These observations lead to a removal of the difficulties that lay in the way, and, at the same time, suggest a mode of applying the present, or of constructing a future hydrometer, for ascertaining the strength or the quantity of the vinous spirit in beer, wine, ale, and other fermented fluids, which has long been a desirable object.
The distiller, having none of these niceties to attend to, is governed by the ultimate extent of the attenuation the worts, or wash, is found capable of, and which is both assisted and protracted by its superior density, in its progress from specific gravity to specific levity, if such an expression is admissible.
Fermentation, begun in a fluid more or less saturated with saccharine or fermentable matter, the process is finished sooner or later, and usually in proportion to the degree of saturation, and the being conducted with more or less vigour under a well regulated temperature; for the more a fluid abounds with this matter, the grosser and denser it must necessarily be, and the longer will the attenuation be protracted; the longer it is protracted, in air-tight vessels, and in a healthy and vigourous state of decomposition, the more spiritous and strong will that wash turn out, and the greater the produce of spirit in distillation; hence, it is both protracted and assisted by its density.
A languid may be truly called an unhealthy decomposition, it being productive of diseases common to misconducted fermentation, acidity, putridity, and lack of spirits, with a tendency to precipitate and burn upon the bottom of the still; hence, all the decompositions are confounded together, as in spontaneous fermentation.
The formation of acidity during the process, is not of that injury to the distiller that it is to the brewer, nor is this recent acidity vinegar, as has been supposed by some chemists, but the incipient state of combination of resolving elements, whose particles are in that juxtaposition best suited to absorb developing hydrogen in a nascent state, and intimately to combine with it into vinous spirit, the approximation to which is promoted by time and incumbent pressure: these positions shall be explained as I proceed.
The reason that putridity is so rarely discovered in excited fermentation, is, that it is usually counteracted by the previously evolved acidity, and corrected, but not saturated or neutralized; for, were that the case, the putrid could not immediately succeed the acetous process in the same fluid, nor exist together, as they are known to do in declining beer, vinegar, &c.
The reason that acidity is not more frequently observed and attended to than it is, is because of its being sheathed or covered by the unattenuated sweets, or fermentable matter of the wash that remains undecomposed.
On the other hand, when acidity is very prevalent, it may be mistaken for unattenuated fermentable matter, acidity increasing the density and specific gravity of the fluid.
Putridity, from the avolation of its products, promotes levity, and that in proportion as its increase surpasses that of the general acid; and it is not until the action of the acetous becomes languid, that the putrid process gains the ascendency, when it is then difficult to overcome.
Although these observations may show how the hydrometer, or its use, in unexperienced hands may be baffled, they both distinguish and explain the value of its application; they do more—they elucidate the doctrine of fermentation, and illustrate the goodness of Providence, who has made nothing in vain, but provided nature with its own resources for conducting every operation in the great plan of the universe with uniform and unerring security.