On Food and Cooking

Kefir 0.1%  alcohol

Sour cream, crème fraîche, and buttermilk
are indigenous to relatively cool western and
northern Europe, where milk spoils more
slowly and was often left overnight to
separate into cream for buttermaking. The
lactococci and Leuconostoc species that
produce them are “mesophilic,” or moderate-
temperature lovers that probably first got into
milk from particles of pasturage on the cows’
udders. They prefer temperatures around
85ºF/30ºC but will work well below that
range, and develop moderate levels of lactic
acid during a slow fermentation lasting 12 to
24 hours.

Yogurt

Yogurt is the Turkish word for milk that has
been fermented into a tart, semisolid mass; it
comes from a root meaning “thick.”