separating, or the proteins coagulating and
curdling.
Whole milk is only about 4% fat, so its fat
globules are too few and far between to block
the flow of the water phase and give much of
an impression of thickness. Cream is a portion
of milk in which the fat globules have been
concentrated and crowded: light cream is
around 18% fat, and heavy or whipping cream
around 38%. In addition to its fat supply,
cream offers proteins and emulsifying
molecules that can help stabilize other, more
fragile emulsions (beurre blanc).
Heavy Cream Resists Curdling The casein
proteins in milk and cream are stable to
boiling temperatures, but they’re sensitive to
acidity, and the combination of heat and acid
will cause them to curdle. Many sauces
include flavorful acid ingredients: sauté pans
are often deglazed with wine, for example.
This means that most milk and cream