Why, 175 years ago, did the town of Plzen in what is now the Czech Republic birth a style – the pilsner – that would one day conquer the world?  Why is Dublin’s world-famous beer so black? Did Arthur Guinness simply have a penchant for dark ales? What’s so special about Burton-on-Trent that “Burtonisation” is an actual brewing practice? The answer to all of the above is: water!

The solution to water

By Mark James, Beer Hawk's homebrew buyer

Beer is a solution of chemical compounds in water and without this indispensable life-giving liquid a lot more than brewing would cease to be.

When we talk about the water of Dublin, Burton or Plze? in a brewing context however, we’re referring to the different profiles of dissolved minerals that make each location’s water unique.

You may be surprised how many scientific advances were born of man’s desire to brew better beer; the pH scale that we use to measure acidity or alkalinity was invented by a Danish chemist at the Carlsberg Laboratory in 1909. The best beer is made when the mash’s pH is in the 5.2 – 5.6 range (slightly acidic), but most water sources are slightly alkaline.
How then did brewers hit the pH sweet spot, particularly in days past when bottles of laboratory acids were not an option?

Happily nature provides a solution: malt is acidic, and the darker the roast, the more acidic the grain. In Dublin where the water has a high level of alkalinity, lots of dark malt brings the pH down to the ideal level and a classic dry stout is born.

At the other end of the spectrum, Plze?’s water is so soft and free of minerals that the lightest malts alone provide sufficient acidity to hit the desired mash pH. It was here therefore that on 5th October 1842, the Bavarian brewer Josef Groll presented a bottom-fermented beer with a paleness hitherto unseen, a ‘Pilsner’, and the rest as they say, is history.

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