Water for Brewing

From the Journal of the Institute of Brewing – 1922

WATER FOR BREWING.

The question of water in brewing is of perennial interest to brewers, and in a series of editorials in Les Annales de la Brasserie et de la Distillerie, our distinguished foreign member, Professor A. Fernbach, discusses the properties of different liquors, and generally reviews the progress of our knowledge of this subject.

It is somewhat remarkable that, despite the obvious importance of the subject, treatises on brewing of comparatively recent dates practically ignore the question; indeed, it is only within the last 30 or 40 years that any systematic work has been carried out.  The first indication that we have of any research is in Lintner’s work, where analyses of the liquors used in various breweries in Munich and elsewhere are given.  Prior to this, the general opinion seemed to be that any water was suitable for brewing, provided that it was good drinking water.  Many years ago attention was directed to the fundamental differences between waters from different sources, and investigators showed that the dissolved substances in the waters exercised a profound effect on the character of the beers produced from them; in particular, he studied the effect of the presence of calcium sulphate.  In this earlier work, however, the investigations were of a superficial character only, the observations recorded being the effect of the dissolved salts on the colour of the resultant worts.  It became known that a hard water was most suitable for pale ale brewing, while stouts required a soft water.

The question of the colour of a beer is, after all, a secondary matter, of small importance in comparison with its other properties—taste and stability, etc.—all of which are largely dependent on the character of the brewing liquor.

Brewing is an operation the success or failure of which depends almost entirely on the correct functioning of certain complex substances, known as enzymes, which are highly susceptible to minute variations in the conditions under which it is carried out; in particular, they are extremely sensitive to variations in the medium in which they act, and it is from this point of view that most modern work on brewery liquors is carried out.

The mineral matters in water are derived from the various layers of soil through which it has percolated, and consist of various salts, of which those of calcium and magnesium are the most important.  As is well known, calcium exists in two different forms in water—as carbonate, or more correctly, bicarbonate, and as sulphate—which are responsible for the temporary and permanent hardness of the water respectively.

The essential effect of these calcium salts contained in water is to modify the reaction of the resultant worts, by suppressing or augment ing the natural acidity of the malt.  This modification has a marked influence on the various enzyme actions, and, as a consequence, is a determining factor of the quality of the resultant beers.  Thus a water, rich in carbonates, will tend to decrease the acidity of the worts and so inhibit saccharification, and consequently will give a beer which is rich in the more complex starch degradation products—maltodextrins—and therefore does not attenuate strongly.  Hence the use of such waters in the brewing of heavy beers, such as stouts and porter.  On the other hand, a gypseous water is best suited for light ales which are required to be fermented to the limit of attenuation.

Further, the effect of the reaction of the medium influences the activity of the proteolytic enzymes in almost exactly the same manner as it affects the amylolytic.  The nitrogenous constituents of a wort play a most important part in the functioning of the yeast.  If they are highly complex—as albumoses and peptones— the yeast will not be so active as if they had been further degraded to amino acids.  This, in itself, results in a lowering of the attenuation, and affects the character of the beer.

All the difficulties which may arise are emphasised when large quantities of raw grain, or other adjuncts, are used. It is then of paramount importance that the enzymes of the malt shall act under optimum conditions, and the necessity for carefully regulating the pH value of the worts cannot be overestimated.

From the foregoing, it will be readily appreciated that an accurate knowledge of the conditions necessary to secure a given result is essential if brewing is to be adequately controlled, and a consideration of the fundamental effects of the constitution of the brewing liquor serves but to accentuate the importance of this phase of the question.