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tion is very variable, and the differences in the varieties of grapes 
~ used admit of almost endless modifications of the product obtained 
_ from them. Moreover, many other conditions affect more or less the 
composition of wine, as the nature of the soil, the climate, the method | 
- of cultivation pursued, the weather during the particular season when 
_ the grapes were ripened, etc. Thus the same variety of grapes, when 
- grown under different conditions of soil, climate, etc., produces dif- 
- ferent wines, and even in the same country the same variety of grape 
_ produces wines varying considerably in different seasons. 
The most important constituent in the grape is its sugar, from 
_ which the alcohol is formed, so as a general rule the grapes are al- 
- lowed to become fully ripened before they are removed from the vine. 
The first step is the production of the must. To this end the grapes 
Wine is properly the pure fermented juice of grapes; its composi-_ ui 
we 
_ are first bruised and crushed, either by the aid of machinery or by |. 
__ the more primitive but very effective method of trampling them by 
the feet of men. In some cases, and for very fine wine, the woody 
-stems are removed from the crushed grapes (dérdpage). In other 
- cases, especially in white wines, they are left, their contents of tannin 
+ making them a desirable addition to the grapes. To obtain the juice 
. the grapes are subjected to pressure. The amount obtained varies 
- with the means employed, the kind of grape, etc., but may be stated 
at about 60 to 70 per cent. of the weight of the grapes. For red wines . 
_ the juice is allowed to stand in contact with the skins a variable length 
of time until it has acquired from them the desired depth of color, 
and in this case the fermentation commences before the juice is ex- 
pressed. All musts contain pretty much the same proximate princi- 
. ples, their differences being due solely to the relative proportions of, 
the different constituents. Briefly stated, these constituents are as 
follows: ae 
(1) Saccharine matter (chiefly dextrose), which may constitute as 
high as 25 to 30 per cent. of the must. ; 
. 3 Albuminoid matter. 
*. (3) Gummy maiter, pectin, etc. 
4) Extractive matter, illy-defined substances, comprising the col- 
oring matters, if any, the flavoring matters, etc. 
©) Organic acids and their salts, comprising malic acid (especially 
in bad seasons), a slight trace of tannic acid derived either from the 
stems or skins, and tartrates of potassium and calcium. 
(6) Mineral matters: Phosphoric, sulphuric, hydrochloric, and 
_ silicic acids combined with potassium, sodium, iron, and magnesium. 
Water, 70 to 90 per cent.. 
The must is fermented in suitable vats of wood or stone, accord- 
ing to the usage of the country; the fermentation is produced spon- 
taneously, thatis, by germs accidentally introduced into it from the 
_ air or on the surface of the grapes themselves. If the fermentation 
~ does not take place promptly it is started up by introducing into it 
_ .asupply of yeast-cells from some must which is already in a state of, 
fermentation. Sometimes a small quantity of must is fermented in 
anticipation of the vintage season as a ‘‘ sponge,” its fermentation. ° 
being first induced by a small quantity of well-washed beer yeast. 
The use of albuminous yeasts, such as bread yeast, etc., is generally 
avoided as ‘much as possible, however, as tending to produce lactic 
and acetic or other objectionable fermentations entirely incompati- 
- ble with the production of a wine with a delicate flavor. 
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