by the hydrometer, by two, and the quotient is approximately the per cent. of alcohol which will be contained in the wine after complete fermentation.

Alcohol in Wine.—A good, saleable dry wine ought to contain from eleven to twelve or thirteen per cent. of alcohol; and to produce such a wine the must should indicate from 22 to 26 per cent. of sugar by the hydrometer. A wine which is soon to be consumed at home does not require that degree of strength necessary for shipment abroad and for keeping, and may contain only ten per cent. of alcohol, and even less, and be found a very palatable drink, and less “heady” than that of a higher degree of spirit. And a wine may contain as much as 14 per cent. of spirit, and be very acceptable to the wine merchant for mixing with weaker wines.

A must which does not contain more than 24 per cent. of sugar per hydrometer, if properly managed, will complete its fermentation, and if it does not contain less than 22 per cent., will make a good, sound, shipping wine, which will keep in almost any climate. Mr. Crabb, a well known wine maker of Oakville, in this State, writes me that such a must will ferment dry in six days, but that if it contains more than 24 per cent. of sugar, fermentation is likely to be arrested by the amount of alcohol, when it amounts to 12 per cent. This gentleman is an intelligent viniculturist and a practical man, and it would be safe to follow his advice. Mr. Arpad Haraszthy, who is noted in this connection, in his lecture on fermentation before the convention of wine growers, held at San Francisco in September, 1882, indicated 22 per cent. as a proper degree of sugar in the must; and it is reported that the wine makers of Los Angeles county, in fixing the prices of grapes in 1882, adopted 23 per cent. as the standard. Undoubtedly the fermentation will be finished sooner, and will be less troublesome, if the must contains sugar within the limits of 22 and 24 per cent., than if allowed to go beyond. (See [Maturity].) If it should go to 26 per cent. and beyond, the chances are that the fermentation will be incomplete, and that a portion of the sugar will remain in the wine, which will cause it to ferment when exposed to changes of temperature; it may become milk sour, and there will be danger of rapid deterioration. From which it follows that, except for making sweet wines, the grapes should be gathered before they develop much more than 24 per cent. of sugar. Supposing, however, that picking commences as soon as the must shows 22 per cent., sufficient force should be employed to finish before it goes beyond the limit indicated. For the writer has seen grapes gathered at the beginning of the season and made into wine which showed 11 per cent. of alcohol, when the wine made from grapes of the same vineyard, gathered too late, either on account of lack of pickers or of fermenting tanks, contained 14.5 per cent., and was still sweet.

CHAPTER III.
SUGARING AND WATERING MUST.

Sugaring.—As early as 1776, Macquer, in France, found that by adding sugar to the must of green grapes, he could make wine; and since his time many authors, notably Chaptal, Gall, and Petiot, have recommended the addition of sugar to the must of bad years when the grapes did not ripen; and had the practice been limited to the addition of sufficient sugar of good quality to a must which was deficient in that respect, but little harm would have been done. The next step, however, was to take the must of partly ripe grapes which contained an undue quantity of acid, and reduce it by the addition of water till the acid corresponded in quantity to that contained in a must of ripe grapes, and then to add sufficient sugar to bring it up again to the necessary degree of sweetness. This may be permissible in those countries where in some years the grapes do not ripen, and in order to make a drinkable wine, water to reduce the acid, and sugar to give sweetness, must be added. But this did not satisfy the greed of the artificial wine makers; they found, so they say, that they could press the juice from the grapes, ferment it by itself, then add to the marc water and sugar enough to bring it back to its original quantity and sugar strength, draw off the artificial juice slightly colored by the skins, and repeat the operation, and so make three and four times the quantity of wine that could otherwise be made, and all good wine.

It was thought that wine making in Europe would be revolutionized, and untold wealth would pour into the coffers of the wine makers. It was found, however, that cane sugar was too expensive, but artificial glucose could be made from grain and potatoes at a very small cost, and by reason of its cheapness its use was forthwith recommended; and to such an extent was the matter carried, that one would suppose that in order to make good wine, it was only necessary to soak a few grape skins in a quantity of sweetened water and let it ferment!

The practice, however, to the extent mentioned, did not commend itself to sensible men, and wine making did not become revolutionized. Yet it was to some extent adopted, and the effect upon the wines of Burgundy is shown by Dubrunfaut in his work on Sucrage de Moûts. He says that starch-sugar (glucose) factories were established in Burgundy, and from 1825 to 1845, this material was used to strengthen the musts. But complaints arose in France and elsewhere against Burgundy wines; they had a new flavor, and unexpected changes in many respects had come over them. A congress of wine makers was held at Dijon in 1845, at which the abandonment of the use of glucose was decreed upon the report of a committee of merchants and proprietors of Beaune, which was in effect as follows: that the long extolled and generally practiced system of sugaring, and against which a reaction set in some years ago, ought to be completely abandoned, as being fatal (funeste) to Burgundy. He considers, however, as do some others who condemn the use of glucose, that the use of refined cane sugar is unobjectionable if used in small quantities and merely to fortify the must when it needs it. There are many authors, however, who speak highly of the wines produced by the addition of sugar and water to the skins after the juice has been drawn off, but it does not seem reasonable that a good wine can be made in that manner. If a good must contained only water, sugar, and acids, then there would be reason for believing that the wine so made would be good. But it is well known that many other ingredients enter into the composition of the juice of the grape which, in some unknown manner, have a very important influence upon the wine made from it. Attempts have been made to produce an artificial must, which is carrying the process but little farther than it is carried by some of the writers on the subject; but Mr. Boireau says that what is produced resembles cider rather than wine. He gives the following composition as approaching very nearly a must for common white wine:

Refined Sugar,25kilog.
Tincture of tannin,20gr.
Crystals of tartaric acid,500gr.
Gum arabic,1kilog.
Vine leaves and fresh twigs chopped,  5kilog.
Distilled or filtered water,1hectol.

The author last quoted is a practical man, and his opinion is valuable. He says, when the fermentation of this artificial must is most active, it has analogies with ordinary white wine, but it costs much more than the natural wine; and when its fermentation is complete, it has not a bad taste, and there is nothing hurtful in its composition, but that it has not the taste of white wine; and the only time when it has any analogy to white wine is during the tumultuous fermentation as already mentioned. Many attempts have been made to vary the formula, but without important results. Tolerably agreeable drinks are obtained, but they are not wine. M. Boussingault gives his experience in sugaring and watering must; and the wine produced lacked acid, color, astringency, and was very inferior to the wine first made from the pure juice; it lacked the fixed substances and aromatic principles. He says that some would prefer it to cider, but that it only differed from piquette in having a greater degree of alcohol.

To give even a summary of what has been written upon this subject would occupy a volume, but the results arrived at by the more intelligent modern writers and experimenters may be summed up as follows:

1. That good wine can be made only from the pure juice of the grape.

2. That in case the grapes do not ripen sufficiently to make a drinkable wine, water may be added to reduce the acid, and then sugar enough to bring it up to the average sugar strength; but in no case should any but the refined cane sugar be used; artificial glucose, never.

Nothing gained by adding Sugar.—Aside from the question of quality, it may not be amiss to add a few remarks for the benefit of intended wine makers who may have been led to believe, by mistaken authors, that the profits of wine making may be increased by adding sugar and water, and thereby augmenting the quantity. Assuming that it is permissible to use only refined sugar, it can easily be shown that it is as cheap, if not cheaper, to make wine from grapes than from sugar, as long as grapes can be bought for $30 per ton.

A gallon of dry wine of average specific gravity, containing 10 per cent. by weight, or 12.4 by volume, of alcohol, weighs about 8¼ pounds, and contains about .825 of a pound of pure alcohol. To produce a pound of alcohol requires about 2¼ lbs. of pure grape sugar, or 2.138 lbs. of pure cane sugar, in practice, according to the chapter on fermentation; so that to produce the .825 lbs. of alcohol in one gallon of wine, requires about 1.80 lbs. of pure cane sugar. But refined crystalized sugar is not pure sugar (anhydrous), as it contains about 10 per cent. of water; so, to make our 1.8 of pure sugar, requires 2 lbs. of ordinary refined sugar. At 10 cents per pound, which would be cheap for this market, it would cost 20 cents to make the must for a gallon of wine.

Supposing that a ton of grapes costs $30, and produces 150 gallons of wine, each gallon would cost 20 cents. So that there is nothing to be gained by adding sugar at 10 cents a pound, even if a ton of grapes costs $30 a ton, for the same facts would apply to every pound of sugar added to a must, as well as in the case supposed, where all the sugar was supplied.

Cost of Glucose Wine.—Supposing that artificial glucose contains 80 per cent. of pure (anhydrous) sugar, it would require 2⅓ lbs. to make our gallon of wine; and if it could be laid down here at 5 cents a pound, the gallon of wine would cost nearly 12 cents, and this would be equivalent to paying $18 a ton for grapes.

When we take into consideration that every pound of glucose and water added to a must will diminish the price of every gallon of wine produced, it is probable that but little, if anything, could be gained even by the use of this article; for the product will not bring the price of an honest wine, and in the long run will destroy the reputation of our wines, and reflect injury upon every wine maker in the State.

Experiment with Glucose.—Mr. Crabb, of Oakville, gave his experience with glucose in a paper read before the St. Helena Vinicultural Club, in July, 1882, as follows: I took three packages of equal size, one containing pure grape juice, the two others containing each equal parts of the same juice and glucose water, all showing 23 per cent. sugar by Balling’s saccharometer. The pure juice was dry in 15 days (the room being cold). One package of the mixture was dry in 30 days; the other continued in fermentation 60 days, both emitting a rank offensive odor during the process, arising from the amount of chalk and sulphuric acid required in its (glucose) manufacture. Racking at this time appeared to remove the greater part of the offensive odor, and in 30 days the wine was clear and bright enough to pass for a two-years’-old wine. I now thought it contained a very superior fining principle, and if a small enough quantity would answer the purpose, it might be a valuable acquisition. But this was its most favorable period; it had reached its zenith, and while the pure juice was now beginning to develop its vinous properties, the mixture commenced to deteriorate, becoming flat and insipid, as any grape juice would by being one-half water, and the sulphuric acid and chalk (sulphate of lime) developing a disagreeable after-taste. Notwithstanding that I have racked it again and fined it to a perfect condition, there is not the least improvement, and I believe as it becomes more dry with age, that the bitter, nauseous after-taste will become more and more pronounced, so that one glass of it will leave such a lasting impression on the palate as to never want any more; whereas, the package of pure juice is now vinous, sprightly, refreshing and inviting.

The use of Glucose condemned.—On the 16th day of July, 1881, the St. Helena Vinicultural Association adopted resolutions condemning in the strongest terms the use of glucose in the making of wine and brandy, and promising to expose all parties importing or receiving the substance by publishing their names, and pledging the Society to use all honorable means to prevent the adulteration of the product of our vineyards. The resolutions passed unanimously, and were published in the different newspapers. One man in the district, notwithstanding the warning, did cause to be shipped to him a quantity of glucose, and the President and Secretary of the Society published in several different newspapers, in December, 1881, over their own signatures, and in the name of the Association, a notice reciting the resolutions, and stating that a person (giving his name) “imported eighty barrels of grape sugar, made from corn, commonly called glucose, and used the same, or the greater part of it, in the manufacture of wine during the last vintage.”

We believe that this was an exceptional case, and that its use in this State has been exceedingly rare.

Watering.—Another question which has been a good deal discussed is, whether it is better to pick the grapes as soon as they develop sufficient sugar, or leave them on the vine till they develop an excess, and then reduce the must with water. Dr. Guyot having laid it down as a fundamental principle in wine making in France, that the grapes should be left on the vine as late as possible, and until they have reached the highest point of maturity, except, perhaps, in some of the most extreme southern portions, he is consistent in counseling the addition of water to the must. But the only reason given by him for it is that it is consonant with his principle previously stated. Du Breuil is also of the same opinion. Both are men of high authority, but it does not appear that either of them ever made wine in a warm climate, where the grapes would develop so much sugar as to require the addition of water, if left upon the vine as late as possible. We have, on the other hand, the testimony of Boireau, who, speaking on the subject, says that it is probable that the theoreticians who are in favor of the practice have never made wine of must too rich in sugar and of water. He says, it is true that the quantity is increased, and fermentation is complete, but that the wine so made is only fit for the still, will not keep and readily turns sour. The Greeks have followed this practice from time immemorial in the Archipelago, where he tasted their wine so made in 1865, and which they can keep with difficulty for one year, in spite of the addition of a large quantity of rosin, which they introduce during fermentation. And yet, these wines are not weak, having an average of 10½ to 11 per cent. of alcohol. He says that but few grapes give musts too rich in sugar, if they are gathered as soon as ripe; for even in viticultural countries situated farthest south, as the south of France, Spain, Italy, Greece, and Africa, the grape just ripe gives a must which does not exceed 14° Baumé, unless left on the vine until part of the water of vegetation has evaporated.

Having alluded to both sides of the question, it would seem to be a fair inference from the foregoing that the safest course would be, in a hot climate, to gather the grapes as soon as fairly ripe. This may easily be done, where each grape grower makes his own wine, and has immediate supervision of the picking, and has sufficient men to finish it with promptness. But in the case of large manufacturers who buy their grapes and cannot supervise or order the gathering in the numerous vineyards whose crops they purchase, it may sometimes be necessary, when the grapes come in overripe, and it is not desirable to make sweet wine, to add a small quantity of water to insure prompt and complete fermentation. When the necessity arises, great caution should be used, and the necessity should be avoided when possible.

CHAPTER IV.
STEMMING AND CRUSHING.

Diversity of Opinion on Stemming.—There is no subject connected with wine making upon which there is a greater difference of opinion than that of stemming. And it would seem that the diversity of practice is not always caused by the different conditions and exigencies of location, variety of grapes, etc.; but among the different wine makers in the same locality, some remove the stems, and others do not; from which Dr. Guyot infers that the practice cannot be classed among the essential principles governing vinification, but is a mere matter of detail, and that stemming may be practiced or omitted without materially affecting the wine. But Machard, a writer of the Jura, lays it down imperiously as one of the very essentials of good wine making that the grapes should be fermented with the stems, and calls stemming a pernicious practice.

Effect of Stemming.—All agree, however, that the stems, during fermentation, if not removed, yield tannin to the wine, and thereby give it astringency. It is also said to increase fermentation, by furnishing to the must additional germs of fermentation adhering to the stems, and perhaps acting also in a mechanical way, by presenting many salient points, and exposing a greater surface to the action of the ferment.[1] They also add a certain amount of acid to the wine, if green. It is evident that they increase the labor of pressing, by adding to the mass of marc.

Proper Practice.—If, therefore, by reason of the variety of grapes cultivated, or the soil, or situation, your wine is too soft, lacks life and astringency, ferment with all or a portion of the stems; but if your wine is rough, too astringent, it will be found beneficial to stem the grapes. If your grapes lack the fermentive principle, and fermentation is slow and incomplete, leave the grapes on the stem; and in the same way the fermentation will be assisted, if the grapes are overripe.

When the grapes are fermented with the stems, care must be taken that they do not remain too long in the vat, or the wine may acquire a bitter, disagreeable flavor, called by the French goût de râpe, or stem flavor, which is caused by the bitter principle contained therein, and which is dissolved out by maceration.

To Estimate Tannin.—A certain amount of tannin is necessary to the proper clearing of the wine, which is brought about by the tannin combining with albuminous matters, and they are then precipitated, and the wine may be drawn off, leaving them at the bottom of the cask. It is on the application of this well known principle that Maumené gives a very simple method of ascertaining whether the grapes should be stemmed or not. He says: First make a small quantity of wine without the stems, and add tannin, or, what is better, a decoction made by boiling a quantity of stems, and if sensible precipitation is produced, it is better to ferment with the stems, for tannin is wanting; but if the precipitation is not formed, the grapes should be stemmed.

Fig. 3.

Wooden Stemmer.

Stemmers.—This is usually effected in California by the use of the common hand stemmer, though some large establishments are using a stemmer run by steam or horse-power. The common stemmer consists of an oblong shallow box or frame, six or eight feet long by two wide, or any convenient size, and about six inches deep, with a coarse wire netting or grating stretched across the bottom. This grating is usually made of heavy galvanized iron wire, with ¾ inch or inch meshes. Instead of having the grating extend the whole length, a portion at one end may be floored with wood, upon which a box of grapes can be placed without injuring the grating. The only objection to this stemmer is that the grape juice comes in contact with the metal of the grating, and it is a well known fact that nearly, if not all, of the baser metals are corroded by the acids; it would be better to replace the wire with a wooden grating, as in France ([Fig. 3].).

How to Remove the Stems.—The grapes are dumped from the boxes directly into the stemmer, and the workman seizes as many as he can easily manage with both hands, and rubs and rolls them to and fro upon the wire grating, and the berries, as they are rubbed off, fall through the meshes, and the stems remain in the hand. The few grapes that may remain are removed by raising the mass of stems and forcibly throwing them two or three times upon the grating. Sometimes the stems, with the few grapes clinging to them, are turned over to another workman, who, with a hay fork, tosses them about upon another grating till all the berries are removed. The stemmer ought to be situated over the hopper of the crusher, so that the grapes will fall directly into it, as they are separated from the stems.

Crushing.—It is generally considered essential to crush the grapes whether stemmed or not, although in some special cases, to be hereafter noted, crushing is omitted.

Methods of Crushing.—It is well known that in Europe the grapes are usually crushed by being trodden with the feet of men, usually barefooted, but sometimes in wooden shoes, and many of the best writers of to-day are of the opinion that the wine is better when the grapes have been well trodden with the bare feet, for by thoroughly rubbing the skins and pounding them into a pulp without breaking the seeds, they think that more color and aroma are developed than can be obtained by simply crushing them, as in a machine, and afterwards fermenting. Although the practice of treading is the more common one in Europe, yet there are exceptions, and in some places the crushing is done by rollers and with satisfactory results. In California we are accustomed to regard the treading of grapes as an antiquated practice, and a relic of a past age, and it is almost universally discarded, being practiced only occasionally and by Europeans, who have not yet wholly fallen into our methods of practice. Those who are fastidious in this matter may rest assured, that if they will drink California wine, they run but very small risk of imbibing a liquid which a man has had his feet in.

Aerating the Must.—There seems to be some confusion on this subject, for some claim that the must is better exposed to the air, and prepared for fermentation, by treading. This may be true of treading in the vat during fermentation, but simply treading the grapes to crush them does not aerate the must as much as crushing with rollers, for in the latter case the juice falls through a considerable distance in a finely divided form, which thoroughly exposes it to the air.

Fig. 4.

Crusher.

Crushers.—The machine generally employed consists of two rollers made of wood, iron, or other suitable material, 6 or 8, or even more, inches in diameter, geared together so that they revolve in opposite directions and towards each other, and so that the grapes will be drawn between them from above. The rollers run near each other, but do not touch, so that the grapes will be crushed, and the seeds remain unbroken. It is operated by one man turning a crank, either attached to one of the rollers or to a pinion. [Figure 4] represents such a crusher, except that in the figure the rollers are open-work, instead of solid, as they should be. It is surmounted by a hopper which allows the grapes to fall between the rollers as they revolve, and the whole apparatus should be so placed that the pomace may fall into the fermenting vats, or be easily conveyed to them or to the press, accordingly as it is to be made into red or white wine.

Some stemmers have corrugated instead of plain rollers, but there is no advantage in this, and unless they are very nicely adjusted to the motion of the cog wheels, they may break the seeds, which is always considered injurious to the wine.

Rapidity of Operation.—Five men—one to handle the boxes of grapes, two to stem, standing on opposite sides of the stemmer, one to operate the crusher, and one to take the stems and remove the remaining grapes and to make himself generally useful—can stem and crush with these hand machines twenty tons of grapes per day, enough to make three thousand gallons of wine. And the work can be done much more rapidly by the use of the stemmer and crusher combined, which is to some extent used in the largest establishments.

Special Practice.—Boireau says that it has been observed that of the Médoc wines, those made without crushing the grapes have less color than those made from grapes of the same crop which have been crushed, but that they have a more refined and delicate taste (plus fins de goût), and that consequently many of the proprietors of the grands crûs of the Médoc in those years which are favorable to the maturity of the grape do not crush; they only do it in inferior years, when the grapes have not become sufficiently ripe, and when they fear that the wine may not have a suitable color. And in another place he tells us that in those grand wines which are intended to be bottled, a superabundance of tannin and its consequent roughness may be avoided by complete stemming, fermenting the whole berries, and by drawing from the fermenting vat at just the right time.

CHAPTER V.
FERMENTATION—ITS CAUSES.

It is with some hesitancy that I attempt to give a brief summary of the results of scientific investigation into this subject, for fear of going beyond the legitimate limits of a practical work, as this book is intended preëminently for practical men. But as the work would be incomplete without it, and as a knowledge of the general phenomena of fermentation, and of the different influences to which it is subject, are of vast importance to those who will intelligently apply their principles, I give the following as but a brief resumé, and will put it as plainly as the subject will permit. Most of the ideas given below are extracted from Schutzenberger’s work on fermentation.

There are several different kinds of Fermentation, as (1) vinous, alcoholic or spirituous fermentation; (2) mucous or viscous fermentation; (3) lactic fermentation; (4) ammoniacal fermentation; (5) butyric fermentation; (6) putrifaction; and (7) acetic fermentation, or fermentation by oxidation, and others.

Alcoholic Fermentation is that which sugar undergoes under the influence of the ferment or yeast; and it is now agreed that this ferment consists principally of an aggregation of living organisms, or an assemblage of microscopic cells.

The Yeast Plant.—Our author gives them the name of saccharomyces cerevisiæ, following those who consider it to be a species of fungus, and states that it is now very generally admitted that ferments are fungi, although by some they have been considered animal in their nature. These cells are round or oval, and are from .00031 to .00035 of an inch in their greatest diameter. “They are formed of a thin and elastic membrane of colorless cellulose, and of a protoplasm, also colorless, sometimes homogeneous, sometimes composed of small granulations.” The cells are separate or united two by two. When they are deposited in a fermentable liquid, as a sugar solution or a must, small prominences are seen to arise at one or rarely two points, the interior of which is filled with protoplasm from the mother cell; these prominences grow until they have attained the size of the original cell, when the base contracts, forming a kind of neck, and immediately they separate from the mother cell, and under favorable conditions one cell produces several generations, but by degrees it loses all its protoplasm, which at last unites in granules swimming in super-abundant cellular juice. The cell ceases to produce, and dies; the membrane is ruptured, and the granular contents are diffused in the liquid. In the manufacture of beer the fermentation is of two kinds: surface fermentation and sedimentary fermentation, depending upon a high or a low degree of heat. The surface saccharomyces develop more rapidly than the others, are larger, and they bud so rapidly that the cells which issue from each other do not separate, but remain attached, forming ramified chains of from six to twelve or more buds. The bubbles of rising gas have a greater hold on these chaplets than on single cells, which causes the newly formed yeast to rise to the surface during active fermentation. These organisms or fungi produce spores which are sown on the surface of fruits, and get into the juice by crushing, when they commence their reproduction by budding. So that the basis or cause of the phenomena which we call fermentation is the growth and reproduction of yeast or ferment, which is made up principally of the minute organisms just described.

Functions of Yeast.—Yeast is a living organism, belonging to the family of fungi, genus Saccharomyces, destitute of mycelium, capable of reproduction, like all the elementary fungi, by buds and spores. Its composition singularly resembles that of other vegetable tissues, and especially the plants of the same family. It does not differ essentially from other elementary cells, unprovided with chlorophyll.

Normal Conditions of the Life of Yeast.—The conditions which our author calls normal in the life-history of yeast, are those in which it develops itself and increases with the greatest activity and energy. They are of two orders, physical and chemical.

With respect to physical conditions, it is only necessary to notice the temperature. That most favorable to the nutrition of yeast, and that which is found advantageous to other cellular vegetable organisms, is between 25° C. and 35° C. (77° and 95° F.) Above and below these limits, the vital manifestations do not cease until we descend below 9° C. (48.2° F.), or rise above 60° C. (140° F.), the temperature at which albuminoid principles begin to coagulate.

With regard to the chemical conditions, our author says that the most favorable medium is that which contains the most appropriate nutritive elements. And as yeast contains water, mineral salts, especially potassium, magnesium, and calcium phosphates, therefore water and the alkaline and alkaline-earthy phosphates will be necessary. We find, besides, a great proportion of nitrogenous substances, either albuminous or otherwise; and therefore the food of yeast must contain nitrogen. It is supposed, however, that the cells are not directly nourished by albuminoids in the juices of fruits, the wort of beer, or yeast water, but by analogous compounds contained in them, which have the property of passing by osmose through the membranes; for the albuminoids themselves, it is said, cannot pass through. Pasteur has shown by his experiments, that mineral salts are absolutely necessary to the development and nutrition of the yeast cell; and Mayer follows him with details as follows: Preparations of iron, in small quantities, seem to have no influence; in larger proportions, they are injurious. Potassium phosphate is indispensable, and the absence of lime has little effect. Magnesium, on the contrary, appeared to be very useful, if not indispensable. The combinations of sodium present no material effects.

Sugar is one of the most important elements in the nourishment of the yeast cells, and Pasteur has shown that, in alcoholic fermentation, a part of the sugar is fixed in the yeast, in the state of cellulose or some analogous body, for, when the fermentation is completed, it is found that more yeast is present than at the commencement. Water is necessary, and the yeast cell manifests its activity, develops and is nourished within the limits of 40 and 80 per cent. of water, though yeast, dried with precaution, may regain its power when moistened. And the fact that a solution containing over 35 per cent. of sugar will not ferment, is explained on the theory that such a solution takes from the cells by osmose a sufficient quantity of water to lower their hydration below 40 per cent. The cells of the Saccharomyces cerevisiæ, introduced into a liquid medium, absorb oxygen with great rapidity, and develop a corresponding quantity of carbon dioxide. This constitutes respiration, comparable to that of animals. By careful experiments it has been shown that yeast breathes when placed in contact with dissolved oxygen, and the respiration is more active than that of fishes, and it plays as important a part in the life of those minute vegetable cells as in the higher forms of vegetable and animal life. Oxygen is furnished by atmospheric air, and fermentation is more rapid when a large surface of the liquid is exposed, and then the budding is more active.

Action of various Chemical and Physical Agents.—“It has long been known that certain chemical compounds, especially those which coagulate albuminous substances, and disorganize the tissues, or which, by their presence in sufficient quantities, are incompatible with life, are opposed to fermentation; such are the acids and alkalies in suitable proportions, silver nitrate, chlorine, iodine, the soluble iron, copper, and lead salts, tannin, phenol, creosote, chloroform, essence of mustard, alcohol when its strength is above 20 per cent., hydrocyanic and oxalic acids, even in very small quantities.

“An excess of neutral alkaline salts or sugar acts in the same manner, by diminishing in the interior of the cell the minimum quantity of water, which is necessary to the manifestation of its vital activity.

“The red mercury oxide, calomel, manganese peroxide, the alkaline sulphites and sulphates, the essences of turpentine and of lemon, etc., also interfere with, and destroy alcoholic fermentation.

“Phosphoric and arsenious acids are, on the contrary, inactive.”

Experiments have shown that sparks of electricity passing through yeast do not modify its power of changing cane sugar into glucose, nor its activity as an alcoholic ferment. Fermentation is slower in the dark, and also in a vacuum. Flour of sulphur did not sensibly affect fermentation, but the carbonic acid evolved contained sulphuretted hydrogen. Sulphurous acid, however, arrests fermentation. Yeast is always acid, but an addition of an excess of different acids arrests the decomposition of sugar. If one hundred times the amount of acid contained in the yeast is added, fermentation does not take place.

M. Dumas has shown the action of various salts on yeast, but the subject has little if any interest for the wine maker.

Viscous or Mannitic Fermentation is also excited, according to Pasteur, by special ferment acting on glucose, transforming it into a kind of gum or dextrin, mannite, and carbon dioxide. This ferment is also formed of small globules united as in a necklace, whose diameter varies from .000047 to .000055 of an inch. These globules, sown in a saccharine liquid containing nutritive nitrogenous matter and mineral substances, always give rise to viscous fermentation. One hundred parts of cane sugar give: mannite, 51.09; gum, 45.48; and carbon dioxide, 6.18. The liquids which are most apt to produce viscous fermentation can also undergo lactic and butyric fermentation, but in this case the organized forms of life which are developed in the liquid are of a different nature. The conditions of action necessary to these gummy and mannitic ferments are the same as those which suit alcoholic ferment. The most favorable temperature is 30° C. (86° F.) This fermentation is what gives rise to the disease of wines, called by the French la graisse, or ropiness. White wine is more subject to it than red, and it is generally due to the want of tannin. (See [Ropiness].)

Lactic Fermentation is the transformation which certain sugars, as sugar of milk and grape sugar, undergo, and by which they are changed into lactic acid. This takes place in the souring of milk. The most favorable temperature for it seems to be about 95° F. This also depends on a special ferment. Sugar solutions are also capable of butyric fermentation and putrefaction, and we generally see viscous, lactic, and butyric fermentation appear in succession.

Acetic Fermentation is to the wine maker and wine dealer, after alcoholic fermentation, the most important.

Fermentable matter and ferment are also concerned in it, but oxygen also is necessary.

It has long been known that the alcohol contained in fermented liquids, such as wine, beer, etc., will disappear under certain circumstances, and give place to vinegar or acetic acid, and that the air, or rather its oxygen, plays a part in this reaction.

To the chemist the reaction is simple, and is formulated thus:

Alcohol. Water. Acetic Acid.
C₂H₆O +O₂ =H₂O +C₂H₄O₂,

or the oxidation may take place by two reactions, with the production of an intermediate product, aldehyde:

Alcohol. Aldehyde.
C₂H₆O +O =H₂O +C₂H₄O,
Aldehyde. Acetic Acid.
C₂H₄O +O =C₂H₄O₂

According to Pasteur, the oxidation of alcohol is the consequence of the action of a ferment or cryptogam, Mycoderma aceti, and it makes its appearance on the surface of liquids, while in acetic fermentation, in the form of a continuous membrane, mother of vinegar, either wrinkled or smooth, which is generally formed of very minute elongated cells, whose greater diameter varies from .000059 to .000118 of an inch; these cells are united in chains, or in the form of curved rods. Multiplication seems to be effected by the transverse division of the fully developed cells. The conditions of nutrition are similar to those suitable to the alcoholic ferment, the hydro-carbon matter being supplied by dilute alcohol. It may, however, be supplemented by the acetic acid itself; for if the process is left too long to itself, the vinegar loses its strength by being consumed. The most favorable temperature is between 76° and 82° F.

Antiseptic agents, which arrest the development of beer yeast, act in the same manner on the Mycoderma aceti. Sulphurous acid is especially active in this manner; hence the use of the sulphur match in sulphuring wine casks.

There is another ferment, Mycoderma vini, or flowers of wine, which is found in wine and other alcoholic liquids exposed to the air when fermentation is over or has become languid, which resembles in many respects the acetic ferment. It has the power of producing alcoholic fermentation, and is supposed by some to be derived from the Saccharomyces. Like the Mycoderma aceti, it is developed on the surface of fermented alcoholic liquors, in the form of smooth or wrinkled films or membranes, but thicker and more compact. It grows with great rapidity, and it has been calculated that one cell would, in forty-eight hours, produce about 35,378 cells. These cells are of various forms, ovoid, ellipsoidal, and cylindrical, with rounded extremities. The ovoid cells have their greater diameter about .000236, and their smaller one, .000157 of an inch. The cylinders have their diameters .00047 × .000118 in. The nutritive principles are the same as those of the mother of vinegar: alcohol, salts and nitrogenous compounds. It also appears capable of utilizing for nutrition the secondary products of alcoholic fermentation, such as succinic acid and glycerine. Its development is most active between 61° and 86° F. (See [Sherry].)

Origin of Ferments.—In order to produce the different kinds of fermentation, the necessary ferment must be added, unless it is already contained in the fermentable matter or in the air. In the manufacture of beer and bread, yeast must be used; the other kinds of fermentation, except alcoholic, can generally be produced by the ferments or their spores furnished by the atmosphere; but Pasteur, in the course of his investigations, never produced alcoholic fermentation from spores found in the air. But the germs of the Saccharomyces cerevisiæ and of Mycoderma vini seem to be found only on the surface of fruits, and their stems.[2]

These different germs, however, are all found in the must of grapes, and in wine, and are ready to develop whenever favorable conditions offer themselves, and produce diseases in the wine. It is found that these germs are killed by raising the temperature of the liquid to 140° F., and hence the process of heating wines to preserve them (which see).

Leaving the germ theory of fermentation, we will pass to what is of more practical importance.

ALCOHOLIC FERMENTATION
IN WINE MAKING.

Vinous or Alcoholic Fermentation transforms the juice of the grape into wine, and, as already shown, is caused by the yeast or ferment, which finds its way into the must; and by this fermentation the sugar of the grape is changed principally into alcohol, and carbon dioxide, or carbonic acid gas. And in order to show the relations between the sugar and the alcohol produced, it is necessary to say something about the chemical constituents of each.

Sugar.—In general terms, cane sugar may be expressed by the chemical formula, C₁₂H₂₂O₁₁, or, in other words, one molecule contains 12 atoms of carbon, 22 of hydrogen, and 11 of oxygen.

And the general term glucose, or grape sugar, may be expressed by the formula C₆H₁₂O₁₆, or one molecule contains 6 atoms of carbon, 12 of hydrogen, and 6 of oxygen.

If, instead of using the word atoms, we use the word pounds, the chemical formula may be made clear to the unscientific. Taking the formula for cane sugar, already given, it simply means that 342 pounds contain the following ingredients, in the following proportions:

lbs.lbs.
12 partscarbon, each weighing 12, 144
22“hydrogen,“1, 22
11“oxygen,“16, 176
342

And the formula for glucose means that 180 pounds contain:

lbs. lbs.
6partsof carbon, @ 12, 72
12 “hydrogen,“1, 12
6“oxygen,“16, 96
180

And the formula for water means that 18 pounds contain:

lbs. lbs.
2 partsof hydrogen, @ 1, 2
1part “ oxygen,“16, 16
18

In fermentation, it is glucose which is immediately transformed, although cane sugar ferments also; but, before doing so, it becomes changed or inverted into glucose, and one molecule takes up a molecule of water, and produces two of glucose, thus:

Cane Sugar. Water. Glucose.
C₁₂H₂₂O₁₁ + H₂O =2 C₆H₁₂O₆
342+ 18   = 2 × 180 = 360.

Or, in the production of alcohol, 100 lbs. of pure cane sugar are equal to 105.26 lbs. of pure grape sugar.

The general formula for alcohol is C₂H₆O, and for carbonic acid CO₂.

Alcohol by Weight and by Volume.—The quantity of alcohol contained in a given mixture of alcohol and water may be expressed as per cent. by weight, or per cent. by volume. The first method is usually used by chemists, and the second in commerce. If we have 100 lbs. of a mixture of alcohol and water of which 10 lbs. are alcohol and 90 lbs. water, it contains 10 per cent. of alcohol by weight. If, however, we have 100 gallons of a mixture in which there are 10 gallons of alcohol and 90 gallons of water, we say that it contains 10 per cent. by volume of alcohol. This will serve to illustrate the meaning of the terms per cent. by volume and by weight, although it is well known that, owing to shrinkage, 10 gallons of alcohol and 90 gallons of water do not produce quite 100 gallons of mixture.

Whenever merchants and wine makers use the term per cent. of alcohol, they mean per cent. by volume or measure; and whenever the expression is used in this work, it is used in that sense, unless otherwise expressed.

Fermentation—Its Products.—Per cent. Sugar to per cent. Alcohol.—In theory, glucose, during the process of fermentation, is entirely changed into alcohol and carbonic acid; the two substances produced containing the same elements as glucose, and no others. If there was no loss of sugar, or degeneration, as it is called, the reaction would be exactly expressed as follows:

Glucose. Alcohol. Carbonic
Acid.
C₆H₁O₆=2 C₂H₆O+2 CO₂
180=92+88

And the old authorities said, if 180 parts of glucose produce 92 of alcohol, 100 will produce 51.1111, thus:

180 : 92 :: 100 : x = 51.1111,

leaving the balance to be accounted for by carbonic acid48.8889
100

And again, if it takes 100 parts of glucose to produce 51.1111 alcohol, how much does it take to produce 1 per cent. by weight?

51.1111 : 1 :: 100 : x = 1.9565.

These figures are now true only of that part of the sugar which is transformed into alcohol and carbon dioxide.

Different Authors.—Pasteur has shown that a portion of the glucose was changed into succinic acid and glycerine, and as the result of one of the experiments which he gives, out of a large number, it appears that 100 parts of glucose produce about 48.46 of alcohol, and it would require 2.063 to produce 1 per cent. of alcohol by weight, and 1.65 to produce 1 per cent. by volume.

But this eminent chemist’s experiments were conducted in the laboratory, and under the most favorable circumstances, so that no loss by evaporation could occur—conditions under which fermentation on a large scale is never carried on.

Dr. Guyot states that it takes about 1.5 per cent. of grape sugar to produce 1 per cent. of alcohol, which is even less than is required according to Pasteur, and is manifestly too little. And the statement has been made, that a must containing 20 per cent. of sugar will produce 13 per cent. of alcohol, which is impossible.

J. J. Griffin quotes Pasteur, and estimating the average loss to be 4½ per cent. of the sugar, deduces the figures .4881 as the per cent. by weight of alcohol produced by 1 per cent. of grape sugar. Dubief says that it takes 1.7 per cent. of cane sugar to produce 1 per cent. of alcohol by volume. Mr. Joseph Boussingault gives his experiments on musts fermented in small vessels under conditions similar to those under which fermentation is carried on in wine making on a large scale; and the result of his researches is that the product in alcohol is about 90 per cent. of what the chemical theory calls for: say, .46 by weight for 1 of sugar, or 1.7 + glucose for 1 per cent. of alcohol by volume. Mr. M. Boussingault gives it as the result of his experiment, that it takes 1.8 per cent. of sugar to produce 1 per cent. of alcohol.

So that it is pretty safe to say that it takes on an average about 1.8 of sugar to make 1 of alcohol, making some allowance for loss by evaporation, etc.

As has already been stated in the chapter on Musts, 1 per cent. for every 12 should be deducted from the percentage of sugar shown by the hydrometer for other matters than sugar.

If, therefore, we have a must which shows 24° by the saccharometer, we will deduct two, and call the remainder 22, sugar. Although it is not strictly correct to say that 22 divided by 1.8 will give the per cent. of alcohol which may be expected after fermentation, owing to the well known variation between per cent. by weight and by volume, as the figures increase, yet it is sufficient for all practical purposes.

Let us then divide 22, the supposed sugar in the must, by 1.8, the amount required to produce 1 per cent. of alcohol, and we obtain 12 and a fraction. Now the total indication by the saccharometer was 24 per cent.; if we divide this by two we get the same result in round numbers.

Hence the rule: one-half of the figure indicating the total per cent. by the saccharometer (hydrometer) is approximately the per cent. of alcohol to be expected in the wine.

Owing to the fact that the loss by evaporation and degeneration may vary greatly in different cases, this will be only a rough estimate, but it will prove as satisfactory as any method that can be adopted, and it corresponds very closely with the statement made by N. Basset, that in actual practice, a must of 20 per cent. gives only 7.88 per cent. of alcohol by weight, which corresponds with 10 per cent. by volume, nearly; and it is the rule given by Petiot and Dr. Gall for a natural must.

It seems, however, from what follows below, that this is only true of a normal must, but that a different rule applies to one of a very high degree of sugar.

Limits of Sugar and Spirit.—It is said that when a solution or a must contains over 35 per cent. of sugar, it will not ferment; nor will a wine or other alcoholic mixture which contains 20 per cent. of spirit ferment. Boireau says that the maximum of alcohol which a wine can attain by the fermentation of the richest must is between 15 and 16 per cent., and those wines which show a higher degree have been fortified. He says that the highest degree of spirit ever observed by him in a natural red wine was 15.4 per cent., when it was a year old; from that time the strength diminished, but the wine always remained sweet.

There is, however, a remarkable case given, and which seems to be well authenticated, of an Australian wine which contained naturally, by fermentation, 32.4° of British proof spirit, which is equal to about 18.21 per cent. And Vizitelli states that Mr. Ellis, of the firm of Graham & Co., asserts that perfectly fermented Alto Douro wine will develop 32° proof spirit, or 18 per cent. of alcohol, and when made exclusively from the Bastardo grape, as much as 34°, or about 19 per cent. of spirit. And Mr. Vizitelli adds that he is satisfied from what he saw at Jerez, that sherry wines which have had merely 1 or 2 per cent. of spirit added to them will in the course of time indicate 34°. To produce these results would seem to require more than 35 per cent. of sugar, according to our rule; but while it is approximately correct to say that 2 per cent. of sugar produces 1 per cent. of alcohol as long as we are dealing with a must of 24 or 25 per cent. and under, it may not be true of a must of 30 to 35 per cent., for the other solid matters probably do not increase in proportion to the sugar. Therefore, to reconcile this high degree of alcohol with the statement that a must containing over 35 per cent. of sugar will not ferment, we must use Pasteur’s figures, and then we will find that by them 35 per cent. of sugar is capable of producing over 20 per cent. of alcohol.

Temperature.—The temperature most favorable to fermentation—that is, at which it commences most promptly, and goes on the most rapidly—is between 77° and 95° F., and it does not cease until the temperature descends below 49°, or rises above 140°. If the temperature is favorable, fermentation ought to commence in ten or twelve hours from the time the pomace is put into the vat, or the juice into the barrel. In countries where the weather is cold at the wine making season, it is necessary that the grapes should be gathered in the heat of the day, or fermentation will be long in commencing; and if the weather continues unfavorable, so that the grapes do not become warmed by the sun, it is even necessary to heat a portion of the must artificially, and pour it into the vats or casks, or to raise the temperature of the fermenting house.

Mr. Maumené also recommends that the vats be surrounded with mats of loose straw, four or five inches thick, to be kept in place by a covering of linen cloth; and in this way the temperature produced by the fermentation may be maintained in cool weather, without resorting to fires in the fermenting house.

It is not necessary, however, that the temperature of the surrounding atmosphere should be as high as that indicated as most favorable to fermentation; for it commences readily in a temperature of about 70°, and the liquid will soon rise to 85° or 95°, by the heat developed during the process; and unless the surrounding temperature descends below 65°, this heat will be maintained, and the fermentation will not be checked. Dr. Guyot says, however, that, to make fine wines, it should be maintained at 68°, at least; and that, in other cases, it should not be allowed to fall below 60°.

Fermenting Houses.—It is important not only that fermentation should commence promptly, but that it should be maintained regularly; and although a great amount of heat is developed by fermentation, yet the must is liable to cool during the night and cold days, unless the vats and casks are protected from the change of temperature, whereby the fermentation may be checked, to the injury of the wine. The natural conclusion is that the must ought to be fermented in closed places. In California, however, it is not necessary to construct the fermenting house with the same care required in colder climates, where it is deemed desirable to furnish them with double windows and doors. It cannot be denied that good wine is made in this State, in places where the vats remain out of doors, shaded only by trees; but the practice is not to be encouraged, for the fermentation will be checked if the temperature of the surrounding atmosphere goes to 60° and below. In constructing a fermenting house, it ought to be so arranged, when practicable, as to be on a lower level than that of the stemmer and crusher, and higher than the cellar; for then the pomace and must can be run immediately into the vats and casks, and, after the first fermentation, the wine can be drawn off through a hose into the casks in the cellar, thereby saving time and labor.

CHAPTER VI.
RED WINE.

Red wines are made from colored grapes, and the color is extracted from the skins during fermentation. The coloring matter is blue, but is changed to red by the action of the acids in the must. (See [Coloring Matter]—[Oenocyanine].) In order to develop this color, the grapes are fermented, skins and juice together, and the press is only brought into requisition after the first fermentation is completed.

Fermenting Tanks or Vats.—The tanks or vats in which red wine is fermented, in France are generally made of oak, sometimes of masonry, but in this State redwood has been almost universally adopted, and I am not aware of any serious inconveniences from its use. It is advisable before using them the first time, to steam them for several hours, or thoroughly soak them to extract the coloring matter of the wood.

The capacity depends upon the quantity of wine to be made in a season, varying from 1000 gallons to 2500 gallons and more, and a sufficient number should be provided that when wine making has commenced, it can be carried on without interruption till the crop is worked up. The number of workmen must be considered as well as the amount of grapes, and everything ought to be so arranged that the fermentation will be finished in the first tank filled, by the time the last one is full, so that the first can be emptied and filled again, and then the second, and so on. A hole must be bored in each vat two or three inches from the bottom by which to draw the wine through a faucet. And some kind of a strainer must be put over this hole inside to keep back the marc—a piece of perforated tin, a grating of small sticks, or a bundle of straw or vine cuttings kept in place by a stone.

Filling the Tanks.—In order that the whole mass in one tank may be equally fermented, it should receive its full complement of grapes in one day. By putting in part of the grapes one day and part another, not only will some of them complete their fermentation before the others, but the addition of fresh grapes to the fermenting mass will interrupt the fermentation, and prove injurious to the wine. The vats must not be filled to their full capacity, for during violent fermentation the marc, consisting of skins and seeds, or those with the stems, rises to the top, brought up by the bubbles of carbonic acid which are constantly rising, and a portion of the boiling and foaming mass may be carried over the top, and much wine thereby be lost. They should only be filled to within a foot or a foot and a half of the top, and a little experience will show the proper practice. Guyot says that they should only be filled to five-sixths of their capacity at most. Another reason for not filling the tank is that a layer of carbonic acid gas will occupy the space left vacant by the pomace, and prevent the contact of the air and the consequent souring of the wine, by the changing of a portion of the alcohol into acetic acid—vinegar.

Red wine is fermented in open vats, vats loosely covered, or in vats hermetically sealed, and good wine is made in each way.

In Open Vats, other conditions being equally favorable, fermentation commences more promptly and is sooner ended, owing to the free access of the air, a certain amount of oxygen, as already shown, being necessary to fermentation. Although fermentation will continue away from the air when once started, it will be slow. The objections to open vats are, that although there is a layer of carbonic acid resting above the must, yet it is liable to be disturbed and become mixed with the air, and if the fermentation is long continued, a portion of the wine may become sour. Those who employ open tanks should also avail themselves of those conditions under which the wine will complete its fermentation in a few days, and should draw off promptly.

Closed Vats.—By using closed vats fermentation will be longer in commencing, and will proceed more slowly, but as already intimated, the wine can with safety be left longer in them than in open tanks. When it is necessary to develop much color, it would be advisable to use covered tanks, for the longer the wine is left in contact with the skins, the darker it becomes. The covering should be close enough to prevent the immediate contact of the open air, and yet allow the escape of gas—of close boards, but not luted, unless provided with a safety valve.

Fig. 5.

The Best Practice, however, in all cases, whether the vats are closed or not, is to have a false head resting directly upon the pomace, and which will keep the latter submerged during the whole process of fermentation. In this way good color will be developed, and the marc will be kept from the air, and the danger of souring will be avoided. In [figure 5], A represents a fermenting vat with the front half removed, showing the false head in place.

This head is made of several pieces which can be laid one by one upon the pomace, and maybe perforated with auger holes as represented in C, or may be a wooden grating, D. These pieces or sections together constitute the head B, and are kept in place by two cross pieces, e e, which are held down by blocks bolted or pinned to the inside of the tank. G is a stave with a block, f, attached, and H the same, showing the cross piece, e, slipped under it. When the tank is filled to the required height, the false head is put in, resting on the pomace, the ends of the cross pieces are slipped under the blocks, and everything is ready. As soon as the fermentation becomes violent, the whole will be submerged in the bubbling wine.

Hermetically Sealed Tanks.—Closely covered tanks must be provided with a safety valve or pipe for the discharge of carbonic acid gas, leading and discharging into a vessel of water, which completely prevents contact with the air. Under pressure the fermentation is much slower, and is not so complete. Yet great advantages are claimed for this method by some writers who maintain that by keeping the cover cool with wet straw or cloth, or by using a safety tube in the form of a worm passing through a condenser on the top of the vat, the vapors are condensed and fall back into the liquid, preventing loss of alcohol, and increasing the aroma, and that the wine acquires a superior fineness and velvety smoothness under the pressure of the gas. Boireau says that this latter quality is caused by the complete dissolution of the mucilaginous matters; and Pasteur has shown that more glycerine is produced when the fermentation is slow, which may contribute to the mellowness and smoothness.

Practice in the Médoc.—Mr. Boireau says that the greater part of the grand red wines of the Médoc, the prime St. Emilion, and the prime Graves, are fermented in closed vats; though a certain number of the viniculturists still follow the old custom, and make their wine in open vats.

Stirring the Pomace in the Vats.—In Burgundy, and in some other parts of France, it is considered necessary to give the mass a thorough stirring (foulage) during the active fermentation, in order that all parts may be equally exposed to the action of the ferment, and also that a good color may be developed; and for this purpose men enter into the vats and thoroughly mix the pomace and stir it about with their naked bodies and limbs, a practice not only disgusting in the extreme, but dangerous for the men, who are exposed to the poisonous effects of carbonic acid. It is by no means a general practice, and is of doubtful utility, even if it should be done by other agents than the naked human body.

It is evident that two opposing forces are at work when the must is stirred during fermentation. By the aeration fermentation would naturally be increased; but Dr. Guyot shows that stirring actually diminishes its activity, and he advocates the practice in order that the fermentation be not too tumultuous. The temperature of the surrounding atmosphere being lower than that of the fermenting mass, aeration by stirring must, by lowering the temperature, diminish the activity of the fermentation. Mr. Haraszthy, in his lecture before the Convention of Viniculturists in 1882, recommended that the mass be stirred when the fermentation commences to lag, on the theory that by thus mixing again the yeast with the liquid, so exposing it again completely to the action of the ferment, fermentation would start again with renewed vigor. It can easily be stirred with poles provided with shoulders or short cross pieces.

It has already been stated that the must is sufficiently aerated by crushing the grapes with rollers, and where the vats are provided with a false head to keep the pomace submerged, the wine will have sufficient color without the stirring; and it would seem that the wine would clear sooner if the lees were not stirred into it near the end of fermentation. Where the vats are not covered, and the grapes are not stemmed and not kept submerged, a crust or cap is formed on the top of the fermenting mass, which sours and rots if long exposed to the air, and the mixing of this with the liquid has a most deleterious effect upon the wine.

When to Draw from the Vats.—When the first or active fermentation in the vats is completed, the new wine must be drawn off into pipes, and thus be separated from the marc, consisting of skins, seeds, and sometimes stems, and also from the heavy lees which has settled in the vats, and it is important to know the proper time to do this.

The duration of active fermentation depends upon several causes and conditions as already indicated, such as heat, the amount of sugar contained in the must, whether the vats are covered or open, the immersion of the marc, and whether the grapes are stemmed, etc. It may be completed in four or five days, or it may continue for fifteen or twenty days. In case of musts poor in sugar it may rarely terminate in twenty-four hours. In some parts of France the grapes are allowed to macerate for weeks and even months (for they cannot ferment actively for that length of time), and what might be good wine, thus is often spoiled.

The Objections to Long Vatting are that the marc will absorb an undue amount of alcohol, as is shown when it is submitted to distillation in brandy making, for marcs which have remained long in the vats with the wine yield more spirits, and, of course, the wine is deprived of so much strength. This objection, however, would have but little force where the grapes are stemmed. Another and more serious objection is, that by a long exposure to the air which is apt to take place when the vats are not closely covered, some of the alcohol will be changed to vinegar, and the wine will rapidly degenerate, and become sour. Long contact with the seeds, skins and stems also produces a foreign taste in the wine known to the French as goût de râpe, stem flavor; and it is obvious that if the marc is allowed to remain in the liquid till it macerates and rots, it will acquire a still more disagreeable aroma and flavor. It is also said that some varieties of grapes which will not produce a wine with a bouquet, when allowed to remain long in the tank, will develop it in a vatting of short duration. The only advantage to be gained by leaving a wine in the vat after the active fermentation is finished, is in the way of color. When it is desirable—if it ever is—to produce a dark-colored wine at the expense of other good qualities, it may be left in the vat to soak. Such wines have their use, and that is to mix with those which lack color, but it is much better to mix in a quantity of grapes which naturally produce good color.

In making Fine Wines, a dark color is not looked for nor desired, but rather a bright and lively red; and they should be allowed to remain in the vat only long enough to convert the greater part of the sugar into alcohol.

How to Know when to Draw from the Vat.—It is said in general terms that the wine should be drawn from the vat when the active fermentation is finished. This is known by the taste of the wine by those long familiar with the vinous flavor which takes the place of the sweet taste of the sugar; it is also recognized by the cessation of the production of carbonic acid and the consequent bubbling, the falling of the temperature, the settling down of the marc, and by the clearing of the liquid. If the must or new wine shows from 0° to 1° by Baumé’s hydrometer, or from 0° to 2° by Balling’s saccharometer, nearly all the sugar will have been converted into alcohol; I say nearly all, for all the sugar is not converted till long after the wine is drawn from the vat. Boireau says that the fermentation is yet incomplete when the hydrometer marks several degrees of density, and the liquid is warm, sweetish, and muddy. He says, moreover, that care should be taken that active fermentation has entirely ceased before putting the wine in pipes, for if it is still sweetish and fermenting, it will remain sweet a long time, and ferments will often remain in suspension, which will render the wine difficult to clear, and liable to ferment and become sour.

Method of Drawing from Vats and filling Casks.—If the pipes are on the same level with the vat, or higher, the new wine is run from the vat through a faucet into buckets and carried in them to the casks and poured into these through a funnel, or is run into a large receptacle or tub placed immediately under the faucet and pumped into the casks by means of a force pump. But the more expeditious way is to have the casks ranged on a level lower than the bottom of the fermenting tank, and then to run the wine directly into them through a hose attached to the faucet. Of course, careful men must be in attendance to watch the operation, and close the faucet as soon as the cask is filled, and immediately transfer the hose to an empty one, so that the wine may not run over and waste.

Where the wine is drawn from more than one vat, it should be equally distributed through all the casks, so that the quality may be as nearly uniform as possible. If the press wine is to be mixed with the vat wine, the casks should only be filled to three-fourths or four-fifths of their capacity, in order to leave room for the former.

Fig. 6.

Wine Presses.

Wine Presses.—Wine presses are constructed in several different forms, and the force is applied by means of a simple lever, consisting of a long timber weighted at the end and rigged with a rope and pulley to raise and lower it, or by means of a large screw. Hydraulic presses are also used in large establishments. It is not necessary here to give a detailed description of a press of either kind, for the prospective wine maker will examine the different ones and see them in action, and choose according to his means and necessities. [Fig. 6] represents screw presses. A very simple one, however, and which can be made by any carpenter, consists of a box two or three feet square, and a foot or more high. This box, however, is made up of sections, each of which is five or six inches high; and they should be constructed of strong two-inch timber, well mortised together, and perforated with small holes through which the wine may ooze out. The height, and consequently the capacity of the box or receptacle will depend upon the number of sections used. A broad board constitutes the bottom of the press and should be larger than the receptacle itself, and be provided with a rim open in the middle of the lower side, and having a shallow spout for the wine to run through. This bottom is firmly placed so as to incline slightly forward, the sections are placed on it, one on the other, till the box is of the desired height, then the marc from the vat is filled in and a head or follower fitted to the inside of the box is placed on the marc, and pressure is applied with a lever. This lever is a strong piece of timber with its fulcrum end placed in a mortise in a large tree, or adjusted in any other suitable manner, allowing free play to the other end to which is attached the rope and pulley to facilitate its movement.

Pressing and Press Wine.—In the manufacture of all but fine wines, it is the usual practice to mix the press wine with the wine from the vat. And as the wine remaining in the pomace is about one-fourth of the whole, it will be equally distributed among all the casks by filling with it the vacancy left in them. If a light pressure is first applied, the wine of the first pressing will differ but little from the vat wine. After this, however, the marc should be spaded and stirred and pressure applied again, and the process repeated till the wine no longer flows. During the last pressing it is necessary to apply so much force that a great amount of coloring matter is pressed from the skins, and tannin from the seeds, and also from the stems when not removed, and the advantage of color may be more than counterbalanced by the excess of tannin. There may be danger of giving the wine too much astringency by mixing the last pressings.

Special Practice for Fine Wines.—Mr. Boireau indicates the practice in making common wines, as follows, as a warning to those who can make fine wines. He says that the wine which the marc contains is removed by pressing it almost to dryness, and that the wine thus obtained is very muddy, very harsh, and sometimes sour, particularly when the upper part of the crust has not been removed, where open vats are used and the marc not submerged. The greater part of the proprietors of the ordinary growths have the deplorable habit of mixing the press wine, without clearing it, with the limpid part drawn from the vat. He says that it should be kept separate, or otherwise the better part of the wine will be made muddy and difficult to clear.