This account of the brewing process is from Philadelphia And Its Manufactures published in 1857:

The following is an outline of the process adopted in the manufacture:-----

Preparatory to the process of Brewing, the barley is converted into malt. This method consists of four processes, viz.: steeping, couching, flooring and kiln-drying. Great care is taken and no expense is spared, to secure the best grain from this and the adjoining States. The grain is first steeped in water contained in wooden or stone cisterns; The water being frequently drawn off and fresh quantity supplied, to cleanse the grain. When sufficiently saturated to admit of its being crushed between the thumb and finger, it is then drained of the water, and spread over a cement floor to a depth of six or eight inches, and left, with occasional turning, until it sprouts.

In the process of germination, a peculiar azotized (sic) substance is evolved, called diastase, which acts as a powerful agent in converting starch into dextrine (sic), and ultimately into saccharine. The maltster continues to turn the barley, at intervals, so as to produce a uniform growth, upon the floors. When the barley has sufficiently sprouted, a stage determined by the sweet taste and chalky appearance of the inside of the grain, it is dried rapidly, in order to retain the starchy matter, which, in a long growth of the sprouts and rootlets, would be wasted. This drying is done in kilns: here heat destroys the germ of the grain, expels the moisture, and converts it into a sweet and friable grain called malt. It is then passed through a cylindrical sieve, separating it from all stones, beans, straws, &c.; and subsequently crushed by rollers. When the brewing is commenced, the ground malt is conducted into a large vat, infused in heated water, and thoroughly mixed by a machine adapted for the purpose : there it remains at rest until the starch is converted into sugar, and then drained into boiling coppers, additional water being sprinkled upon the grain until the saccharine is extracted, which is ascertained by an instrument called the Saccharometer. In these boiling coppers the clear extract, or wort, is boiled with hops, for the purpose of imparting to it an aromatic, bitter flavor, and the property of keeping without injury. This accomplished, it is drained into shallow vessels, and cooled (by an apparatus called a Refrigerator), to the temperature at which the brewer desires the fermentation to commence. Thence it is conducted into a vat, and mixed with yeast of a previous brewing, where the fermentation is carried on. This process continues from three to five days, during which the temperature of the fermenting body rises, and a rapid disengagement of carbonic acid takes place. To prevent the creation of too high a temperature, which would cause acidity of the worts, it is raked off from the fermenting vats into puncheons of one hundred and twenty to one hundred and fifty gallons capacity, where it purges itself of its yeast. The fermentation being now complete, and the Ale or Porter perfectly clear, the sediment or yeast remaining settles at the bottom ; it is racked off from the puncheons into casks of convenient size for use, or stored in large cedar vats for future consumption.