employed. The more intense the latter, the speedier will be the cooking, while the stirring will of necessity be more rapid. Brown roux is known to be cooked when it has acquired a fine, light brown colour, and when it exudes a scent resembling that of the hazel-nut, characteristic of baked flour.
It is very important that brown roux should not be cooked too rapidly. As a matter of fact, among the various constituent elements of flour, the starch alone acts as the cohering principle. This starch is contained in little cells, which tightly constrain it, but which are sufficiently porous to permit the percolation of liquid and fatty substances. Under the influence of moderate heat and the infiltered butter, the cells burst through the swelling of the starch, and the latter thereupon completely combines with the butter to form a mass capable of absorbing six times its own weight of liquid when cooked.
When the cooking takes place with a very high initial heat the starch gets burned within its shrivelled cells, and swelling is then possible only in those parts which have been least burned.
The cohering principle is thus destroyed, and double or treble the quantity of roux becomes necessary in order to obtain the required consistency. But this excess of roux in the sauce chokes it up without binding it, and prevents it from despumating or becoming clear. At the same time, the cellulose and the burnt starch lend a bitterness to the sauce of which no subsequent treatment can rid it.
From the above it follows that, starch being the only one from among the different constituents of flour which really effects the coherence of sauces, there would be considerable advantage in preparing roux either from a pure form of it, or from substances with kindred properties, such as fecula, arrowroot, &c. It is only habit that causes flour to be still used as the cohering element of roux, and, indeed, the hour is not so far distant when the advantages of the changes I propose will be better understood—changes which have been already recommended by Favre in his dictionary.
With a roux well made from the purest starch—in which case the volume of starch and butter would equal about half that of the flour and butter of the old method—and with strong and succulent brown stock, a Spanish sauce or Espagnole may be made in one hour. And this sauce will be clearer, more brilliant, and better than that of the old processes, which needed three days at least to despumate.
