Note 86 — Chapter II · AMERICAN GRAPES

Wine is the fermented juice of the grape. When the juice or must of the grape is exposed to temperatures ranging from 55° to 65°F. the micro-organisms which accompany the fruit, the yeast of the wine-maker, are transformed from a comparatively dormant state to one of great activity. The action of the organisms on grape must is called fermentation and through it certain physical and chemical changes take place whereby the must is changed in taste and in color, and a part or all of its sugar is changed into alcohol. The methods of making wine differ in different countries and in different localities depending upon the climate, kind of grapes grown, condition of growth, and the kind of wine produced, yet the principles and chief processes are much the same and may be briefly described as follows:

In general grapes are not picked for wine-making until they have reached full maturity thus insuring a higher sugar content, richness of flavor and perfect color. It is customary to determine the composition of the must as to sugar and acid content by various instruments devised for the purpose and if it lack sugar this ingredient is added; if it be too acid water is added; or the composition may be otherwise changed depending upon a number of circumstances though manifestly reputable wine-makers change the natural grape juice as little as possible. Soon after harvesting the grapes are crushed. The ancient method, which still prevails in many parts of Europe, was to tramp the grapes with bare feet or wooden shoes. Tramping is for most part superseded by mechanical crushers which break the skins but do not crush the seeds. For some wines the stems of the grapes are removed; for others it is essential that the grapes be not stemmed. Stemming may be done by hand, by a rake over a screen, or by specially devised machines. If white wine is to be made the juice is separated from skins and pulp at once; if red wine is desired fermentation takes place in the crushed grapes or marc.

Fermentation is carried on in large tanks or vats varying in capacity from 1000 gallons to 10,000 gallons or more. Some wine-makers prefer open vats, others keep them closed. The duration of fermentation depends upon many conditions and varies from two or three to fifteen or twenty days, depending upon the amount of sugar in the must, the temperature, activity of ferments, etc., etc. Wine-makers observe several distinct stages of fermentation which must be closely watched and controlled. A most important influence is exerted on fermentation by temperature. The limits below which and above which fermentation does not take place are 55° and 90°F. In general it is desirable that fermentation take place at temperatures ranging about 70°. When it is found that the sugar is practically all converted into alcohol, or that such conversion has proceeded far enough, the new wine is drawn or pumped from the fermenting vats into casks or barrels where it ages though it may require special treatment for clearing. Before bottling it is usually necessary to rack the wine into new barrels twice or three times to stop secondary fermentations which invariably take place.

Special treatments result in several distinct classes of wine. Thus we can divide wine into red and white as to color. Red wines are produced from colored grapes the color being extracted in the process of fermentation. White wines are made from light colored grapes or if from colored fruit the must is not allowed to ferment on the marc and so extract the color. We may again divide wines into dry and sweet. Dry wines are those in which the sugar is practically all converted into alcohol. Sweet wines are those which retain more or less sugar. These are often fortified by the addition of alcohol. A third division is that of still and sparkling wines. Still wines are those in which the carbonic acid gas formed by fermentation has wholly escaped. Sparkling wines retain a greater or less amount of this carbonic acid gas.

All of the above classes are further divided into well marked types according to their color and taste, their alcoholic content, and the countries in which they are produced. The following are the leading wines made from native grapes: Catawba, Delaware, Concord, Norton’s Virginia, Ives, Scuppernong, Iona, Claret, Port and Champagne. Of these Claret, Norton’s Virginia and Ives are red dry wines. Catawba, Delaware, Iona and Scuppernong may be either dry or sweet white wines. Port is a red sweet wine.