Water: Nothing is a more fundamental and obvious beer ingredient than water. At up to 97% of the total, water simply is the largest percentage of any beer. It accounts for much of the flavor and perceptions of any beer when it is finished. Entire styles are accountable to the profile of water, from the hardest with Burton-On-Trent for hoppy pale ales to the roundness and malty character of Bohemian Pilsner from the almost snow melt sources in Pilzen.
It is a safe bet that the water source for a brewery can make or break any effort at quality. A now defunct major brewer used to claim, “It’s the Water….” So why is it so important and yet so casually thought of by most home brewers? Simply, it is easily available and just seems to do its job of making barley and hops turn into beer.
There are several reasons to think of your water source when creating a recipe. First, water must be clean from biological, physical and chemical contamination in order to be suitable for brewing. Second the mineral content is going to have an effect on pH, enzyme activity, hop perception and clarity of finished beer.
Direct well, river or lake sources can have wild variation in suitability for brewing. At any time of year, the mineral content of both brewing friendly and beer shattering compounds will fluctuate. Sulfur and iron are the two most common minerals to find, which will ruin beer in large enough quantities. The solution here is simply to find the most suitable source for brewing, which may require the purchase of purified water.
While most municipal sources are free of biological and physical contamination, the chemical purity can be more suspect. Most municipal sources are treated chemically with either chlorine or chloramines to maintain biological cleanliness. It is a necessary tradeoff to have a safe to drink supply, but brewers still must address it.
Chlorine can be eliminated in simple ways, such as simply letting it gas out of the water over time (usually overnight) or by pre-boiling the mash water. Chloramines are not as easily degraded. Chloramines will breakdown with the use of campden tablets, which will break the chloramines into calcium, water and bicarbonate. Failure to deal with chlorine or chloramines can result in yeast metabolizing these into harsh medicinal notes called chlorophenols. This is also true of using too much chlorine as a sanitizer.
Minerals in beer are numerous and many are flavor or stability neutral. We tend to concern ourselves with salts, calcium, carbonate, sulfate and certain trace minerals, used as yeast nutrients, such as zinc. In high amounts, many minerals can have a detrimental effect on beer such as inhibiting yeast, metallic flavors or haziness.
Most water supplies have some mineral content and do not need to be treated in order to make beer. This is why distilled water is not suitable for brewing because it lacks any supporting minerals and therefore inhibits enzymes and yeast. Some understanding of water minerals is important to understanding beer production and flavor.
Calcium is a necessary yeast nutrient and is abundant in most waters. Brewers add calcium in the form or gypsum and calcium carbonate. While we cannot directly measure the level of these in water, we can find their individual parts in the form of ions. It is these ions that react with the other ingredients to form flavor, chemical and biologic reactions within beer. Again, calcium is a major force in these reactions, reacting with malt phosphates to lower pH in both the mash and the boil, helping protein coagulation, and even preventing or slowing some color changes in wort. Besides a yeast nutrient, calcium also helps with yeast flocculation and beer maturation.
Every water district can tell you what sources are used for your area and can provide a water profile, which shows yearly averages of the minerals. Watch for high levels of iron, which can give a coin-like or metallic flavor or high levels of zinc, which is a haze inducer and can be toxic to yeast. Reading these profiles has been the subject of very comprehensive articles in both Zymurgy and Brew Your Own.
A survey of beer production around the world will find that softer waters tend to favor the production of lagers and darker ales while harder waters favor the production of paler ale styles with more hop presence.
Here are just a few of the major brewing centers:
Pilzen: With an average of just 7 mg/l of calcium, this is the softest water on earth. The Bohemian Pilsner style tastes very malty, in spite of the higher hopping rates than it’s sister, German Pilsner. Widely copied, this style is the gold standard and originator of the whole pilsner family.
Dortmund: The style of Dortmunder is widely misunderstood by brewers and judges alike. With calcium levels second only to Burton-on-Trent this water accents hops and presents a dry maltiness so prized in the Dortmunder style for its balance. Lingering hop bitterness, despite very low IBU’s can be directly attributed to the mineral content of the water.
Vienna: While Vienna lager is prized for its malty character, it is also supposed to have a relatively dry finish with a balance of hops. This city also has very hard water similar to Dortmund. As it turns out, nearly the same water profile is available in Mexico, especially Mexico City, where many classic examples of this style continue to be made.
London: Would you be surprised to find out that this city has some very soft water? With calcium levels at about 52 mg/l it has a profile that lowers the acidity of dark malts, leaving porter very round and drinkable.
When geographic differences are lined up, the major factor in brewing styles is water. Water is the one ingredient that can’t be imported and yet can be manipulated most by the brewer.