This column appears on page 14 of our April issue.
Sipping a pint of one of your favorite beers, it’s easy to appreciate the hop and malt flavors. Maybe you even note the fruity or spicy character from a distinct yeast strain, or the bracing acidity from a long secondary fermentation in barrels with lactic acid bacteria. But you probably aren’t thinking about the sulfate ions in the water accentuating the in-your-face hop bitterness of your IPA, or soft water facilitating the pale color and delicate bitterness in your glass of pilsner. Water is often overlooked, but it’s the most abundant ingredient in beer and plays an important role in determining its flavor.
Despite its importance in the brewing process, water’s effect on beer was poorly understood until the 19th century — but brewers did know that water in certain areas was better for making certain types of beer. The classic beer styles we know today are due in large part to the water profiles in the cities that made the styles famous: pilsner, dunkel, export lager, porter, and pale ale became prominent in certain areas because of the local water chemistry and how it affected the brewing process and its end flavor. Once upon a time, it was considered preposterous to brew a porter without Thames water in London. Luckily, things have changed.
European brewers traditionally used well water, but most breweries today (and nearly all in the U.S.) use their municipal water source, which can be a problem because of chlorine. If it is not removed, chlorine reacts with other ingredients in the beer and causes off-flavors. The most common way to remove chlorine is to run brewing water through an activated carbon filter — kind of like your tap water filters at home. Homebrewers sometimes use campden tablets or simply boil their water before letting it cool to the right temperature for the mash.
That might already sound like a lot of work, but removing chlorine is just the first step of preparing water for beer. A brewery still needs to consider the various minerals dissolved in the water, or its “hardness.” Hard water has a high mineral content while soft water has a lower one. Breaking things down further, temporary hardness is due to calcium and magnesium carbonates, and can be removed by boiling water. Permanent hardness is due to calcium and magnesium sulfates and can only be removed by reverse osmosis. Since boiling brewing water is not economical for a brewery, reverse osmosis (RO) is the most common way to deal with reducing hardness. Reverse osmosis plants are expensive to purchase and maintain and are typically only used by larger breweries or those using exceptionally unfavorable water hardness levels. This treatment produces water that is virtually free of ions—a blank canvas on which any water chemistry profile can then be constructed. In many areas, the local water is soft-to-moderately hard and suitable for brewing a wide range of beers as is.
For breweries that do soften their water, there are a couple of approaches. Some, like Stone Brewing Company, run a portion of their brewing water through reverse osmosis and then blend it back in with water that has only been carbon filtered. This gives them a moderately hard water profile that suits the generally hoppy beers that they brew. Societe Brewing is constructing a reverse osmosis plant for their soon to open brewery as well. They plan on blending back just enough carbon-filtered water to reduce the reactivity of the R.O. water, which can be corrosive to stainless steel. When using this approach, it is necessary to add mineral salts back to the water in the mash. This gives you the freedom to optimize mineral levels for specific beer recipes, or to replicate the water profile of a specific area or well. Brasserie d’Orval in Belgium, brewer of my favorite beer of the same name, used to have a well on the site of the abbey, but it is no longer a viable source of brewing water. They now use municipal water run through reverse osmosis, to which they add salts to achieve the same water chemistry as the original well. Breweries that do not soften their water will also often add some salts to make up for deficiencies in certain minerals.
But what mineral levels are desirable and how do they affect the flavors of your beer? Warning: if chemistry is a foreign language to you, this may sound a bit like gibberish. The most important mineral to the brewing process is calcium, which is critical for achieving a correct lowering (acidifying) of pH in the mash to the optimal range of about 5.1-5.5. When pH is out of the optimal range, enzymatic activity suffers and tannins can be excessively extracted, leading to less efficient conversion of malt sugars and harsher flavors in the finished beer. Calcium is also important for yeast flocculation, and break formation, which both lead to clearer beer. The high calcium levels in Burton On Trent, UK for example allowed the pioneering development of clearer pale ales in the 19th century.
Calcium is often added in the form of calcium sulfate (gypsum) or calcium chloride. Sulfate accentuates bitterness and is key to making good, hoppy pale ales. In the 19th century, brewers discovered that high levels of calcium and sulfate were key to the successful hoppy pale ales from Burton, and gypsum became a very common addition to brewing water for pale ales. Still, brewers today often add gypsum when brewing IPAs and other hoppy beers. Chloride adds roundness and fullness to malt character, and is desirable in higher levels for malty beers. The two minerals balance each other to some extent, and favoring one over the other will either accentuate hop or malt character in a beer. Sodium also adds fullness, but can quickly become overbearing in higher levels. Magnesium acts similarly to calcium but to a lesser degree and becomes detrimental to flavor in higher levels, so is not added as frequently as calcium. Carbonates work against calcium and have a strong ability to counter this drop in pH, which is why high-carbonate water is almost never good for brewing, except in the case of very dark beers in which the high percentage of dark roasted malts lend their own acidifying power to the mash. Munich, London, and Dublin all have higher carbonate levels in their water, which promoted the brewing of dark beers like dunkel lagers and porters.
The water in San Diego varies depending on the area, but it generally has a higher amount of sulphate than chloride, which might help explain why hop-forward beers have come to prominence in the area. Calcium is not particularly high, but high enough to make good beers without any additions. The water also has higher levels of carbonates, so brewing delicate, pale beers like blond ales and pilsners can be somewhat difficult. On the homebrew scale, purchasing RO water from the store and blending with tap water or adding salts is an easy way to get around this problem if you want to improve these types of beer. If you are curious about your specific water profile, the info is available online.
How much water does a brewery use? Obviously, the more beer you are brewing, the more water you need, but many factors affect total water consumption. The typical range for water consumption in a brewery is 5-12 pints of water for every pint of beer produced. You have to account for the amount of water absorbed in the grain from the mash, the amount boiled off, and the amount lost while moving the wort and then beer from the kettle to the fermentor and finally into bottles or kegs. On top of this, most water is actually used for cleaning and other areas of brewery operation, and not in the actual beer itself. The amount of water varies so widely because larger breweries typically use less water per beer due to economies of scale and expensive equipment that allows them to recycle and conserve water. Stone, for example, recycles some of its waste water from the brewery and treats it so that is can be recycled as cleaning water. It’s also common to recycle the water used in the heat exchanger to cool wort from boiling to fermentation temperature. This water, hot from absorbing the heat of the wort, is then used for mashing and sparging the next batch of beer. As technology improves, breweries are able to use less and less water to make beer.
The next time you have a beer, stop for a moment and consider the impact of water. From the historical rises of pilsner and porter, to the modern double IPAs of San Diego, water has been an ever present partner, and sometimes nemesis to brewers the world over.
Sam Tierney is a graduate of the Siebel Institute and Doemens World Beer Academy brewing technology diploma program. He currently works as a brewer at Firestone Walker Brewing Company and has recently passed the Certified Cicerone® exam. He geeks out on all things related to brewing, beer styles and beer history.