On Food and Cooking

tremendously, from unfermented to badly
overfermented and even moldy. The first
challenge for the chocolate manufacturer is to
find good-quality, fully fermented beans.
Soon after the cacao pods are harvested,
workers break them open and pile the beans
and sugary pulp together at the ambient
tropical temperature. Microbes immediately
begin growing on the sugars and other
nutrients in the pulp. A proper fermentation
lasts from two to eight days, and generally has
three phases. In the first, yeasts predominate,
converting sugars to alcohol and metabolizing
some of the pulp acids. As the yeasts use up
the oxygen trapped in the pile, they are
succeeded by lactic acid bacteria, many of
which are the same species found in
fermented dairy products and vegetables.
When workers turn the mass of beans and
pulp to aerate it, the lactic bacteria are
succeeded by acetic acid bacteria, the makers
of vinegar, which consume the yeasts’ alcohol