Mr Comhrune's law, however, that the heat of the water in mashing ought to be regulated by the colour of the malt ; namely, that the paler the malt is, the' lower ought the temperature of the mashing water to be, is founded on accurate observations. The fact is, that boiling water would answer better than any other for mashing, because it would dissolve most speedily the soluble part of the malt. The only reason for not using it is, that the tendency of the malt to set increases with the temperature of the water. Now, the higher the colour of the malt, the less is its tendency to set; of course, we may use water of a higher temperature to mash with it. For the same reason, when raw grain is used, the temperature of the mashing water must be still lower than when malt is employed ; because raw grain has a very great tendency to set.
The old malt-kilns had a bottom of hair-cloth in stead of the iron plates full of holes, which constitute a more recent improvement. We hare seen the thermometer in such a kiln, when the bulb touched the hair-cloth, rise as high as 186°. In general, the temperature of the malt-lcila is very carelessly re gulated. We have seen malt fiw the very same per: pose dried at a temperature which never rose higher than 136° ; while a portion of the very same malt, put into another kiln, was heated as high as 186°. But such a careless mode of drying malt is repre heasible, and must be more or less injurious to the brewer. In general, the more rapidly malt is dried the more does its bulk increase. This method, ac cordingly, is practised by those who malt for sale, as is the case with most of the English masters ; because molt is always sold by measure, and not by weight. The brewers would find it more for their interest to buy malt by weight than by measure. In that case, the maltaters would dry their malt at as low a temperature as possible. But this would sig. reify very little, or rather would be advantageous to the brewer; because dried malt soon recovers the moisture lost on the kiln when kept for some time in sacks. And, when malt is dried at a low tempera tare, we are sure that none of it is injured by the fire. It will, therefore, go farther in the production of beer. The time of kiln-drying varies consider ably, according to the quantity of malt exposed to the action of the heat. But when that quantity is not too great, we may estimate the time of kiln. drying, in general, at two days. After the fire is withdrawn, the malt is allowed to remain on the kiln till it has become nearly cold.
By the roots of the barley, or, as the maltsters call them, the comings, are dried up and fall of They are separated from the malt by passing it over the surface of a kind of wire-screen, which allows the comings to drop through, while the wires are Ioo near each other to permit the grains of malt to pass.
If 100 lbs. of barley malted in this manner, with all the requisite care, be weighed just after being kiln-dried and cleaned, they will be found, on an average, to weigh 80 lbs. But if the raw grain be kiln-dried at the same temperature as the malt,. It will lose 18 per cent. of its weight. Hence 12 per
cot. of the loss whikh barley sustains in making, must be ascribed to moisture dissipated by the kiln drying ; so that the real loss of weight which barley sustains when malted, amounts to 8 per emit. This toes, from a great many trials made in the large way, with all the requisite care, we conceive may be ac counted for in the following manner : These numbers were obtained from above thirty different makings, conducted in four different malt ing-houses, with as much attention to every circum stance as was compatible with practical malting. The matter carried off by the steep-water, which amounts to about of the weight of the whole grain, we conceive to be dissolved from the skin or husks. It may, therefore, be left out of view. The waste is owing to grain, of malt crushed by the workmen while turning the malt on the floor, and afterwards dissipated or destroyed during the subse quent processes. We were not able to collect these bruised grains and weigh them ; the number there fore given for them in the preceding table is hypo thetical ; but from a great many circumstances, which it would be too tedious to adduce here, we believe that, in our trials, part of the whole very !featly represents the amount of the crashed grains. Thus the real loss of weight by making (supposing nothing lost by steeping, and no grains crushed) is only 6 per cent. and of this loss 4 pr cent. may be safely ascribed to the roots ; so that not above 2 per cent. at most can be assigned to the Oarbon dissipated by the evolution of carbonic acid on the floor, and on the kiln. Indeed we have rea son to conclude, from a good many trials, that the greatest part oithis loss of 2 per cent. is sustained on the kiln. For, if malt dried carefully at a low tat• perature be afterwards kiln-dried, or exposed (as was our method) to the heat of a steam bath, it never afterwards recovers its former weight by ex. posure to the air. And every time this experiment is repeated, by artificially moistening and drying the same malt, a new' oss of weight is sustained. The same observation was made by Saussure, who con ceived that the lose was to be ascribed to the forms lion and dissipation of water in the barleycorn. But we have no proof that aoy sueli formation takes place. It is more probable thst the loss is owing to the formation aad escape of carbolic sad . Big sustains a considerably greater loss of weight when malted than barley. The average loss of weight in our trials with barley was only 8 per cent., while that of big was 15 per cent., or nearly double. This we conceive is owing to the destruction of a much greater number of the corns the pro cess of malting big than barley. But, in all our experiments on big, that grain was manifestly over steeped. To this, perhaps, a good deal of the dif ference may be ascribed. Our molesters had not been in the habit of malting big, and therefore were not likely to do it so much justice as they did to the barley. Hence it would he improper to yen- ture upon any general conclusions from the experi ments which we made upon the making of big.