ON ROUX

"The assistant of the stock, the roux, brings to the brown sauce only a flavor note of little importance, beyond its thickening principle, and it has the disadvantage of requiring, in order that the sauce be perfect, an almost absolute elimination of its components. Only the starchy principle remains in a sauce properly skimmed. Indeed, if this element is absolutely necessary to give mellowness and velvetiness to the sauce; it is much simpler to give it pure, which permits one to bring it to the point in as little time as possible, and to avoid a too prolonged sojourn on the fire. It is therefore infinitely probable that before long starch, fecula, or arrowroot obtained in a state of absolute purity will replace flour in the roux."

August Escoffier