A Practical Treatise on Brewing/Tun Rooms
REGULATORS FOR THE TUNS.
It is, no doubt, a very desirable object to have the means of regulating and keeping in check the temperatures of the worts during fermentation; but if for that purpose we employ chains of pipes fixed in the gyle-tuns, consisting of different metals joined with each other, it is liable to the same objections with regard to galvanic action as when such pipes are otherwise connected with the tuns, and will generally be found to be attended with effects nearly as injurious.
Moveable regulators are the best; they can be applied or removed at pleasure. In winter or cold weather, regulators are very seldom necessary, and may then be altogether withdrawn from the gyle-tuns, thus removing the possibility of any voltaic action from a mixture of metals. The regulators which we recommend are very simple, and may be made at a very trifling expense.
Pipes consisting of one metal only, and of three or four inches diameter, should be formed into a rectangular or circular vessel. This vessel must of course be water tight, and strong enough to resist any pressure which may occur. In one of the sides of this vessel two openings about one inch and a half or two inches in diameter, must be made about ten inches apart, and these fitted with screw-joints, to which flexible water-tight pipes may be attached, the one for admitting the cold water, the other for its discharge anywhere over the top of the square. This vessel, which in size must be proportioned to the gyle-tun, may be suspended from any beam above the gyle-tun, by means of a rope and pulley, so as to be let down into the worts, or withdrawn at pleasure. These will be found to answer the purpose intended as well as the most expensive instruments now in use, or perhaps even better. These regulators should only be allowed to descend a few inches into the body of the worts. We all know that liquids, generally speaking, as they cool, become specifically heavier, and thus the portions first cooled on the surface will sink down, while those which are warmer, and of course specifically lighter, will rise up to supply their place.
If worts be cooled down too rapidly in the fermenting back, the fermentation will be checked, and it is sometimes found difficult to restore its vigour. By the above method, the process of checking the temperature is carried on much more gradually and equally, and without any risk of checking the fermentation. The worts, also, are at the same time all kept in motion, from the rising of the warmer and sinking of the cooler parts, which is also advantageous and perhaps better than rousing. Regulators, when placed near the bottom of fermenting tuns, do very little more, for a long time, than cool the worts at their own level, and even then not equally, unless the whole be kept in a constant state of agitation by means of rousing. Regulators, however, should never be used, so as to cool down the worts during fermentation, but should be so adjusted as to permit a gradual increase of temperature.