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PHYSICAL FACTORS AFFECTING THE KILNING OF BARLEY AND MALT
Author(s) -
Johnston J. H. St.
Publication year - 1954
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1954.tb02759.x
Subject(s) - humidity , moisture , volume (thermodynamics) , environmental science , kiln , shrinkage , relative humidity , atmospheric pressure , materials science , thermodynamics , composite material , meteorology , geography , metallurgy , physics
The main physical factors affecting the kilning of barley and malt are the quantity of moisture to be removed, the temperature and humidity of the air entering and leaving the kiln, the temperature to which the air is heated, the hygroscopic state of the grain and the volume of air passing. The effect of weather on natural draught kilns can be expressed in an arbitrary Drying‐Power Table. The hygroscopic state of barley or malt has been measured by determining the vapour pressures at various stages of kilning. Restriction of vapour pressure due to shrinkage of internal pores begins in barley at about 17% and in malt at about 12% moisture content. Knowing the degree of such restriction, it is possible using the Mollier Diagram to calculate the theoretical volume of heated air required at any stage of kilning and hence the theoretical fuel consumption. With suitable recording instruments, the actual volumes of heated air passing can be measured and the loss of efficiency due to imperfect saturation of the out‐going air, and to heat losses, etc., can be determined. Draught control, combined if possible with recirculation of heated air during curing, is the principal factor affecting fuel economy.