I'm still trying to get back into research mode after many weeks of mostly travelling. Which is why I'm continuing to regurgitate material from my mega-manuscript "Beer, Ale and Malt lliquor". With today something about mid-19th century mashing.
During the mashing process, starch is converted to dextrine and then into sugar (maltose). By controlling the temperature and mashing time it was possible to control the proportion of dextrine and sugar (maltose) in the wort. How much dextrine was desirable, depended on the type of beer being brewed. Beers with a full palate, such as Stouts, and beers intended to be aged or exported, larger amounts of dextrine were beneficial. Dextrine would not only add richness to the finished beer, but help to slow fermentation, something essential in a beer that would not be sold immediately. In beers intended to be fermented and sold quickly, relatively small amounts of dextrine were needed. (Source: "The Art of Brewing" by Faulkner, 1876, page 63.)
Worts with large amounts of detrine did not clear as easily nor ferment as readily. (Source: "The Art of Brewing" by Frank Faulkner, 1876, page 66.)
Faulkner made specific mention of the difficulties of getting Stout right: "Much difficulty is experienced by many brewers in obtaining full tasted stouts, the error in the generality of processes being the excessive employment of saccharines; beyond this, the brown malt of a porter grist, besides having a different latent heat, has had its original starch so modified by the torrefication that it has undergone, that if ordinary heats are employed you are certain to procure from it a large proportion of actual sugar; and thus, from one cause or another, your stouts are highly saccharine and yet very deficient in palate fulness." (Source: "The Art of Brewing" by Frank Faulkner, 1876, pages 71-72.)
To get the required proportions of sugar (maltose) and dextrine, good quality malt, the right type of water and careful control of the mashing temperature were essential. (Source: "The Art of Brewing" by Frank Faulkner, 1876, page 64.) Starch was converted into dextrine at one temperature and when the heat was increased dextrine was converted into sugar. By starting the mash at one temperature and then increasing it and leaving it to stand for a specific length of time, the conversion of dextrine into sugar could be controlled. (Source: "The Art of Brewing" by Frank Faulkner, 1876, page 65.) "You first of all use such a degree of heat as is capable of dissolving disatase, enabling it to convert starch into dextrine; and then you, by a simple addition of a further quantity of liquor at an increased temperature, enable the diastase to induce a further change - the conversion of dextrine into sugar." (Source: "The Art of Brewing" by Frank Faulkner, 1876, page 65.) Presumably this is why part of the way through the mash water hotter than that initially used was introduced via the underlet. This technique can be found in the logs of Whitbread and Fullers.
According to Faulkner, darker malts such as black and brown cooled mashing water less than paler malts and the same initial temperature could be obtained with a lower striking heat. (Source: "The Art of Brewing" by Frank Faulkner, 1876, pages 67-68.) A thicker mash required a higher striking heat (pretty obvious, as there was less water to heat the malt) and gave a less clear wort. A thin mash produced a clearer wort, but a worse extract. (Source: "The Art of Brewing" by Frank Faulkner, 1876, page 68.)
This was Faulkner's preferred method of mashing when using an external Steel's masher: "I am in favour of using two barrels of liquor per quarter when through a mixing machine at about 168º, which gives me an initial temperature of of 150º, rising to 156º or 158º before setting tap, and a tap gravity of 33º per barrel [og 1090º]. Now such a mash gives you, I believe, dextrine and sugar in equal proportions, with a satisfactory malt. If the malt is imperfectly malted, your dextrine is in greater proportion, since the diastase has had more work to effect, and you must adopt either some special kind of fermentation to allow of this dextrine being decomposed, or you may keep your wort for some time at a temperature of 170º after it runs from the mash tun, to allow of the diastase exerting its converting power on the excess of dextrine before the power of this converting agent is destroyed by the boiling temperature in the copper, or you may increase the proportion of sugar in your worts by the addition of saccharine." (Source: "The Art of Brewing" by Frank Faulkner, 1876, page 68.)
As we'll see in the next chapter, "dextrine and sugar in equal proportions" is a bit wide of the mark. The ratio of maltose to dextrin was at best 3:1.
Faulkner's recommendation was somewhat different for breweries equipped with an internal rake masher: "With rake machinery you mash in with about one and a-half-barrels per quarter at some 162º, and you allow this mixture to stand some thre-quarters of an hour; and then a secondary quantity of liquor, at a much higher temperature than the first, is forced under the false bottom and mixed in by the machinery. . . . If a dextrine beer is required - and I had better remark that it never is wanted in a small brewery - you take a sufficient quantity of second flow liquor at a rate of half a barrel per quarter to bring up the heat of the mash to 156º or 158º, while you stand some hour and a quarter after final mixing is finished, and then, on setting tap, bring the wort to the boil as soon as possible, to destroy the converting agent, and prevent the proportion of constituents being altered. . . .If, on the other hand, a saccharine beer is wanted, your second flow of liquor is taken at such a heat that the intial temperature is raised to 165º or 170º . . . . Time is another important feature. The longer you allow the mash to stand at this elevated temperature the more sugar you will obtain; but you must, on no account, stand so long as to allow cooling down taking place." (Source: "The Art of Brewing" by Frank Faulkner, 1876, pages 69-70.)
With the "saccharine beer" method, it was important to ensure all the starch had been converted before applying the higher temperature water, otherwise starch might end up in the wort. Iodine was used to test the wort for starch as it was run off. If it were present, the wort was kept at 170º for an hour in the copper before being boiled. (Source: "The Art of Brewing" by Frank Faulkner, 1876, page 71.)
Faulkner recommended sparging in the same way, no matter which type of mash had been employed. The sparging water needed to be warm enough to convert any remaining dextrine in the cooler upper portion of the mash to maltose, but not so hot as to dissolve unconverted starch nor destroy the diastase. If the temperature fell too low, lactic acid was likely to form. To satisfy all these considerations, 176º F was the perfect temperature. (Source: "The Art of Brewing" by Frank Faulkner, 1876, pages 73-74.)
Now wasn't that fun? No, I suppose it wasn't. It does free up Saturday for me. Which is what really matters.
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