SECTION XI.
Of the Proportion of cold Water to be added to that which is on the point of Boiling, in Order to obtain the desired heat in the Extract.
Thedegree of heat, which causes water to boil is determined, by Farenheit’s scale, to 212. It is in our power to give to any part of the extracting water this degree of heat; and by adding to it a sufficient proportion of water of an equal heat with that of the air, and blending these two quantities with the grist, to bring the whole to the required temperature. The rules for obtaining this end are extremely simple, and cannot be unknown to those, who are skilled in arithmetical operations. But as our view is to render this part of our work generally useful, we think it will be proper briefly to lay down these rules, and to illustrate them by the examples of our two brewings.
Rule to ascertain the heat of the first Mash.
Letaexpress the degree of boiling water,bthe actual heat of the air,cthe required degree for the extract,mthe whole quantity of water to be used,nthe volume of the malt;x, that part of the water, which is to be made to boil, will be determined by the following equation.
The quantity of water used, added (+) to the volume of the grist.
Their sum (z) multiplied (×) by the heat required, less (-) the heat of the air.
This produce divided (÷) by the heat of boiling water (212) less (-) the heat of the air will quote how much is to be made to boil or brought through (212) that is how high the copper is to be charged, the remainder of the length of the whole liquor for this mash, is the quantity to be cooled in.
The first example is that of a brewing of small beer, when the heat of the air is at 60, (see page 232.) The volume of the 6 quarters of malt was estimated at 3,42 barrels, (see page 268;) the first liquor is 14½ barrels, (see page 247) and the heat required for the first mash 154 degrees, (see page 247.)
First Mash.
The next example of a brewing is that of a grist of eleven quarters of malt for porter or brown beer; the medium heat of the air is forty degrees, the volume of the grist, 6,32 barrels, (see page 268) the first liquor to mash with sixteen barrels, (see page 245) and the heatexpected in the mash, one hundred and fifty-seven and a half29degrees. (See page 245).
First Mash of brown strong beer.
I will give one proof of the certainty of this rule, by setting down the state of this first mash from it.
So long as the mixture consists only of two quantities of different heat, as is always the case of the first mash, the preceding solution takes place. But in the second and other mashes, where three bodies are concerned, each of different heat, viz. the boiling water, the cold water, and the mash, are to be mixed, and brought to a determinate degree, the rule must be different; yet, like the former, it is the same with what is used in similar cases of allaying, when different metals are to be melted down into a compound of a certain standard, or different ingredients of different value to be blended, in order to make a mixture of a determinate price. What the different density of the metals, or the different value of the ingredients are, in these cases, the different degrees of heat of the boiling water, the grist, and the air, are in this.
Rule to ascertain the heat of the second mash, and of the subsequent ones.
Let the same letters stand for the things they signified before, anddexpress the actual heat of the grist, then will
or in plain terms, the heat required less (-) the heat of the air, multiplied (×) by the quantity of water used.
The heat required less (-) the heat of the goods, multiplied (×) by the volume of the goods.
Their sum (z) divided (÷) by the heat of boiling water, (212) less (-) the heat of the air.
Will quote the quantity to be made to boil, or to be brought through (212) the remainder part of the whole liquor for the mash is consequently the quantity to be cooled in.
We may now collect the circumstances of the two brewings, and find the quantity of boiling water, required for their second and subsequent mashes, exclusively of the incidents which will hereafter be mentioned.
The first mash for the six quarters of small beer, had 154 degrees of heat, but this and every mash loses, in the time the extract is parting from it, 4 degrees, which reduces the heat to 150 degrees. The volume of this grist, in its dry state, was 3,42 barrels, but now, by being expanded, and having imbibed much water, it occupies three times that space, or 10,26 barrels; the air is supposed to continue in the same state of 60 degrees of heat. The length and heat to be given to the three remaining mashes, are as follows. (See page 247.)
Second Mash for Small Beer.
Third Mash.
Fourth Mash.
The liquors of this brewing of common small beer, when the mean heat of the air is 60 degrees, must therefore be ordered in the following manner (the incidents hereafter to be noticed, excepted.)
The heat of the first mash for the 11 quarters of brown beer, was 157 degrees, (see page 245) and after the parting of the extract from it, 153; the volume of the grist, in its dry state, was valued at 6,32 barrels of water, (see page 268) but, for the reasons before mentioned, it now occupies three times that space, or 18,96 barrels. The air is supposed to continue at 40 degrees, and the length and heat to be given to the different mashes, were determined as follows: (see page 245.)
Second Mash of Porter, or brown strong.
Third Mash.
Fourth Mash.
Fifth Mash.
The liquors of this brewing of brown beer must therefore be ordered in the following manner:
What in the brewery is generally called cooling in, must be settled for this brewing according to the number of barrels of cold water specified as above, the incidents hereafter to be noticed excepted.
Each of these calculations may be proved in the same manner as was done before. This method of discovering the proportion of water to be cooled in, deserves, on account of its plainness and utility, to be preferred to any other, which depend only upon the uncertain determination of our senses.