The Chemistry of Cookery

description than ‘partly soluble’ (Miller) or ‘very slightly soluble’ (Lehmann). This difference is not merely a verbal quibble, but very real and practical in reference to the _rationale_ of its cookery. A partially soluble substance is one which is composed of soluble and also of insoluble constituents, which, as already stated, is strictly the case with gluten in reference to the solvent action of hot alcohol. A very slightly soluble substance is one that dissolves completely, but demands a very large quantity of the solvent. I find that the action of hot water on gluten, as applied in cookery, is to effect what may be described as a partial solution—that is, it effects a loosening of the bonds of solidity without going so far as to render it completely fluid. It appears to be a sort of hydration similar to that which is effected by hot water on starch, but less decided. To illustrate this, wash some flour in cold water so as to separate the gluten in the manner already described; then boil some flour as in making ordinary bill-stickers’ paste, and wash this in cold water. The gluten will come out with difficulty from this, and, when separated, will be softer and less tenacious than the cold-washed specimen. This difference remains until some of the water it contains is driven out, for which reason I regard it as hydrated, though I am not prepared to say that the hydration is of a truly chemical character—a definite chemical combination of gluten with water; it may be only a mechanical combination—a loosening of solidity by a molecular intermingling of water. The importance of this in the cookery of grain-food is very great, as anybody who aspires to the honour of becoming a martyr to science may prove by simply making a meal on raw wheat, masticating the grains until reduced to small pills of gluten, and then swallowing them. Mild indigestion or acute spasms will follow, according to the quantity taken and the digestive energies of the experimenter. Raw flour will act similarly, but less decidedly. Bread-making is the most