Three changes take place on the barley while in the steep. 1. It imbibes moisture, and increases in bulk. 2. Some carbonic acid gas is evolved, most of which remains dissolved in the steep-water. 3. A portion of the husk or ekia of the barley is dissolved, in consequence of which the steep-water acquires a yellow colour, and contracts a peculiar smell, not unlike that of moist straw.
The quantity of moisture imbibed by the barley 1 varies according to the goodness of the barley, and' the length of time during which it is allowed to re main in the steep. But the general average may be stated at 0.47 ; or 100 lbs. of barley, steeped the usual time, weigh, when newly taken out of the steep and dried, 147 lbs. English. barley acquires more weight than Scotch barley, while Scotch barley ac quires greater weight than big. But big cannot bear to be steeped for so long a time as barley. The swell of the grain in the steep obviously depends upon the quantity of water absorbed ; but it is not so great as that absorption, scarcely ever exceeding one-fifth of the original bulk of the barley, while the increase of weight amounts to nearly one-half of that of the original weight of the grain. The result of a good many trials by the writer of this article, gives the bulk of 100 measures of different kinds of barley, after steeping, as follows : English barley - 124 measures Scotch barley - 121.1 Scotch big • - 118.
The greatest swell observed was from 100 to 183, which took place in barley from County of Suf folk ; the smallest was from 100 to 109, which took place in Perth big.
While the malt is in the steep cistern, it is repeat. edly gauged by the Exciseman, and the duty on the malt is levied by what is called the best gauge, or that which gives the greatest bulk of grain. It is in his power likewise to determine the quantity of malt in the subsequent processes, and if any of them ex ceeds the best gauge in the cistern, to levy the duty by it, But these subsequent gauges are not suscep tible of the same precision as the gauges in the cis tern, when the grain is surrounded on all sides by perpendicular walls.
That carbonic acid is evolved during the steeping of grain, is obvious from the most simple experi ments. If the steep-water be mixed with lime-wa ter, the whole becomes milky, and carbonate of lime is deposited. If the steep-water be agitated, it
froths on the surface like ale. If it be heated, it gives out carbonic acid gas, which may be collected over mercury. But we never were able to observe bubbles of gas extricate themselves from the grain during the steep, except once or twice during warm weather, when the steep-water was allowed to re main rather too long without being changed. In these cases, something like a commencement of fermenta tion, or perhaps of putrefaction, appeared to take place. But, in general, there is reason to believe, that nearly all the carbonic acid evolved in the steep remains in solution in the water, or at least is extri cated from the water in an imperceptible manner. From the observations of Saviour% it seems proba ble, that the formation of carbonic acid in the steep is owing to the oxygen gas held in solution by the steep-water.
The steep-water gradually acquires a yellow co lour, and the peculiar smell and taste of water in which straw has been steeped. At the same time, the barley becomes whiter; showing clearly that the water has a portion of colouring matter which existed in the husk or skin of the gram. The average quantity of matter dissolved by the water amounts to about -th of the weight of the barley. The steep-water becomes much deeper coloured when big is steeped in it than it does with barley; because big is darker coloured, and its husk is thicker, and contains more colouring matter. The matter of big taken up by the steep-water amounts to about of the weight of the whole grain. When this steep-water is evaporated, it leaves a mat ter of a yellow colour and disagreeable bitter taste, which deliquesces in a moist atmosphere. The only salt which it contains in any notable quantity is ni trate of soda.
Thus the only notable alterations which the kernel of barley undergoes in the steep are the absorption of water, and the resulting increase of bulk. The matter taken up by the water seems to proceed only from the skin, and the evolution of carbonic acid may, perhaps, be owing to some commencement of alteration which this dissolved matter experiences. It can scarcely be ascribed to any change going on within the kernel itself.