Page:A Practical Treatise on Brewing (4th ed.).djvu/30

14 very advantageous to lay in and kiln-dry a large stock, to be kept for malting the next season. By kiln-drying it will be kept perfectly sound, and will malt as freely or more so than new barley; and should the season prove unfavourable, such provision will be a considerable saving.

By the same valuable experiments of Messrs. Colin and Edwards upon the germination of different kinds of grain, we are led to suggest that the temperature used for drying the barley should not exceed 122° F., while in drying pale malt, the temperature is frequently as high as 160° or 170°. In the Records of General Science, vol. i. 445, Dr. Thomson states that very pale malt may be dried, although the temperature be brought as high as 175°.

The medium, however, through which the heat is communicated, modifies the range of temperature considerably. Thus the seeds before mentioned, if exposed to a temperature of 143° in air containing vapour, or of 167° in dry air, are deprived of their vegetating properties; and when wheat, oats, or barley, had been kept in sand at 113°, they would not germinate. Immersion in water at 167° for 14 seconds destroyed the power of germination. The grains of starch burst at a temperature of 167° according to Raspail.

In the Ann. de Chimie et de Phys. tom. v., Ann. Philos. xii. p. 201., Proust gives the following comparative analysis of barley and malt: