proteins must span and knit together — by a
factor of 6! And each tablespoon of sugar
surrounds every protein molecule in the egg
with several thousand sucrose molecules.
Because the egg proteins are so outnumbered
by water and sugar molecules, the coagulation
temperature in a custard is between 10 and
20ºF higher than in the undiluted egg, between
175 and 185ºF/79–83ºC. And the protein
network that does form is tender, tenuous, and
fragile. Exceed the coagulation range by just 5
or 10ºF and the network begins to collapse,
forming water-filled tunnels in the custard,
grainy curds in the cream.
Gentle Heat Many cooks have known the
temptation to crank up the heat after a custard
has been in the oven for an hour with no sign
of setting, or a cream has been stirred and
stirred with no sign of thickening. But there’s
good reason to resist. The gentler these dishes
are heated, the greater the safety margin