The principal points to be taken into consideration in the fermentation of beer, is the weather, the yeast, and the proper performance of mashing.

If the weather is thundery, it is likely to promote acetic fermentation. Warm weather accelerates fermentation, cold weather delays it.

The yeast, if bad, will obstruct the proper fermentation.

If the mashes have been made with too cool liquors, fermentation is difficult, and the wort impoverished; while if the liquor used for mashing was too hot, it will take some time to cure it by fermentation, or it will be "ropy".

The state of the fermentation will soon show any of these faults. If the liquor was too hot, the air bladders on the head of the wort will be as large as a pennypiece. If it was too cool there will be few bladders, and they will be small.

The proper temperature of the wort, when the yeast is put to it, depends on the season of the year. In summer the wort cannot be too cool, in winter it may be as hot as 650, 700, or 750 Fahrenheit.

The temperature of the place in which the ale is to ferment must be also considered, and directed by the thermometer.

Small brewings require more heat than larger ones; and if the outer temperature be very high, the inner must be kept below it. Cold draughts also must be avoided, as they draw off the carbonic acid gas. More yeast is required for fermentation in cold weather than in warm; at least a quarter less will be required in summer.

The method of mixing the yeast is this: Say the wort is by thermometer 6o°; take a pound of yeast to two quarts of wort, stir them well together and place them near the fire for a few minutes, till they begin to ferment; then pour the whole into the fermenting cask, and stir it up with the oar.

The first sign of fermentation is a thin white line round the side of the tun, which gradually creams over the surface. By and by a singing sound is heard from the gas bubbles as they rise to the surface; by degrees the creamy head, growing thicker and thicker, takes the appearance of a cauliflower. At first it is white, then yellow, then brownish-yellow. If the head is in broad flat flakes, something is wrong, or if the air bubbles are of a bluish-white.

When no cauliflower head appears, the wort is said to be unsound, and "to boil." The cauliflower head, when there, grows higher, denser, and closer; the bubbles melt into each other and grow larger, till the head, from which they gradually break and sink, becomes a close brownish mass, and is skimmed off as soon as it shows a tendency to sink. If it iell in, the beer would be bitter.

Fermentation should be gradual, not too quick.

It it does not begin in four or five hours, add a little more yeast, stirring well together.

After skimming, take a handful of flour and a handful of salt, warm them by the fire and sprinkle them over the top of the fermenting wort; give the whole a good stirring and immediately fill the barrels, which must be dry and warm.

The stillions or tubs under the barrels will receive the yeast as it runs over from them.*

Fill up the barrels every three hours for a day or two. In four or five days the ale will have cleared itself of the yeast.

It must then stand till the vinous fermentation is finished. This may be known by the yeast at the bunghole turning brown and full of holes. When this appearance is detected, the barrels should be tightly bunged. In three weeks table-beer, and in two or three months the ale will be fit for use, according to its strength.

* The old-lashioned system was to skim off the top barm, then fill the casks quite lull, and immediately bung and peg them close. Then a hole was bored with a tap-borer near the summit of the stave, at the same distance from the top as the lower taphole is from the bottom, for working through that upper hole, which is a clean and more effectual method than working it over the cask; for being thus closely confined it soon sets itself into a convulsive motion of working, and forces itself fine, provided the casks are filled up five or six times a day.