666 WINE the higher latitudes, and with the juices of other fruita than the grape, it has been more common to add to the must a quantity of sugar, especially of late years starch sugar ; this may serve to consume all the ferment, generating of course more alcohol, and perhaps still leav- ing an excess of sugar ; so that a wine thus treated is always stronger than otherwise, and may also he sweet. If, after the sugar is ex- hausted, there ia still a portion of ferment re- maining in the wine, or if fermentation is purposely arrested while such is the case, then this ferment is liahle, and often for a long time, to set up the acetous fermentation, or change of the alcohol to vinegar, whenever the conditions favoring this change occur ; these conditions are access of air to the wine, and the rather high temperature required to cause the action of oxygen upon the alcohol. Wine which begins in this way to acetify is said to be " pricked." The addition of more sugar in such case, often resorted to with a view of arresting this change, is very apt to hasten the decomposition. The preferable plan is to remove the wine immediately to a very cool place, as a cellar, and to leave it at rest for some time with limited access of air. Mulder calculates that 198 parts by weight of grape sugar, no loss being supposed, will give 92 parts of alcohol, or nearly in the proportion of one part of the latter to two of the former. But besides the varying percentage of sugar in the must, the facts that a portion of it may continue unchanged, and that during fermen- tation more alcohol than water is likely to evaporate, render it impracticable to predict in given cases what proportion of alcohol the wines produced shall contain. The exciting and intoxicating qualities of wines result, of course, from the presence and amount of the alcohol developed in them. From such causes as the mixture of the perfect fruit with more or less that is unripe or decayed, the fluctua- tions of temperature that may attend the fer- menting process, &c., wines even from the same variety of vine, and in different years from the same vintage, may be exceedingly dissimilar; and as a rule the composition of wines, even if pure, is far less subject to pre- cise knowledge or determination beforehand than is that of the grape juice. While alcohol is forming, some of the components of the juice entirely or nearly disappear in the froth or sediment, and others are chemically changed, resulting in the production of new compounds. Since the juice of all grapes is colorless, it fol- lows that when the expressed juice, separated wholly from the pulp and skins, is fermented alone, the wine will be perfectly colorless, or that known as " white," no matter what may have been the color of the grapes used. White wines will necessarily at the same time almost or wholly lack tannic acid, which is present in the skins. But if the crushed grapes and juice be left to ferment for a time together, how- ever light the former, the liquid will acquire some color (at the least a tinge of amber) ; and the color will be deeper, to the very dark red of such wines as port, according as the skins of the grapes were of darker color, or as the time during which they remain in the ferment- ing juice is prolonged. Thus, natural color in wines is always that extracted from the skins of the grapes in the vat, and is not, as often supposed, due to the choice of purple grapes. But the presence of color will, for the like reason, always be attended with that of tannic acid, so that in some degree the colored wine will be rough or astringent ; and the degree of astringency duo to this cause will usually be proportional to the depth of color, a fact of which port wiue also affords a marked instance. Alumina is said to be detected chiefly in the red wines, and in some of them also a trace of iron. The other free acids are such as named in stating the composition of the juice, tartario being generally the most abundant ; in soured wines, including those that have become musty or hurt with age, acetic acid is also present. Wines bottled while the process of fermenta- tion is going on will also contain carbonic acid gas, and will in consequence, if drunk immedi- ately on uncorking, have the quality of " brisk- ness ;" where the quantity of the gas is consid- erable, such wines sparkle when agitated in the light, and they are then distinguished as "sparkling," while those which do not sparkle are distinguished as "still." Wines always contain less of tartario acid than the grape juice they are obtained from, owing to the cir- cumstance that during the generation of alco- hol the tartrates in the juice, and mainly the tartrate of potash, become insoluble and are thrown down ; the considerable masses of nearly pure tartrate of potash thus found in the bottom of the vat or cask are an important source of that salt in commerce, and pass un- der the name of wine stone, crude tartar, or argol ; the slight further deposition that may take place after bottling is known as "crust" or " beeswing." That quality in wines which in liquids generally would be known as flavor, must depend mainly in the former on the acids, sugar, and alcohol ; but the fragrance and an important part of the actual flavor of wines are due to the presence of some peculiar vola- tile matter, the effect of which is technically distinguished from the simple flavor, and which is known as the perfume or bouquet of the wine. The nature of this odoriferous principle is not satisfactorily known. According to Fau- re, it is a viscid substance diffused in the liquor, which he terms ocnanthine. According to Lie- big and to Winckler, it appears rather to be or to contain a peculiar ether, or a volatile fra- grant acid ; to the former the name of oenanthio ether has been given. Water is more abundant in wines made in wet seasons, and in the wine from new vineyards or young vines ; of course also in wine from any grape in which the pro- portion of sugar is very small. Weak wines ore more prone to become sour ; and it was to
