On Food and Cooking

sweet potato to Europe, and by the end of the
15th century it was established in China and
the Philippines. China now produces and
consumes far more sweet potatoes than the
Americas, enough to make it the second most
important vegetable worldwide. There are
many different varieties, ranging from dry and
starchy varieties common in tropical regions,
some pale and others red or purple with
anthocyanins, to the moist, sweet version,
dark orange with beta-carotene, that is popular
in the United States and was confusingly
named a “yam” in 1930s marketing
campaigns (for true yams, see p. 306). The
bulk of the U.S. crop is grown in the Southeast
and cured for several days at 86ºF/30ºC to
heal damaged skin and encourage sugar
development. True to their subtropical
heritage, sweet potatoes store best at 55–60ºF/
13–16ºC. Chilling injury can contribute to
“hardcore,” a condition in which the root
center remains hard even when cooked.