purees. But both are marvels of mouth-filling
pleasure.
Sauces Thickened
with Droplets of Oil
or Water: Emulsions
The sauces we’ve examined so far are liquids
thickened with a fine dispersion of solid
materials: protein molecules, starch granules
and molecules, particles of plant tissue and
cell-wall molecules. A very different
thickening method is to fill the water-based
liquid with droplets of oil, which are much
more massive and slow-moving than
individual molecules of water, impede their
motion, and so create a thick and creamy
consistency in the mixture as a whole. Such a
dispersion of one liquid in another is called an
emulsion. The word comes from the Latin for
“to milk out,” and referred originally to the
milky fluids that can be pressed from nuts and