B

1. The steep is a square cistern, sunk at one end of the malt barn, lined with stone, and of a sufficient size to hold the whole barley that is to be malted at a time. The barley is put into this cistern with the requisite quantity of pure water to cover it. It is laid as evenly as possible upon the floor of the cistern. Here it must remain at least forty hours; but in Scotland, especially when the weather is cold, it is customary to allow it to remain much longer. We have seen barley steeped in Edinburgh for 112 hours by one maltster, and by another usually ninety-eight or ninety-two hours. It is the common practice to introduce the water into the cistern before the barley, and it is usually once drawn off and new water added during the steeping,

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 skin 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 varies according to the goodness of the barley, and the length of time during which it is allowed to remain in the steep. But the general average may be stated at 0-47; or 100 lbs. of barley, steeped the usual time, weigh, newly taken out of the steep and dried,

147 lbs, English barley acquires mare weight than Scotch barley, while Scotch barley acquires greater weight than big. But big cannot safely 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 treatise gives the bulk of one hundred measures of different kinds of barley, after steeping, as follow:—

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 the county of Suffolk ; the smallest was from 100 to 109, which took place in Perth big.

The average increase of the bulk of barley, when steeped for forty hours,is 0-222; or 100 barley becomes 122*2. This is very nearly in the proportion of 9 to 11. In charging the duty the swell of the grain is accounted for to the above amount. If the swell exceeds, and the malt carries the excess through the check-gauges on the floor until the malting is finished, a proportional duty is charged above the quantity of barley when first steeped. If the swell is much under the proportional of 11 to 9, and the gauges on the floor and kiln correspond, the duty is charged under the quantity of barley. English barley seldom comes below the standard; but Scotch barley, except of very fine quality, is generally below it

While the malt is in the steep-cistern it is repeatedly 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" exceeds the best gauge in the cistern, to levy the duty by it. But these subsequent gauges are not susceptible of the same precision as the gauges in the cistern, 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 experiments. If the steep-water be mixed with lime-water, 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 remain rather too long without being changed. In these cases, something like a commencement of fermentation, 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 extricated from the water in an imperceptible manner. From the observations of Saussure, it seems probable that t^e 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 colour, and the peculiar smell and taste of water in which straw has been steeped. At the same time, the barley becomes whiter, shewing clearly that the water has absorbed a portion of colouring matter which existed in the husk or skin of the grain. The average quantity of matter dissolved by the water amounts to about TVth of the weight of the barley. The steep-water becomes much more deeply coloured when big is steeped in it than it does with barley, because big is darker in the colour, 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 matter of a yellow colour and disagreeably bitter taste, which deliquesces in a moist atmosphere. The only salt which it contains in any notable quantity is nitrate 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 mat ter 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.

2. When the barley is judged by the maltster to have remained long enough in the steep, which is the case when its two ends can be easily squeezed together between the finger and the thumb, the water is let off and the grain allowed to drain. It is then thrown out of the cistern into the couch, which is formed of moveable wooden boards placed by the side of the cistern, and where the wetted barley can be gauged by the excise-officer with the greatest accuracy. While in this position, if it measure more than it did in the steep, the exciseman is at liberty to charge the duty upon the quantity to which the grain now amounts. The duty, we believe, is levied from the couch-gauge. The grain is allowed to remain in the couch without any alteration for about twenty-six hours.

3. If we plunge a thermometer into the grain, and observe it from time to time, we shall find that the barley continues for some hours without acquiring any perceptible increase of heat. During this period the moisture on the surface of the corns gradually exhales or is absorbed, so that they do not perceptibly moisten the hand. But at last the thermometer begins to rise, and continues to do so gradually till the temperature of the grain is about ten degrees higher than that of the surrounding atmosphere. This happens usually in about ninety-six hours after it has been thrown out of the steep. It now exhales an agreeable odour, which has some resemblance to that of apples. If we thrust our hand into the heap we shall- find that it feels warm, while, at the same time, it has become so moist as to wet the hand. The appearance of this moisture is called sweating by the maltsters, and it constitutes a remarkable period in the process of malting. We havfe reason to believe that a little alcohol is at this period exhaled by the grain.

If we examine the grains in the inside of the heap at the time of sweating, we shall perceive the roots beginning to make their appearance at the bottom of each seed. At first they have the appearance of a white prominence, which soon divides itself into three rootlets. In big the number of rootlets seldom exceeds three, but in barley it frequently amounts to five or six. These rootlets increase in length with great rapidity, unless their growth be -checked by artificial means; and the principal art of the maltster is directed to keep them short till the grain be sufficiently malted. The writer of this treatise has seen them increase in length nearly two inches in the course of a single night; and when he purposely favoured the growth, in order to ascertain the effect upon the malt, he has seen them get to the length of three inches or more. In such cases, the heat of the grain rose very rapidly, and on one occasion was little inferior to eighty degrees. Indeed it is probable that, if not checked, the temperature would rise sufficiently high to char the grain, if not to set it on fire.

The too great growth of the roots, and the too high elevation of temperature is prevented by spreading the grain thinner upon the floor, and carefully turning it over several times a-day. At first the depth is about sixteen inches; but this depth is diminished a little at every turning, till at last it is reduced to three or four inches. The number of turnings is regulated by the temperature of the malt, but they are seldom fewer than two each day. In Scotland, the temperature of the grain is kept as nearly as possible at fifty-five degrees; but in England we have generally found the temperature of the grain on the malt-floor about, sixty-two degrees. It has been generally supposed that the Hertfordshire method of making malt is the best; but, after a very careful comparison of the two methods, we were unable to perceive any superiority whatever in the English mode.

About a day after the sprouting of the roots, the rudiment of the future stem begins to make its appearance. This substance is called by the maltsters the acrospire. It rises from the same extremity of the seed with the root, and, advancing within the nusk or skin, would at last (if the process were con tinued long enough) issue from the other extremity in the form of a green leaf; hut the process of malting is stopped before the acrospire has made such progress.

While the grain is on the malt-floor, it has been ascertained that it absorbs oxygen gas, and emits carbonic acid gas ; but to what amount these absorptions and emissions take place, has not been ascertained. They are certainly small; for the .average loss which the grain sustains when on the malt-floor is only three per cent.; a considerable portion of which must be ascribed to roots broken off, and grains of barley bruised during the turning. As the acrospire shoots along the grain, the appearance of the kernel, or mealy part of the corn, undergoes a considerable change. The glutinous and mucilaginous matter in a great measure disappears, the colour becomes whiter, and the texture of the grain so loose that it crumbles to powder between the fingers. Thte object of malting is to produce this change. When it is accomplished, which takes place when the acrospire has come nearly to the end of the seed, the process is stopped altogether.

At this period, it was formerly the custom in Scotland to pile up the whole grain into a pretty thick heap, and allow it to remain for some time. The consequence is the evolution of a very considerable heat, while, at the same time, the malt becomes exceedingly sweet. But this plan is now laid aside, because it occasions a sensible diminution in the malt, with-

c out being of any essential service; for the very same change takes place afterwards, while the malt is in the mash-tun, without any loss whatever.

The time during which the grain continues on the malt-floor varies according to circumstances. The higher the temperature at which the grain is kept, the more speedily it is converted into malt. In general, fourteen days may be specified as the period which intervenes in England from throwing the barley out of the steep till it is ready for the kiln; while in Scotland it is seldom shorter than eighteen days, and sometimes three weeks. This, no doubt, is an advantage in favour of English malting, as every thing which shortens the progress, without injuring the malt, must turn out to the advantage of the manufacturer.

4. The last part of the process is to dry the malt upon the kiln, which stops the germination, and enables the brewer to keep the malt for some time without injury. The kiln is a chamber, the floor of which usually consists of iron plates full of holes, and in the roof there is a vent, to allow the escape of the heated air and vapour. Under this room is a space in which a fire of charcoal or coke is lighted. The heated air which supplies this fire passes up through the holes in the iron plates, and makes its way through the malt, carrying off the moisture along with it. At first the temperature of the malt is not higher than 90°; but it is elevated very slowly to 140°, or even higher. We believe that in many cases it rises at last almost as high as 212°, though we have never witnessed any such high temperature ourselves. But we have seen pale malt dried at a temperature of 175°, without any injury whatever. The great secret in drying malt properly consists in keeping the heat very low at first, and only raising it very gradually, as the moisture is dissipated. For a high temperature applied at first would infallibly blacken or even char the malt, and would certainly diminish considerably the quantity of soluble matter which it contains. We shall here insert the table drawn up by Mr Combrune, from his own experiments, of the colour of malt dried in different temperatures.

Heat.

0 0

Post a comment