BREWING, the art of brewing, or of preparing a vinous fermented liquor from the farinaceous seeds, is of very high an tiquity. The ancient Egyptians, from the soil and climate of their country not being favourable to the culture of the vine, were induced to seek a substitute in barley, from which, in all probability, by the process of malting, they knew how to procure a fermented liquor. All the an cient malt liquors, however, seem to have been made entirely of barley, or some other farinaceous grain, and therefore were not generally calculated for long keeping, as this quality depends consi derably, though not entirely, on the bit ter extract of hops, or other vegetables, with which the liquor is mingled. Mo dern malt liquor is essentially composed of water, of the soluble parts of malt and hops, and of yeast.
Three or four different kinds of malt are distinguished by the brewer by their colours, which depend on the degree of heat that is used in the drying. Malt that has been dried by a very gentle heat scarcely differs in its colour from barley ; if exposed to a somewhat higher tempe rature, it acquires a light amber-yellow hue ; and by successive increments of heat, the colour becomes deeper and deeper, till, at length, it is black. The change of colour is owing to the grain being partially charred or decomposed ; and in proportion to the extent to which this alteration is allowed to proceed will the produce of sugar, that is, of ferment able matter, be diminished. The princi pal advantage of high-dried malt over the paler kind is, the deep yellowish-brown tinge which it gives to the liquor ; but this colour may be communicated much more economically by burnt sugar. The malt, whether pale or high dried, must be bruised between rollers, or coarsely ground in a mill before it is used ; and it is found by experience, that malt which has lain to cool for some weeks is, in ma ny respects, preferable to that which is used as it comes hot from the mill. The first step in the process of brewing is Mashing. This is performed in the mash-tun, which is a circular wooden ves sel, shallow in proportion to its extent, and furnished with a false bottom, pierced with small holes, fixed a few inches above the real bottom : when it is small, it ought to have a moveable wooden co. ver. There are two side openings in the interval between the real and false bot toms; to one is fixed a pipe, for the pur pose of conveying water into the tun : the other is fitted with a spigot, for the purpose of drawing the liquor out of the tun. The brewing commences by strew ing the grist or bruised malt evenly over the false bottom of the mash-tun, and then, by means of the side pipe, letting in from the upper copper the proper quantity of hot water. The water first fills the interval between the two bottoms, then, forcing its way through the holes in the false bottom, it soaks into the grist, which, at first floating on the surface of the water, is thus raised off the bottom, on which it was spread. When the whole
of the water is let in, the process of mashing, properly so called, begins. The object in mashing is, to effect a perfect mixture of the malt with the water, in order that all the soluble parts may be extracted by this fluid : for this purpose, the grist is first incorporated with the water by means of iron rakes, and then the mass is beaten and agitated, and still further mixed by long flat wooden poles, resembling oars, which indeed is thename by which they are technically known. In some of the large porter breweries, the extent of the tun is so great, that the pro cess of mashing cannot be adequately performed by human labour, and re course is had to a very simple and effec tual instrument for this purpose. A very strong iron screw, of the same height as the mash-tun, is fixed in the centre of this vessel, from which proceed two great arms or radii, also of iron, and beset with vertical iron teeth a few inches asunder, in the manner of a double comb ; by means of a steam engine, or any other moving power, the iron arms, which at first rest on the false bottom, are made slowly to revolve upon the central screw, in consequence of which, in proportion as they revolve, they also ascend through the contents of the tun to the surface : then, inverting the circular motion, they descend again in the course of a few revo lutions to the bottom. These alternate motions are continued till the grist and water are thoroughly incorporated. When the mashing is completed, the tun is co vered in, to prevent the escape of the heat, and the whole is suffered to remain still, in order that the insoluble parts may separate from the liquor : the side spigot is then withdrawn, and the clear wort is allowed to run off, slowly at first, but more rapidly as it becomes fine, into the lower or boiling copper. The principal thing to be attended to is the tempera ture of the mash, which depends partly on the heat of the water, and partly on the state of the malt. If any quantity of barley is mingled with twice its bulk of water, the temperature of the mass will be very nearly that of the mean tempera ture of the ingredients. If the palest malt is subjected to the same experiment, the temperature will be somewhat greater than that of the mean heat. The most eligible temperature upon the whole for mashing appears to be about 185° to 190° of Fahrenheit : the heat of the water, therefore, for the first mashing, must be somewhat below this temperature, and the lower in proportion to the dark co lour of the malt made use of. Thus, for pale malt, the water of the mash may be at 180° and upwards : but for high-dried brown malt, it ought not much to exceed 170°.