As we have seen, red wine is fermented "on the skins" in order to
extract the coloring matter and other ingredients lodged in the skins.
In making white wine, the grapes are crushed and the fresh juice
immediately separated by pressing so that it may ferment apart from the
skins.
This fresh juice is checked for its sugar content and acidity, as in
preparing to ferment red wine, and the proper corrections are made
immediately after pressing. Likewise, a yeast "starter" is added.
The fermentation takes place in the same 5-gallon glass containers that
are later used for storage. But as fermenters they are filled only
two-thirds full as a precaution against any overflow or unmanageable
formation of bubbles.
When the primary fermentation has run its course, the several
partly-filled bottles are simply consolidated--filled full and equipped
with bubblers. Subsequent siphoning from sediment, chilling, and dosing
with meta are carried out as with red wine.
If fining is necessary, it differs in one respect: before mixing in the
gelatin, mix in an equal amount of dissolved tannic acid to remove the
impurities. Tannic acid is obtainable at drug stores or winemakers'
shops as a powder. This provides better settling out of suspended
matter.
Dry table wine is a food beverage, to be used with meals. Sweet wines
are more like cordials.
The making of sweet wines takes advantage of a characteristic of the
yeast organism, namely, that its activity dies down and it usually
ceases to ferment sugar into alcohol after a fermenting liquid reaches
an alcoholic content of around 13%. The secret, then, is to add an
excess of sugar when correcting the juice of crushed grapes before
fermentation. When fermentation ceases, there is still some residual
sugar in the juice. From then on the still-sweet new wine is treated
much as other wine.
The three important differences are: (1) the wine is siphoned from its
sediment immediately after fermentation, without the waiting period at
60° F; (2) the chilling begins as soon as possible; and (3) the dose of
meta added then and at each subsequent siphoning is doubled (½ teaspoon
per 5 gallons instead of ¼ teaspoon) to guard against spoilage and
against any accidental resumption of fermentation.
Dry table wines made from other fruits are rarely successful, but
agreeable sweet wines may be made from them. The point to remember is
that most fruits are lower in sugar than grapes and higher in acid.
Corrections for both are almost always necessary, plus sufficient excess
sugar to leave residual sweetness after fermentation.
These fruits, with the exception of apple juice, are fermented in a
crushed mass in order to obtain a maximum extraction of characteristic
odors and flavors. Once fermentation is concluded, they are treated like
sweet grape wine. The table will serve as a rough guide to their
relative sugar content and total acidity.