forms crystals around 85ºF/30ºC, and the
crystals poke through the thin membrane of
emulsifiers and fuse with each other, forming
a continuous network of fat that separates
when the sauce is reheated. Ideally, beurre
blanc should be kept at around 125ºF/52ºC.
Because water will evaporate at this
temperature and may overconcentrate the fat
phase, it’s a good idea to add a little water
periodically if the sauce has to be held for any
time.
Beurre Monté A preparation closely related
to beurre blanc is beurre monté, “worked up”
or “prepared” butter, which is simply an
unflavored beurre blanc made with an initial
dose of water rather than vinegar or wine.
Beurre monté is used among other things as a
poaching medium. Thanks to the relatively
low heat conductivity and heat capacity of fat
compared to water, it cooks delicate fish and
meats more gradually than does a broth at the