"The tintorial value of a black malt will, as a rule, lie between 1000 and 1500° expressed on a 10-per-cent. solution of the malt, read in a 1-inch cell, using 52° series of glasses in a Lovibond tintometer. Any result under 1000° must be regarded as low, and in purchasing black malt it would be quite reasonable to name this figure as a minimum. I have occasionally met with black malts giving so low a tintorial value as 600°. With such malt it is quite obvious that for colouring purposes double the usual quantity of malt would have to be employed, a matter which would involve considerable expense."Some handy numbers for reference there. I wonder how that compares with modern black malt?
"Journal of the Institute of Brewers vol. 13, 1907", page 488.
"As the price of black beer grains is less than of those from pale malt,—the difference being 6d. a quarter in London, but considerably greater in some districts,—many brewers mash their black malts by themselves or mixed with about an equal weight of pale malt, a special small mash-tun being devoted to this purpose. This practice has the advantage of enabling the bulk of the grains to be sold as pale, realising therefore the maximum price, the black grains themselves then selling at about two-thirds of the ordinary price. There is a good deal of difference of opinion on the advantage of this practice. Some brewers, whose views are to be respected, insist that there is a loss of flavour unless the black malt is actually mashed with the bulk of the grist. Others maintain that there is no such advantage, and that only a depreciation in the selling price of the grains results. The practice of adding a portion of the black malt to the copper (in that case generally specially finely ground) is quite common. Indeed, there are breweries where the whole is added at that stage, though this, I think, only occurs where caramel is also used. There is certainly a considerable roughness of flavour, amounting almost to bitterness, resulting from the use of any large quantity of black malt in the copper. Though this may in some cases be no objection,—indeed, I know of one or two where it is actually an advantage,—it is in others quite the reverse. The fact is that in this matter much depends upon the particular character of the stout required for a district. In some districts a dry flavour is desired, in others the maximum of softness, and it is in the production of this beer almost more than any other that the brewer has to study the idiosyncrasies of his local trade."
"Journal of the Institute of Brewers vol. 13, 1907", pages 488-489.
The price being talked about in the first couple of sentences could easily cause confusion. They're talking about the price brewers get for their spent grains. In general, London brewers mashed all their grains together. Barclay Perkins often threw a bushel or two of black malt into the copper.
Most interesting in this paragraph is the mention of differing regional tastes in Stout. And that these were greater than for other types of beer.
"There is some difference in the extract which is yielded by black malt when mashed by itself or when mashed with malt. This is naturally the case, since black malt is almost invariably non-diastasic, yet there may remain a proportion of practically unaltered starch which would not enter into solution when extracted by itself. A series of samples gave an average extract of 72.5 lb. per 336 lb. when extracted with water alone, as against 77 lb. when extracted in conjunction with malt.
The extracts above given are those yielded by 336 lb. of black malt, but this material is generally sold by bulk, rarely by weight. The actual weight per quarter of black malt varies more than probably most brewers suspect, unless they have taken the trouble to weigh their deliveries. I have seen weights recorded as low as 215 lb., and as high as 290 lb. There may thus be very wide discrepancies in the actual weight of material which the brewer purchases, yet the proportion of black malt, being as a rule so small, brewers have hitherto paid little attention to the matter. On the basis of an average weight of 270 lb., black malt gives a laboratory extract of about 60 lb., but in the brewery this figure could hardly be expected to be realised ; an extract value of 50 lb. a quarter is probably a more correct allowance."
"Journal of the Institute of Brewers vol. 13, 1907", pages 489-490.
I'd already noticed that the weight of a quarter of black malt could vary considerably. The weights I've seen have generally been a bit lower than the 270 lbs the author gives as an average. Annoyingly, this doesn't answer an important question: were brewers using volume quarters in their records? The extract of 77 brewers pounds (for a 336 pound quarter) seems quite high to me. I'm sure most brewers weren't that fussed about the extract from the black malt as it made up such a small percentage of the grist.
There's still loads more of this to come.