Casey's Beer

Water is the main ingredient of beer. Water quality is therefore of vital importance. Perhaps contrary to our intuition, rain and distilled water make quite poor brewing water. The water from most of the traditional brewing centres is usually hard. The main exception is Pilsen and its very soft water.

Traditional beer styles have developed in particular geographic areas. Through a long process of trial and error these styles evolved to make best use of the available water. Whether the water was drawn from lakes, rivers or wells, the surrounding country and its geology stamped its character on the water that flowed through it.

The mineral content of water is important for brewing for two reasons. Firstly, hard and soft water taste different, consequently this has an impact on beer flavour. Some beers have a pronounced minerally, even stoney flavour. Some British ales, such as Old Speckled Hen, are a good example of this.

Secondly, the chemical reactions which occur during mashing and other brewing processes are sensitive to pH, that is the degree of acidity or alkalinity. Mineral salts determine the pH of the water containing them. They also determine how easy or not it is to change the pH, buffering. As well, calcium is an important for mash reactions.

Brewers have long realised that different waters suited some beers rather than others, or that some waters were completely unsuitable for brewing. They also did what they could to improve or modify their brewing water by such measures as boiling or adding slaked lime to very hard water to precipitate excess mineral salts, or by adding mineral salts to soft water. It was not until the early nineteenth century that water chemistry began to be properly understood. The big push for this came from explosive popularity of pale beers that started first in Britain with the Burton pale ales, and then in Europe with the pale lagers from Bohemia, Pilsener beers.

As this table shows, the traditional brewing centres have waters of very different characters.
Pilsen Dortmund Munich Burton London Dublin
Calcium 7 225 75 275 90 120
Magnesium 2 40 18 40 5 5
Sodium 2 60 2 25 15 12
Sulphate 5 120 10 450 40 55
Carbonate 15 180 150 260 125 125
Chloride 5 60 2 35 20 20

Total hardness 30 750 250 875 275 300

Measurements are in parts per million.

An example of what this meant in practice is porter. Porter was the great beer of the British Isles for nearly two centuries, and London was the centre of porter brewing. Breweries outside of London tried to brew porter but with very mixed success. London was the porter capital because carbonates dominate the character of its water. Carbonates make the water quite alkaline, and the acidity of the dark malts used in porter balanced the alkalinity of the water. The other great centre for porter is of course Dublin and the porter of Arthur Guiness’s company – Dublin water is strongly carbonate. When porter was brewed in areas without carbonate water, the mash was too acidic.

You might also notice that Munich water has a strong carbonate character – the traditional beer of Munich was a dark style, the dunkel. Pale beers have only been brewed in Munich since the late 1920s, well after water chemistry was mastered.

About the only water to be thoroughly unsuitable for brewing is that with a strong sodium character.

Whatever the mineral character of the water, it needs to be free from organic material, bacteria, pesticides and herbicides. In some parts of the brewing world old and well established breweries may have their own water sources such as wells or springs. In most cases breweries now draw on municipal water supplies.

Nonetheless, municipal water supplies still have the character of the surrounding country. Depending on the quality of municipal water, breweries will often filter it to remove any disinfectant chemicals such as chlorine. The water may also be disinfected using ozone or ultra-violet light.Depending on the mineral character of the water, breweries may also use reverse osmosis to remedy excess ion content. They may then add back mineral salts to give the water desired character for the beer to be brewed.

Generally the best type of water for brewing is soft water uncontaminated by organic material or industrial residues. Pilsener beers require soft water, and for beer styles that need harder water mineral salts are easily added.