At this period, it was formerly the custom in Scot land 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 consider able heat, while, at the same time, the malt be comes exceedingly sweet. But this plan is now laid aside, because it occasions a sensible diminution in the malt, without being of any essential service. For the very same change takes place afterwards, while the malt is in the mash-tun, without any loss what ever.
The time during which the grain continues on the malt floor varies according to circumstances. The higher at which the grain is kept, the more • y is it converted into malt. In neral, 14 pi be specified as the period which intervenes in England from throwing the barley out of the steep, tillit is ready for the kiln ; while in Scotland, it is seldom shorter than 18 days, and sometimes three weeks. This, no doubt, is an ad vantage in favour of English malting ; as every thing which shortens the progress, without injuring the malt, must turn out to the advantage of the ma nufacturer 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 fire of charcoal or cock is lighted. The heated air which supplies this fire passes up through the boles 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 m oases, 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 experi ments, of the colour of malt dried in different tem peratures.
Hat.
119° - White 126 - Cream-colour 129 - Light yellow 184 - Amber-colour 138 - High amber 143 - Pale brown 148 - Brown 152 - High brown 157 - Brown inclining to black 162 - High brown speckled with black 167 - Blackish brown with black specks 171 -Colour of burnt coffee 176 - Black We have given this table, not on account of any information which it contains, but to put our readers on their guard against the false conclusions of this writer. We have taken malt dried at the tempera ture of 175°, put it into a garden pot filled with soil, and have seen it vegetate apparently as well as raw grain placed in the same situation. Now, this is only one degree lower than that in which Mr Com brune says malt is converted into charcoal, and it is fbur degrees higher than that in which his malt as sumed the colour of burnt coffee. Certainly malt reduced to the splour of burnt coffee by heat, would be deprived of the power of vegetating. Mr Com brunel experiments were made by putting malt into an earthen pan, which he placed over a charcoal fire in a stove, while he kept stirring the malt the whole time of the experiment. The bulb of the thermo meter was placed half-way between the upper sur face of the malt and the bottom of the vessel. Now, the reader will perceive at once, that the earthen pan would be much hotter than that part of the malt where the thermometer was placed. By the constant stifling of the malt, the whole of it was gradually exposed to the burning action ' of the surface of the pan. Had the experiment been made without stirring the malt at all, and bad the thermometer been placed near the surface, in that case, the changes in the colour of the malt at the surface would have indicated the temperature to which it was exposed. But in the way that Mr Combrune conducted his experiments, the tempera tures which he obtained were entirely fallacipus. We have not the least doubt, that the temperature of the earthen pan, towards the end of his experi ment, was above 400°.