On Food and Cooking

oozes from the freshly cut base. Though
lettuce is now mostly eaten raw in the West,
in Asia it’s often shredded and cooked. This
can be a good use for the older, tougher leaves
sometimes found on supermarket lettuces.
There are several broad groups of lettuce
varieties, each with a characteristic growth
form and texture (see box below). Most
lettuces have a similar taste, though some red-
leaf lettuces are noticeably astringent thanks
to their anthocyanin pigments. Generally,
varieties whose leaves are shielded from
sunlight by the formation of a head offer
much lower levels of vitamins and
antioxidants. The pale, watery crisphead
variety known as iceberg triumphed in the
United States due to a combination of its
durability in shipping and storage — it
brought lettuce to the American table year-
round in the 1920s — and its refreshing,
crunchy-wet texture. Head lettuces respire
more slowly and so keep better than leaf