Today's text will be perfect for any of you who fancy adopting party-gyling. It tells you how to calculate the blends of wort.
"I claim for this work that it is entirely practical, and I therefore give an actual example of a brewing calculated out from first to last; and, in order to render it of the greater service, I purposely take a party gyle, and will say that it is a brewing in which sugar forms a considerable portion of entire extract. We are brewing as follows : Equal lengths of a 22, 20, and 18 lbs. beer, 110 barrels of each, the sugar proportion to be one-fifth, the saccharine in use yielding 86 lbs. per cwt., the malt being reckoned at 87.0 per qr., the wort to be boiled off in two lengths in four separate coppers of varying size. The figures below will, I think, explain themselves, at any rate, with the aid of the few side remarks appended:—
EXAMPLE OF BREWING ESTIMATE, COPPER, AND SUB-DIVISION OF WORT CALCULATIONS.
110 barrels, at 22.0 = 2420
110 barrels, at 20.0 = 2200
110 barrels, at 18.0 = 1980 1320/36 sugar extract = 37 cwts.
Saccharine proportion 1/5)6600(
Malt extract, at 87 per qr.)5280(60 qrs. 4 bush.
That is, we mash 60 qrs. 4 bush, malt, and dissolve 37 cwts. of sugar to produce quantity required.
The next step is to ascertain copper lengths, in order to obtain 880 nett barrels in collecting vessels.
Barrels in collecting squares 330
Evaporation by boiling off 4 distinct lengths—
12 + 12 + 10 + 12 = 46
Hop retention and bulk contraction—
14 + 24 = 38
This length we distribute as follows :—
No. I. Copper, 125 First wort.
II. „ 125 }
III. ,, 72 }-Blend as second wort.
IV. „ 92 }
On the coppers being charged, gravities were found as under, and it is as well to remark that the strong runnings had been more or less divided over entire length:—
First wort, 125 barrels at 32.0 gravity.
Second wort, 125 ,, at 15.3}
„ „ 72 „ at 8.5}- Or, 289 at ll.l.
„ „ 92 „ at 7.2}
By referring to losses, we see that the first wort evaporates 12 barrels, and diminishes in bulk 14 by hop retention, contraction in bulk, and cooler evaporation. The second blended lengths lose 84 barrels by boiling, and 24 by hop retention, &c, so the nett gathering quantities would be 99 first wort, 281 second wort, making up the 880 barrels required ; while at the same time the gravities would increase as under. First wort, 2.5 per barrel; second wort, 1.7 per barrel. At making up of coppers our calculation stands thus—
First wort ... 99 barrels at 34.5 = 3415
Second wort . . 231 ,, at 12.8 = 2956
Total First First
length Vessel length
330 : 50 :: 99 = 15 barrels
that is, 15 barrels of the first wort would be placed in the fifty-barrel collecting vessel, the proportion for the other vessels being ascertained in the same way. Now, in the case of a "party gyle" a combination of beers of unequal gravities, the varying "strength" is arrived at, of course, by the unequal intermixture of the several worts, and the problem to be solved is what this unequal mixture must be, In the case above we know that we have sufficient wort and extract to give required gravity and length of each beer calculated for. How, then, are we to subdivide 99 barrels at 34.5, and 281 at 12.8 to give in collecting vessels 110 at 22.0, and similar quantities at 20 and 18 ?
The simplest plan is to deal with each beer separately, seeing what excess of extract we shall have if taking all first wort to such beer, and then ascertaining how any excess can be displaced by substituting second wort for first. Thus in the example above it is apparent that by substituting second wort for first, for every barrel of second wort used we displace 21.6 lbs., the difference between 12.8 and 34.5.
The other beers are calculated for in the same manner, and it will be seen that the results come out with perfect accuracy. The rule for division of worts in party gyles may be thus expressed. Multiply each length by gravity of first wort; deduct from result the lbs. extract required, and divide excess by difference between gravity of first and second worts ; the quotient will be the barrels of second wort required, which, subtracted from total, gives barrels of first wort.
It will be perfectly evident that the two calculations I have last given suffice for many purposes in the brewery, such as the proportional distribution of certain bulks into vessels of dissimilar size, the blending of different lengths of a single beer existing at varying final attenuation into separate racking tanks, so that a mean gravity is attained, and also constitute a means of readily calculating the proportional intermixture of two or more beers at dissimilar original gravity, to produce a beer of any mean strength required."
"The theory and practice of modern brewing" by Frank Faulkner, 1888, pages 74 - 77
Something has surprised me since I started tis little examination of party-gyling. How little there is about it in the technical literature. Really bugger all. Quite a shock given how prevalent the technique was.