WINE. A term applied by chemists to all liquids that have boom vinous by fermentation ; but it is popularly considered as confined to sacchmaa vegetable substances that have been converted into a vinous liquid. It seam to be a neeenssry condition, that sugar must be present in a vegetable, to end& it to ferment and become vinous ; 'bat -ding to We discoveries, will not exclude snub, gum, and other similar products, which are capable of bang converted into saccharine matter. Lavoisier stated that pure sugar alone would not ferment, but that some extractive matter, or yeast, must be added to enable it to undergo the vinous fermentation ; and he considered that the effects of this fermentation consisted in separating the sugar, which is an oxide, into porn; in oxygenating the one, at the expensed the other, to form carbonic arid; in disoxygenating the other in favour of the first, to form a combustible substance termed alcohol; an that, were it possible to combine these two substance., the alcohol and the carbonic acid might reproduce sugar. It is neoawry to remark, that the hydrogen and carbomo do not exist in the state of oft in baron ol, being combined with a portion of oxygen, which renders them miscible with water. These three principles, therefore, the oxygen, the hydrogen, and the car bonic, are here in a kind of equaibrum ; and, in fact, by causing them to pass through a red-hot tube of glass or porcelain, we may recombine them, two and two together, and the product will be water, hydrogen, carbonic acid, and carbon.
In ell wines may be distinguished an acid, alcohol, tartar, an extractive matter, aroma or odour, and a colourless principle,—the whole being diluted or dissolved in a smaller or larger proportion ofwater. An acid exists in all wines, but all are not acid in the same degree. Of some wines a natural acidity is the prin cipal characteristic ; those produced from grapes not perfectly ripe, or that grow in moist climates, are of this kind ; whilst such u are theproduct of the fermenta tion of gram that have attained complete maturity and sweetness, contain but a very mall quantity of acid. The proportion of acid appears, therefore, to be in the inverse ratio of the saccharine principle, and consequently of the alcohol, which is produced by the decomposition of the sugar. Alcohol forms the true characteristic of wins. It is the product of the of sugar; and its quantity is always proportionate to that of the sugar that has been decomposed. Alcohol abounds more in some wines than it does in others ; those of hot climates contain a large quantity of it; whilst those of cold climates contain scarcely any. Ripe and sweet grapes produce it in abundance ; but the wines made of grapes that are unripe, watery, and sour, yield very little.
The following is Mr. Brande's valuable table of the quantity of alcohol in different kinds of wine and spirituous liquors Tartar exists in verjuice, as also in must; it contributes to facilitate the forma tion of alcohol. When left at rest in casks, it deposits itself upon the sides, forming a crust more or less thick, with crystals of irregular forms. Scene time before the vintage, when the casks are to be got ready for receiving the new wine, they are staved, and the tartar detached from them, in order to be em ployed in the different uses of commerce. This salt has little solubility in cold water, but considerably more in boiling water. It scarcely dissolves at all in the mouth, and it resists the pressure of the teeth. The extractive principle abounds in must, when it appears to be dissolved by the aid of the sugar; but when the saccharine principle is decomposed by means of fermentation, the quantity of extractive matter sensibly diminishes, a part of it deposits itself in a fibrous form, and this deposit, which principally constitutes the lees, is the more considerable in proportion as the fermentation is more gentle, and the alcohol more abundant. This deposit is always mixed with a consilernie quantity of tartar. There always exists in wine, a proportion of =user matter in a state of solution, which may be separated from it by means of eva poration. It abounds more in new wines than in old ones; the older obi wine grows, the more completely is it freed from the extractive principle Al natural wines have an odour more or less agreeable to the smell. Some of then owe their reputation in a great measure to the perfume which they exhale. This is the case with Burgundy. This perfume is lost by too violent a fermentation, and becomes stronger by age. It seldom exists in very spirituous wines, either because it is concealed by the strong smell of the alcohol, or because it has been destroyed or dissipated by the violent fermentation that was requisite to develop the spirit. The colouring principle of wine belongs to the skin of the grape ,
for when the mint is suffered to ferment without it, the wine is white. This colouring principle does not dissolve till the alcohol is developed; it is only ther that the wme acquires its colour, which is deeper in proportion to the violence of the fermentation. If we expose bottles filled with wine to the rays of the sun, a few day..are sufficient to precipitate the colouring principle in large pellicles ; the wine losing neither its perfume nor its strength. very great number of. vegetabli substances may be made to afford wine, as grapes, currants, mulberries, elders, cherries, apples, pulse, beans, peas, turnips, radishes, and even grass inelE Hence, ender the class of wines,_ or vinous liquors, come not only wines, absolutely so called, but also cyder, &c. The term wine is however in a more particular manner appropriated to the liquor drawn from the fruit of the vine. The process of making wine is as follows :—When the grapes are ripe, and the saccharine principle is developed, they are then pinned, and the jams which flows out is received in vessels of a proper capacity, in which the fermentation appears, and proceeds in the follow ing meaner. At the end of several days, and frequently after a few hours, and according to the heat of the atmosphere, the nature of the grapes,. the of the liquid, and temperature of the place in which the operation is pe a movement is produced in the liquor, which continually increases ; the volume of the !hid increases ; it become. turbid and oily ; carbonic acid I. disengaged, which Ma all the unoccupied part of the vessel; and the temperature rises to 73e Fahrenheit. The skins, stones, and other grosser matters of the grapes, are buoyed up by the particles of disengaged air that adhere to their surface, are variously agitated, and are raised m form of a scum, or soft and spongy crust, that covers the whole liquor. During the fermentation, this crust is fre quently raised, and broken by the air disengaged from the liquor, which forces its way through it ; afterwards the crust subsides, and becomes entire as before. These effects continue while the fermentation is brisk, and at last gradually cease: then the crust being no longer supported, falls in pieces to the bottom of the liquor. At this time, if we would have a strong Imd generous wine, all sensible fermentation must be stopped : this is done by putting the wine into close vessels, and carrying these into a cellar or other cool place. After this first operation, an interval of repose takes place, as is indicated by the cessation of the sensible effects of the spirituous fermentation ; and thus enables us to preserve a liquor, no lees agreeable in its taste, than useful for its reviving and nutritious qualities when drunk moderately. In this new wine a part of the liquor probably remains, that has not fermented, and which afterwards ferments, but so very slowly, that none of the sensible effects produced in the first fermen tation are here perceived. The fermentation, therefore, still continues in the wine, during a longer or shorter time, although in an imperceptible manner; and this is the second period of the spirituous fermentation,—which may be called the imperceptible fermentation. We may easily perceive that the effect of this imperceptible fermentation is the gradual increase of the quantity of alcohoL It has also another effect no less advantageous; namely, the separation of the acid salt called tartar from the wine. This matter is therefore a second sediment that is formed in the wine, and adheres to the sides of the containing vessels. As the taste of tartar is harsh and disagreeable, it is evident that the wine, which, by means of the insensible fermentation, has acquired more alcohol, and has disengaged itself of the greater part of its tartar, ought to be much better and more agreeable ; and for this reason chiefly, old wine is universally prefer able to new wine. But insensible fermentation can only ripen and meliorate the wine, if the sensible fermentation have regularly proceeded, and been stopped in due time. We know certainly, that if a sufficient time have not been allowed for the firstperiod of the fermentation, the unfermented matter that remains, being in too large a quantity, will then ferment in the bottles or close vessels in which the wine is put, and will occasion effects so much more sensible as the first fermentation shall have been sooner interrupted ; hence these wines are always turbid, emit bubbles, and sometimes break the bottles, from the large quantity of air disengaged during the fermentation.