Page:Encyclopædia Britannica, Ninth Edition, v. 4.djvu/311

and the scar or eye, through which the seed is nourished during the process. The hard white part is termed, botani- cally, albumen. This is the cotyledon, and forms the chief part of the seed, supplying the germ with food during the first few days of its existence. With the germ, which begins to exist within an hour of being put in steep, springs also into existence the principle termed diastase. This name (from Siumj/ii, to separate) was given it by MM. Payen

and Persoz, who made numerous experiments with it.

According to Muspratt, diastase may be obtained by making a paste of malted grain at a temperature of 76, allowing it to stand for a few minutes, and then pressing out the liquor, which is afterwards filtered and heated in a water bath at 170. At this temperature a portion of the foreign nitrogenous matter coagulates, which is after wards separated by filtration. Tho clear filtrate, which contains tolerably pure diastase, is evaporated at a low temperature to dryness. Diastase is not only soluble itself, but has the power of dissolving starch, and converting it into soluble gum, to which is given the name dextrin, and finally into grape sugar, so called because, on analysis, it closely resembles the sugar which naturally exists in the grape. So powerful is diastase, that one part will convert 2000 parts of starch into grape-sugar. This operation will be noticed belowunder the head of mashing. It is on account of this wonderful power of diastase to convert starch into saccharine matter, that distillers use one part of malt in mashing to five parts of raw grain. The next part of the seed that comes under notice is the corcule, which is the embryo of the future plant. This germ, feeding on the sugar formed from the starch of the cotyledon by the action of diastase, grows upwards and downwards, the upward growth being the plumule or " acrospire," the downward the radicle or future root. Acetic acid (vinegar), which does not exist in raw grain in a free state, is now also formed ; this assists the diastase in its action.

The maltster s object is to obtain as much saccharine matter as possible, with the smallest loss of substance, by converting the starch of the barley into sugar, and thus pre paring it for the brewery, where it is changed by fermenta tion into alcohol. Chemically, starch and sugar are com posed of the same elements, carbon, oxygen, and hydrogen ; but their atoms are differently arranged, the mean results of the analyses of Berzelius, Gay-Lussac, and Thenard, giving YQ-jjths of a grain of carbon more in starch than in sugar, whilst sugar contains -j-^ths of a grain more of oxygen and j-j^-ths less of hydrogen than starch.

The duty on malt forms an important item in the revenue, and stringent laws have been made to enable the excise to levy the duty, and prevent the maltster from defrauding. It may be remarked, however, that although those rules were relaxed or abolished, the process of manufacture would be carried on as it is now. The duty was first raised in the reign of Charles I. on the following scale : English malt, 4s. 4d. ; Scotch barley-malt, 3s. 8^-d. ; Scotch bigg-malt, 3s. per bushel, but 2s. of this was a war-tax, and the whole was soon repealed. In 1697 a tax was again imposed (to enable William III. to carry on war with France) of Of d. per bushel. The rate has been frequently changed, and has ranged between 7d. and 4s. 5

Table showing Quantity of Malt made in Great Britain during the years 1871 to 1874, and the amount of Duty levied:—

Year. No. of Bushels. Duty Levied. ENGLAND 1871 46,318,153 6,281,899 From Barley. - 1872 1873 51,511,682 52,873,839 6,986,273 7,171,014 1874 53,661,020 7,277,775 SCOTLAND 1871 2,768,187 375,435 From Barley. 1872 1873 2,956,040 3,171,582 400,913 430,146 1874 2,819,612 382,410 1871 37,843 3,973 From Bigg... 1872 1873 23,636 26,931 2,482 2,828 1874 20,600 2,163 IRELAND ( 1871 2,929,282 397,284 From Barley. < 1872 1873 2,715,412 3,365,624 368,278 456,463 ( 1874 3,221,329 436,893 1871 7,545 792 From Bigg... 1872 1873 7,014 nil. 737 nil. 1874

Malting consists of four processes, steeping, couching, flooring, and kiln-drying,

Steeping is performed in a large cistern of stone, or more

usually brick, covered with cement, into which the barley (properly screened, to remove the small useless grains) is shot from the store-chamber above. It is then levelled and covered with water to the depth of 5 or 6 inches, all floating kernels and refuse being skimmed off. This process is necessary for the germination of the seed not only in a chemical but also in a mechanical point of view. The seed is so hard and compact, and the husk so firmly bound to the kernel, that it would be impossible for the tender germ to make its way through it ; the steeping imparts vitality to the germ, and also assists it in making its way through the husk. The grain now swells about one-fifth in bulk and one-half in weight .from the moisture absorbed; or more pre cisely, 100 Eb of barley would weigh, after steeping, 147 Ib, and 100 bushels measure would increase to 122. By law it has to be kept at least forty hours under water, and fifty if the grain is to be sprinkled before the twelfth day. This time must depend on the kind of barley used, the soil on which it was grown, the heat of the weather, and the hardness or softness of the water in which it is steeped. More time is required in cold than in hot weather. Scotch barley requires more time, but bigg less. Fifty hours steeping will generally suffice, but sometimes seventy is necessary. The rule is if a barleycorn, held lengthwise between the finger and thumb, breaks down into a pulpy, mealy state, the process is complete ; whereas, if the farina exudes in the form of a milky paste, it is over-steeped. In warm, weather the steep-water acquires an odour from matter dissolved out of the barley skin ; and, in consequence of a slight fermentation caused by the organic matter in the water acting on the decayed grain, the water becomes acescent or putrid. The steep-water should then be changed. This the maltster is allowed to do once during each wetting, upon giving due notice to the Excise. Whilst the barley is in steep it is guaged by the excise officers, to prevent fraud, and to calculate the duty to be paid. Wide p 1 uks are placed across the cistern to enable them to take the " dip," sufficient light, and headroom of at least 48 inches, being provided. Numerous experiments show that 81- bushels of good dry barley will, after forty-eight hours steep, swell to exactly 100 bushels. An allowance is

therefore mado of 1 8|- per cent, on the grain found in the