temperatures, surface tension increases,
making it more likely that neighboring
droplets will coalesce. Butterfat
solidifies at room temperature, and some
oils do so in the refrigerator. The
resulting sharp-edged fat crystals rupture
the layer of emulsifier on the droplets, so
that they coalesce and separate when
stirred or warmed. Refrigerated
emulsions often need to be reemulsified
before use. (Manufactured mayonnaise is
made with oils that remain liquid at
refrigerator temperatures.)Rescuing a Separated Sauce When an
emulsified sauce breaks and the droplets of
the dispersed phase puddle together, there are
two ways to reemulsify it. One is simply to
throw the sauce in a blender and use its
mechanical power to break the dispersed
phase apart again. This generally works for
sauces that still have plenty of intact