Thursday, 5 April 2018

The Salts of Brewing Waters

If you follow me on Twitter, you might find some of the following familiar. I posted an image of the table without explanation a few days ago.

I love analyses of brewing waters. Especially when I come across ones I've never seen analysed before. As is the case here with Leeds. Never seen anything about Leeds water before.

The article divides brewing waters into three classes:

A. Burton-like water full of gypsum
B. Chalk waters without gypsum.
C. London-like water with lots of carbonates and sulphates.


BREWING waters, which are chiefly derived from wells or borings, are on a somewhat different footing from potable waters, for, in the latter, purity is the desideratum, and if, in addition, poisonous metals are absent and the solid matter not excessive, the water may be considered as satisfactory. In the former, however, besides purity, a knowledge of the dissolved salts is almost, if not absolutely, essential. It is unnecessary for me to remind you of the great influence of geological construction upon the character of the beers brewed in any district, the gypsumous waters of Burton, long famous for pale ales, and the soft, stout-producing waters of Dublin and London, being typical examples. We shall find it simplify matters to divide waters roughly into three classes—(a) Gypseous waters (that is, rich in calcium sulphate), such as are found at Burton. (b) Waters containing little or no gypsum: to this class belong those derived from the chalk, and those poor in dissolved salts, like the Leeds town supply. (c) Waters containing no gypsum, but carbonates and sulphates of the alkalis. Such are derived from below the London clay, and are admirably adapted for producing black beers.

The accompanying tables give two typical examples of each class. The figures represent grains per gallon :—

(1) An artesian boring ; (2) Burton deep well; (3) Deep well in the chalk; (4) Leeds supply; (5) Very deep boring; (6) Also a boring.

We will assume that a water analysis has been made, and yielded a quantitative knowledge of the bases and acids present, which you will admit can be obtained with every pretension to accuracy. A list of these bodies doubtless appears very interesting, and, if imposingly drawn up, might possibly: inspire respect, but it has one fatal disadvantage, which is its  almost, if not complete, uselessness in the hands of the manufacturer. A chemist might form some idea as to the constitution of the salts present, but the information deduced would be limited if one had to criticise the water as to its value for brewing purposes. The reason is not far to seek, for though a glance tells us, for example, that the dissolved salts are rich in lime and sulphuric acid, it does not follow that all the lime or all the acid exists in solution as calcium sulphate, for there may be other salts of lime and also sulphates of other bases present. It has hence become necessary to have as accurate an idea as possible of the salts present, and since these cannot be directly estimated, the acid and basic bodies are combined in the most probable manner, and I may say that the data thus obtained are of great value. In setting about this combination, the following facts are taken advantage of :—(1) The affinity of potassium for chlorine is greater than sodium, hence chlorine is combined with potassium before sodium; (2) Calcium nitrate is decomposed by potassium carbonate, sulphate, and chloride, the sodium salts probably acting in the same way. The alkalis are therefore given the preference over lime for nitric acid; (3) Magnesium sulphate is decomposed by calcium chloride, and consequently it seems natural to unite sulphuric acid with lime rather than with magnesia.

1 2 3 4 5 6
Silica 0.24 0.49 1.1 0.07 0.28 0.7
Alumina 0.18 0.49 0.04 0.07 0.61 0.43
Lime 16.34 36.33 17.37 2.01 9.92 13.46
Magnesia 2.09 10.15 0.49 0.52 3.24 4.6
Soda 5.89 7.25 1.72 0.77 21.07 10.7
Potash - 0.86 - - - Trace
Chlorine 7.98 2.37 1.99 0.8 6.08 3.64
Sulphuric acid (SO3) 19.86 52.29 5.14 1.36 12.42 14.31
Nitric acid (N2O5) - 1.25 3.51 0.13 0.16 0.16
Sodium chloride 11.13 3.9 3.28 1.32 10.02 5.99
Sodium nitrate - 1.97 - 0.19 0.25 0.25
Sodium sulphate - 10.21 - - 22.04 17.01
Sodium carbonate - - - - 9.59 -
Calcium chloride 1.9 - - - - -
Calcium nitrate - - 5.33 - - -
Calcium sulphate 33.76 77.87 8.74 2.31 - 8.02
Calcium carbonate 2.64 7.62 21.34 1.69 17.54 18
Magnesium carbonate 4.39 21.31 1.03 1.09 6.8 9.66
Silica, iron, and alumina 0.41 0.98 1.14 0.14 0.89 1.13
54.23 125.45 40.86 6.74 67.13 108.6

* A paper read before a meeting of the Yorkshire section of the Society of Chemical Industry."
The Brewers' Guardian 1893, page 94.
You can see that the Leeds water has an extremely low mineral content. I really wish I knew what Tetley's water treatment was. Undfortunately, it isn't mentioned in their brewing records.

1 comment:

Phil said...

Wasn't that the title of a four-part 'suite' on side two of Greenslade's third album?