The town of Burton is situated on the eastern side of the valley of the Trent, which, at this point, is about 1.5 miles wide, and has a direction approximately north and south. This valley is mainly excavated in what are known as the Upper Keuper Marls. These marls form the uppermost division of the New Red Sandstone series of rocks, and consist of bright red clays, somewhat sandy in parts, and containing thin seams of gypsum or sulphate of lime.the mineral from which plaster of Paris is made. The marls are only to a limited extent water-bearing, and are, as a rule, very impervious. They are overlaid m the river valley by 25 feet to 30 feet of coarse, sandy gravel, and in this travel held up by the impervious marl floor, lies the water, which was at one time the only source of supply for brewery purposes. The usual method of obtaining this water is to sink large wells through the gravel to the underlying marl floor; but in some eases the so-called Abyssinian tube-wells have been driven down, but with only partial success, since the fine sand which is mixed with the gravel often gives trouble by stopping up the small holes at the lower part of the tube. Of late years attempts have been made to obtain water from more deeply seated sources by driving deep bore holes into the marl beds. The water so obtained, although as a rule, not very copious in quantity, is of exceptional purity. Thus, we see there are two sources of the brewing water of Burton; one the gravel beds overlying the marl, and the other the red marl itself, the water from the latter source being obtained by deep borings. In both cases the water is very hard, and is highly charged with gypsum, which gives it the peculiar properties and makes it so highly prized for brewing.
The deep-seated waters are, however, much more highly charged with this mineral than those derived from the shallower wells. So much so is this the case, that it is sometimes found expedient to mix the more highly mineralized water with the ordinary well waters.
The following analyses give a fair idea of the composition of the two waters:—
No. I. is from an artesian boring in the red marl.
No. II. is from a well in the valley gravel.
Grains per gallon. Grains per gallon. Sulphate of Lime 70.994 25.48 Carbonate of Lime 9.046 18.06 Carbonate of Magnesia 5.88 9.10 Sulphate of Magnesia 12.60 - Sulphate of Soda 13.30 7.63 Chloride of Sodium 9.170 10.01 Chloride of Potassium 0.966 2.275 Carbonate of Iron 1.218 0.90 Silica 1.12 0.84 Total solid residue 124.294 74.293
"Noted Breweries of Great Britain and Ireland, vol. 1" by Alfred Barnard, 1889 pages 416 - 418.
I was struck by the difference between the water from the two wells. Complicated isn't it? Two wells for brewing water, two wells for cooling and other wells for cleaning water. The ground around Burton must have been like Swiss cheese from all the brewery's wells.
It's the first mention I've seen of the need to blend the mineral-rich water to tone it down. Hard? Well you wouldn't want to meet it down an alleyway after throwing out time.