It is in very many instances desirable that a similar arrangement should be provided, in other countries than Bavaria ; for during the summer months the high atmospheric temperature pre yenta, to a great extent, successful brewing of the beet kinds of malt liquor, and loss of time is occasioned to the brewer. With a view of affording a more perfect control over the process of fer mentation, Barclay Walker, of Warrington, deaigned an atmospheric tun-room attemperator. It consists of a fan, by the aid of which a supply of air is forced to traverse a number of flattened tubes immersed in cold water, or aurrounded by ice or a freezing mixture; the air, after being thus cooled, is led off by pipes extending over the range of tuns in the tun room. From the pipes, branches are led down into the tuns, these branches being furnished at their lower ends with perforated roses, whieh distribute the cold air a short distance above the aurface of the wort. Each branch is fur nished with a slide, so that the supply of air to each tun can be regulated. By this arrangement, the temperature of the air above the aurfaee of the fermenting wort can be kept at that point which produces the best reaults, and a command over the process is given which cannot be obtained under ordinary eireumstancea.
Where yeast cannot be got by exchange, it may be originated from a mixture consisting of 14 lb. of grated potatoes, a similar quantity of molasses, coarse sugar, or honey, mixed with 3 gallons of water at a temperature of 21° to 24° (70° to 75° F.). This mixture should bo set in a warm place until it ferments, and then mixed into three times its quantity of freah first wort from the mash tun. This yeast is often made by distillers, and is known under the term of " bub.'' When the brewer is compelled to use bub, he ought to employ it on a small brew, to raise berm for future brews. The quantity propoaed will ferment 40 or 50 barrels.
It may be here recapitulated that in the best practice good brewing dependa upon careful malt ing, so as to have the malt always in the same condition of freely yielding the extract required from it. Careful curing of the malt on the kiln at the time of drying, and storing it in suitable backs, so as to retain the properties acquired in the kiln. To keep these backs of a, size that when opened will allow of their contents being used, before the malt loses its curing, or suffers the slightest decomposition ; the only alternative being to re-cure the malt so that it may be sound when it comes to the mash tun. In mashing, to wet the malt first into a thick mash within the point of the ultimate temperature, so far as to allow the variationa in the heat of the malt under use to expend itself within the given ultimate temperature, and thus prevent the setting of the mashes, and the passing to the fermenting tun of pasty, unconverted materials that may afterwards decompose in the beer. This wetting proeesa should produce a homogeneous temperature of 65° (150° F.), and
immediately after thia wetting hotter water should be turned on, and the mashing rakes started to bring the temperature to 69° (156° F.).
The mash, after standing one hour and three-quarters, should have the aparge temperature regulated, to keep the goods at 69° for two and a half to three hours from the time of setting the tap ; and if the goods are not extracted by this time, the water must be lowered in temperature 10° or 14° (20° or 30° F.) or more, if necessary, to bring the goods in the tun to 65° by the time the extraction is complete. In mashing, time and temperature may be considered nearly synony mous terms ; preponderance of beat should be compensated by reduction of the time during which the goods are exposed. In aparging, if the goods heat rises to 70° (158° F.), or even 71°, the sparge-water temperature should be lowered for the fint half hour, or for a whole hour, aooner than the three hours given as a standard period of high heat exposure, so that the goods will have been brought to 65° at the end of the precesa. If second mash and a sparge be the method followed, the second mash heat may be 69°, like the first, but the sparging to fullow ought to lower the mash apparatus gradually to 65° at the end of the mash; and if a third or fourth mashing must be taken, neither ought to make the gooda over 65°.
Vatting and Fining.—It was formerly the practice of the London brewers to keep immense stocks of their porter in store for eighteen months or two years. The atore vats, some of which were of enormous size, were made of well-seaaoned oak strongly hooped, and their heads were covered with sand, so as to exclude the air as much as possible. At the present time, the practice of vatting beer for long periods is not followed.
At numerous breweries, it is the practice to pump or run the beer from the cleansing rounds to settling tanks or racking squares, and after allowing it to deposit any floating matters, to draw it off direct into casks. In casking pale ale, from lb. to lb. of fresh choice hops a barrel is added; these hops materially assist in keeping the ale, and also impart to it a fine aroma. Stock ales also receive about 1 lb. of hops a barrel when casked. The pale ale should be kept in cask at least six months before being consumed, and if well brewed it may be kept from twice to three times that period with advantage. London porter now seldom remains in a vat more than a month, and as a rule it is stored only for a day or two. The change effected in beer by storing it in close vessels appears to be due to an insensible fermentatioo, which goes on for a considerable time, resulting in the impregnation of the liquor with carbonic acid gas. Ure considers that the quality of the beer never remains stationary when in the store vats, and tbat from the moment it ceases to improve it begins to deteriorate by acetic fermentation.