This section is from the book "Cassell's Cyclopaedia Of Mechanics", by Paul N. Hasluck. Also available from Amazon: Cassell's Cyclopaedia Of Mechanics.
Malt might be made in small quantities from barley, but care is required. The barley is soaked in water for from forty-eight to seventy-six hours, according to the time of the year. It is placed in heaps till it becomes dry to the touch, the temperature rising by the growth of the barley: after about ninety-six hours the heat has risen to the full, and the acrospire or young shoot is visible on splitting the grain. The heaps are now spread flat on the floor and turned over about twice each day, the temperature of the rooms being about 60° F. The young shoot appears from the barley in a few days and dries away after about twelve days. The malt is now moved to the kilns and spread in layers, the heat varying with the kind of malt required - for pale malts 900 to 1600 F., rising to 115° to 165° F. The heating in the kiln requires one or two days. In mashing the malt with water, the water is previously heated to 1600 to 1700 F.; it is not necessary to keep that temperature up for long, but it may be allowed to fall slowly: on no account should the temperature be allowed to go higher than stated above.