On Food and Cooking

stripped away with the stem during
preparation — hence the name “string beans”
— were eliminated by a New York breeder in
the late 19th century; these days only
heirloom varieties tend to have strings. There
are two general forms of green bean, one with
round and thin pods, the other with flat and
broad pods. Flat varieties have been found to
have a more intense flavor. The flavor of
cooked green beans is interestingly complex;
it includes a number of sulfur and “green”
compounds, but also the essence of fresh
mushroom (octenol) and a flowery terpene
(linalool).
Good-quality green beans can be hard to
find, because they’re one of the most fragile
vegetables. Their tissue is very active, so they
quickly consume their sugars and lose
sweetness even in cold storage. And thanks to
their subtropical origins, they don’t keep well
at refrigerator temperatures; their cells
become damaged and lose chlorophyll. Once