The essence of beef of commerce is well known.
To make essence of beef used in cooking and called _glace_ in French,
set three or four quarts of broth on a slow fire, in a saucepan and
reduce it to jelly. Keep it simmering all the time; it may take twenty
hours to reduce. When properly reduced, it is of a very dark-brown
color and has a very pleasant odor.
When cold, it must be rather hard.
When essence of beef tastes like glue and has an unpleasant odor, it is
not made properly, or with good beef.
If properly made, it will keep any length of time.
It is used to thicken sauces, to decorate boned birds, etc.; when in a
hurry, it may be used to make soup, but, like every thing preserved, is
of course inferior to fresh broth.