is sulfites, sulfur compounds that can induce
an allergic reaction in sensitive people.
The second additive is either sugar or acid,
and it is used to correct the balance between
these two substances. Grapes that ripen in a
cool climate can lack the sugar to produce
enough alcohol for a stable wine; grapes that
ripen in a hot climate metabolize some of
their acids and can produce a flat-tasting
wine. French winemakers usually add sugar;
California winemakers often add tartaric acid.
The Alcoholic Fermentation
The Fermentation Yeasts Fermentation can
begin with or without the addition of a starter
culture of yeast. The winemaker can choose
among many different strains of
Saccharomyces, or allow the fermentation to
begin spontaneously with “wild” yeasts from
the grape skins (species of Kloeckera,
Candida, Pichia, Hansenula, and others).
These are always eventually displaced by