eight hours releases only about 20% of the
gelatin in beef bones, the bones may be
extracted for a second time, for a total of up to
24 hours. The resulting liquid can then be
used to start the next fresh extraction of meat
and bones.
Concentrating Meat Stocks: Glace and
Demi-glace Slowly simmered until it’s
reduced to a tenth its original volume, stock
becomes glace de viande, literally “meat ice”
or “meat glass,” which cools to a stiff, clear
jelly. Glace has a thick, syrupy, sticky
consistency thanks to its high gelatin content,
about 25%, an intensely savory taste thanks to
the concentrated amino acids, and a rounded,
mellow, but somewhat flat aroma thanks to
the long hours during which volatile
molecules have been boiled off or reacted
with each other. Meat glace is used in small
quantities to lend flavor and body to sauces.
Intermediate between stock and glace is demi-