Beer Science: Hard Water vs. Soft Water in Beer

Beer-making is part science and part craft. From upstart indie micro-outfits to breweries going back generations, anyone serious about making good beer knows it’s a balance of many factors.

Yet, at its core, beer is really about four key elements: grain, hops, yeast, and water. And from these basic components, vastly different drinking experiences can be created. This means you can end up with anything from a light, refreshing, golden pale ale to a dark, malty, chocolatey stout. Of course, this is partly due to the techniques and processes used, but chemistry is also important. So if you want to know what affects brewing beer, you have to look at what goes into it first.

The Importance of Beer’s Four Key Ingredients

Part of understanding the science of beer is understanding the exact role that grains, hops, yeast, and water play.

In essence, grains — malted barley, wheat, rye, rice, corn, or oats — are responsible for much of the look and taste of a beer, plus they contain the sugar that ferments it into alcohol. Hops keep the brew fresh, help maintain that satisfyingly foamy head, and bring a balancing bitterness into the beer flavor profile. They are also what give it that earthy aroma. Yeast is a key part of the fermentation and carbonation process, plus it adds its own flavors, many of which are attributed to families of fruits.

And what about humble water? For one thing, it’s not so humble — it plays a huge part in the taste of beer. And much of this comes down to whether the water used in brewing is “hard” or “soft.” But what do brewers mean by these terms?

What’s the Difference Between Hard and Soft Water?

There’s a misconception that hard water contains a lot of minerals and soft water doesn’t. But in fact, each type contains different minerals that affect whether it’s classified as hard or soft.

For instance, when rain falls from the sky, it’s soft, as its key minerals are the electrolytes potassium and sodium. But when it seeps into the ground and makes its way through soil and bedrock, it begins to collect groundwater minerals that make it hard. These include calcium, magnesium, manganese, chalk, and lime.

Does Water Make a Difference in Beer?

All of this is crucial to beer, as different minerals can impact its flavor, style, smell, color, and texture. That’s because the hardness or softness of water affects a beer’s pH levels (acid or alkaline), which in turn affects the chemical processes of brewing so much that it can produce totally different varieties of the drink.

To brush up on your high school chemistry, pH levels are on a scale of 0 to 14. A pH level of less than 7 is acidic, while more than 7 is alkaline. For instance, hard water is alkaline, with a pH of around 8. Soft water is acidic, with a pH of about 6.

This is why using hard or soft water significantly affects how a beer turns out. For instance, hard (alkaline) water creates dark, hoppy, textured beers such as porters, stouts, and the heavier end of lagers. Flavor profiles might include nuts, chocolate, coffee, malt, roasted, and creamy. These beers go well with heavy meats, cheeses, and smoky foods.

In contrast, beers made in regions with soft (acidic) water are less heavy and tend toward a cleaner, crisper, bitterer taste that can be quite sharp. These include pilsners, IPAs, and lighter lagers. The flavor profile can vary, but it may include tropical or citrus fruits, flowers, herbs, or spices. These beers are a good match for seafood, salads, and white meats like chicken.

Can the State You Live In Influence the Beer You Drink?

Of course, breweries today use techniques to manipulate the pH levels in their water, meaning the type of beer they can make is no longer restricted by geography. Yet because of the traditional impact of pH levels on brewing, different parts of the U.S. can still be associated with different types of beer.

So when Thrillist decided to pick an official state beer for each American state, the criteria was that each beer had to have originated from that place and also be popular with the residents. And it turns out some of their choices matched the relative hardness or softness of the water in each state.

For instance, Thrillist picked ales, stouts, and dark lagers such as Shiner Bock for hard water states such as Mississippi, Illinois, and Texas. In contrast, it selected fruit beers, pale ales, and IPAs such as Heady Topper for soft water states like Alabama, North Carolina, and Vermont.

None of this is an exact science, of course. But it certainly shows how crucial water is to the beer-making process. It’s not some insignificant or lesser ingredient compared to grain, hops, and yeast — it’s a core element that can make the difference between a summery pale ale enjoyed in your yard or a heavy stout sipped on a winter’s night by the fireplace.

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