cracks the inner shell open. Traditionally, the
ripe fruits were knocked from the trees and
sun-dried, and the hull pigments stained the
shell, so the shells were often dyed to make
them a uniform red. Today, most California
pistachios are hulled before drying, so the
shells are their natural pale tan color.
Pistachios are remarkable among the nuts
for having green cotyledons. The color comes
from chlorophyll, which remains vivid when
the trees grow in a relatively cool climate, for
example at high elevation, and when the nuts
are harvested early, several weeks before full
maturity. Pistachios thus offer not only flavor
and texture but a contrasting color in pâtés,
sausages, and other meat dishes, and in ice
creams and sweets. The color is best retained
by roasting or otherwise cooking the kernels
at low temperatures that minimize chlorophyll
damage.
Walnuts Walnuts come from trees in the