be isolated in pure cultures were beer and
wine yeasts prepared in the laboratory of
the Carlsberg Brewery in Copenhagen
around 1880. And scientists coined the
wor d enzyme, denoting the remarkable
protein molecules that living cells use to
transform other molecules, from the Greek
words for “in yeast,” where sugar is
transformed into alcohol.
Physical and Chemical Qualities Pure
alcohol is a clear, colorless liquid. The
alcohol molecule is a small one, CH 3 CH 2 OH,
whose backbone is just two carbon atoms. One
end of the alcohol molecule, the CH 3 ,
resembles fats and oils, while the OH group at
the other end is two-thirds of a water
molecule. Alcohol is therefore a versatile
liquid. It mixes easily with water, but also
with fatty substances, including cell
membranes, which it excels at penetrating,
and aroma molecules and carotenoid
pigments, which it excels at extracting from