The darker varieties of beer are sometimes artificially coloured by the addition of caramel, and, although the result reached is virtually the same as that caused by the over-roasting of malt, the practice is prohibited in Germany unless the product is designated as “coloured beer.”[85] According to Guyot, some of the Bavarian beer sold in Paris is coloured with methyl orange.[86] Licorice is employed in beer brewing in Germany, both on account of its sweetening power and for clarifying purposes.

In regard to the use of artificial preservatives, such as salicylic acid and sodium bisulphite, it is very probable that articles of food which have been treated with these preparations are not readily digested. Their use, moreover, should be unnecessary, if due care has been exercised in the manufacture of the beer. This is especially applicable to beer intended for home consumption.

WINE.

Wine is the fermented juice of the grape of Vitis vinifera. In its preparation, the fully matured grapes are usually (but not always) first separated from the stalks, and then crushed, the marc so obtained being afterwards placed in butts provided with perforated sides, through which the expressed juice or must percolates. It is next introduced into vats, and allowed to undergo a process of fermentation, which is very analogous to that of beer wort. The addition of yeast is, however, in this case unnecessary, as the fermentation of grape-juice is spontaneous, it being due to the generation of the fungus Penicillium glaucum, which is the product of the action of atmospheric germs upon the albuminoid matters contained in the must. The most important constituents of grape-juice are glucose (10 to 30 per cent.), organic acids (0·3 to 1·5 per cent.), and albuminous substances. During the fermentation the glucose is converted into alcohol and carbonic acid, the latter being evolved in bubbles; a deposit of potassium bitartrate and yeast-cells, forming the lees, likewise occurring. This first fermentation ceases after the lapse of several days, the period being indicated by the cessation of escaping gas. In order to prevent the oxidation of the alcohol to acetic acid, the liquid is removed from the lees and transferred into casks, in which a slow after-fermentation and a further separation of potassium bitartrate take place. The wine is subsequently stored for a considerable time in fresh casks, during which it “ages,” and acquires its characteristic flavour.

The more common varieties of wine are classified according to the country of their production—into French (claret, burgundy, champagne, etc.), German (Rhine), Spanish (sherry and port), and Italian.

The production of American wine has experienced a noteworthy increase during the past twenty-five years. While, in 1860, less than two millions of gallons of native wine were consumed in the United States, in the year 1884 the quantity used exceeded seventeen millions of gallons.[87] Aside from the general distinction of red and white, wines are classified by their characteristic properties, as dry, sweet, and cordial. In dry wines, such as those of the Gironde and Rhenish districts, considerable free acid, and but little or no sugar are contained, whereas in sweet wines (Madeira, port, etc.) a certain proportion of the sugar remains undecomposed. Cordial wines are distinguished by their sweetness and comparatively heavy body. The nature of wines is materially affected by the proportion of glucose and acids contained in the original must, as well as by the environments of their manufacture, such as climate and temperature. From a chemical point of view, the most important constituents of wine are the primary products of fermentation—alcohol, succinic acid, and glycerine, but its market value is far more dependent upon the flavour and bouquet, which are chiefly due to the formation of secondary products, usually included under the name “oenanthic ether,” and consisting of the ethers of caproic, caprylic, and other organic acids.

The following table exhibits the constituents of some of the best known varieties of wine, according to results obtained by different authorities:—

Kind of Wine.Specific Gravity.Alcohol,
by Weight.		Fixed
Acids (as
Tartaric).		Volatile
Acids (as
Acetic).		Total Acids.Real Tartaric Acid.Total Residue.Sugar.Ash.Potassa (KOH).Potassium Carbonate.Sulphates
and
Chlorides.		Phosphoric Acid.
per
cent.		per
cent.		per
cent.		per
cent.		per
cent.		per
cent.		per
cent.		per
cent.		per
cent.		per
cent.		per
cent.		per
cent.
French
(red)[88]		0·995012·000·4200·1700·5900·1802·430·2000·220..0·0600·100·03
French
(white)		0·992210·840·4350·1690·6040·1021·2570·8800·197......0·031
Vin Ordinaire..6·990·6100·1100·720..5·040·1100·4500·13......
St. Julien (1858)..9·840·5100·1400·650..2·670·2500·400......0·080
Frousac..10·740·4500·2700·720..2·360·3700·270......0·040
Champagne..7·95....0·520..12·4110·630·25......0·050
Rhenish[a][88]0·99349·260·4200·1100·5300·2501·8500·0120·170..0·070·070·03
Rüdesheimer..13·32....0·630..1·8400·0170·170..0·07....
Alsatian[a][88]..10·38..0·6100........0·178......0·0253
Würtemberg..7·090·87......2·22..0·2300·09......
Sherry[a][88]0·994017·200·2700·1500·4200·0184·202·560·450..0·0010·360·02
Port[a][88]1·004018·560·3100·0800·3900·0227·554·330·280..0·050·1300·03
Madeira[a][88]0·994017·750·3300·1600·4900·034·352·080·39..0·030·250·04
Marsala[a][88]0·996016·710·1900·1100·300..4·983·240·22..0·020·150·02
Red Vœslauer..10·250·4800·0600·540..1·960·290·320·14......
Lachryma Christi..9·700·4600·1100·560..23·6318·910·480·10......
White Capri..10·400·4600·1900·650..1·960·480·290·11......
Cyprus..10·090·4800·1200·600..23·8122·120·530·11......
Greek[a][88]0·993113·890·2330·1770·7100·032·550·360·37..0·020·240·04
Hungarian[a][88]0·99218·540·5300·1500·7000·0671·820·060·17..0·010·080·02