On Food and Cooking

that rapidly degenerates when heated, so
peppermint is usually not cooked. Its
concentration increases with the age of the
leaf, so older leaves taste more cooling; hot
and dry growing conditions cause menthol to
be transformed into a noncooling, somewhat
harsh by-product (pulegone, the characteristic
volatile in pennyroyal).
A handful of other mints are worth
knowing about. Watermint, one of the parents
of peppermint and sometimes called bergamot
or orange mint, has a strong aroma and used
to be much cultivated in Europe, but now is
more popular in Southeast Asia. Pennyroyal
(M. pulegium) is an especially pungent,
peppery minor mint, apple or pineapple mint
(M. suaveolens) a sweet, apple-like one, and
Mentha x piperata “citrata” the perfumy
lemon or eau de cologne mint. Nepitella is the
Italian name for Calamintha nepeta, a
sometimes minty, sometimes pungent herb
native to the southern Mediterranean, used in