On Food and Cooking

relatively cool temperatures, between about
59 and 82ºF/15–28ºC. The desirable stable
crystals (sometimes referred to as “beta” or
“beta prime” or “Form V” crystals) melt only
at warmer temperatures, between 89 and
93ºF/32–34ºC. The temperature range in
which a particular kind of crystal melts is also
the range in which it forms as the chocolate
cools. Unstable crystals therefore form when
molten chocolate is cooled rapidly, so that the
stable crystal types — the ones that begin to
form at warmer temperatures — don’t have
time to gather most of the fat molecules to
themselves before the unstable crystals begin
to form. Stable crystals predominate in melted
chocolate when the cook carefully holds it at
temperatures above the melting point of the
unstable crystals, but below the melting point
of the stable crystals. This tempering range is
88–90ºF/31–32ºC for dark chocolate,
somewhat lower for milk and white
chocolates thanks to their mixture of cocoa