Despite what many homebrewers believe, party-gyling (or is that parti-gyling? not quite sure of the correct modern spelling) is not using each separate running to make a different beer. That method of brewing disappeared about 1762.
And, despite what many beer writers have claimed, party-gyling didn't pretty much die out by 1800. It's a common feature of all the brewing records I've looked at from 1805 to 1965. That's real party-gyling. Where you blend 3 or 4 worts of different strengths in differing proportion to create several beers. The important point is that even the weakest beer will get some of the strongest wort. For reasons which Lloyd Hind will soon explain.
Brews divided in the fermenting vessels to make worts of different gravities are known as parti-gyles. That described in the previous Section could, for example, be divided among other ways to produce:
100 barrels at 1050 = 5,000 degrees
100 barrels at 1040 = 4,000 degrees
200 barrels at 1032 = 6,400 degrees
The extra length can be obtained by adding more liquor to the coppers or by boiling the necessary length of trated liquor and passing it over the refrigerators to add to the wort in the fermenting vessels. It is possible to produce many parti-gyles from one copper length by adjusting the gravity of the weaker wort with liquor in the fermenting vessels. It is, however, more usual to collect more than one copper at different gtravities, and blend them in the fermenting vessels. The second and third coppers must then be of considerably lower gravity than the first. If the worts were divided in the coppers as they ran from the mash tun, they would necessarily be of abnormal composition, with proteins, salts, etc. very unequally divided. As a result, the break in the last copper might be defective, the fermentation of the weaker worts likely to suffer and the flavour of the beer not as good as it should be. A boiling fermentaion frequently occurs in a weak wort made in a parti-gyle with a strong one. It is consequently advisable to hold back some of the stronger mash tun worts for the later coppers, even though it may be inconvenient to equalise their gravities.
187 barrels at 1045.7 = 8,546 degrees
192 barrels at 1037.25 = 7,152 degrees
The hops are divided between the coppers in proportion with the extracts, say 245 and 203 lb. The worts collected in the fermenting vessels might be expected to be as follows, with 25 barrels of hop sparge and 80 barrels of liquor, taken at a specific gravity of 1004,
146 barrels 1st copper wort at 1056 = 8,176 degrees
149 barrels 2nd copper wort at 1046 = 6,854 degrees
105 barrels hop sparge and liquor at 1004 = 420 degrees
It is difficult to work out the proportions of the two worts and liquor to make the three lengths and gravities required, since the gravity of the first copper only is known when the proportions in which it must be divided have to be decided. A first approximation can be found by the following simple method.
The differences between the gravities of the first copper wort, second copper wort and sparge, and the required gravity, taken in reverse order, give the proportions in wjhich the two worts and sparge must be mixed to give that gravity. Thus to obtain 1050 from a first wort of 1056, with second wort and sparge estimated at 1046 and 1004, the proportions are: 1st wort 46, 2nd wort 4, sparge 6. The respective lengths to make 100 barrels at 1050 would be 83.1, 7.1 and 10.8 barrels. This device cannot be used for the 1050, 1040 anmd 1032 worts simulataneously, since it takes no account of the available copper lengths.
The following figures are obtained by adopting it for the two stronger worts and assigning the surplus copper and sparge lengths to the 1032 wort.
1050 1040 1032 1st copper 82*56 = 4,592 62*56 = 3,472 2*56 = 112 2nd copper 8*46 = 368 10*46 = 460 131*46 = 6,026 sparge & liquor 10*4 = 40 29*4 = 116 66*4 = 264 100 5,000 101 4,048 200 6,402 100 barrels at 1050 101 barrels at 1040.1 200 barrels at 1032
It is obvious that the composition of the 1032 wort leaves much to be desired, on account of the excess of second ciopper wort. It is, indeed, essential to scrutinise all calculated blends in this way, since it many of the possible variations may be unsatisfactory. A reasonably proportioned bkend in one of the gravities may be accepted or fixed. The other two would be suitably adjusted. In this case, the 1050 wort is taken as the starting point.
The other two are adjusted by reducing the 1st copper length in the 1040 wort and iincreasing that in the 1032, with corresponding alterations in the sparge lengths to produce the required gravities, giving the following figures,
1050 1040 1032 1st copper 82*56 = 4,592 30*56 = 1,680 34*56 = 1,904 2nd copper 8*46 = 368 50*46 = 2,300 91*46 = 4,186 sparge & liquor 10*4 = 40 21*4 = 84 74*4 = 296 100 5,000 101 4,064 199 6,386 100 barrels at 1050 101 barrels at 1040.2 199 barrels at 1032
"Brewing Science and Practice" by H. Lloyd Hind, 1943, pages 738-741.
In the example Lloyd Hind gives, there are worts of 1056, 1046 and 1004 and the target gravity is 1050. So starting with the sparge wort, the difference between thaat and the target gravity is 1050 - 1004 = 46. For the 2nd wort it's 1050 - 1046 = 4. For the first wort 1056 - 1050 = 6. Giving the proportions of 46 1st wort: 4 2nd wort: 6 sparge.
Simple, isn't it? I'll provide some real-world examples tomorrow.