On Food and Cooking

somewhat smaller, and a powerful industrial
homogenizer can reduce them to less than one
thousandth of a millimeter. The size of the
droplets matters, because smaller droplets are
less likely to coalesce with each other and
break the sauce into two separate phases
again. They also produce a thicker, finer
consistency, and seem more flavorful because
they have a larger surface area from which
aroma molecules can escape and reach our
nose.
Two factors make it easier for the cook to
generate small droplets. One is the thickness
of the continuous phase, which drags harder
on the droplets and transfers more shearing
force to them from the whisk. Shake a little
oil in a bottle of water, and the oil droplets are
coarse and quickly coalesce; shake a little
water in the more viscous oil, and the water
gets broken into a persistent cloud of small
droplets. It’s helpful, then, to start with as
viscous a part of the continuous phase as