The Elements of Brewing Water

Barley, hops, and yeast get all the attention, but water is the main ingredient in beer. The ions in your water supply directly affect the flavor of your beer — for good and ill.

The presence of calcium sulfate (CaSO4) or calcium carbonate (CaCO3) can give beer a slightly astringent or bitter flavor. Calcium (Ca+2) and magnesium (Mg+2) in large amounts will produce a metallic flavor. Too much sodium (Na+) can start to give beer a salty flavor. Chloride (Cl-) alone or combined with sodium gives a more full-bodied flavor.

These ions also affect the pH of your water. A high pH in the mash can cause poor extraction rates, darken the wort, and leach more tannins into your mash.

Unless your water is simply not potable, it can make good beer. Even great beer. But maybe not lighter beer. Maybe not darker beer. It depends on what beers your water is suitable for. There is no ideal water — different beers need different qualities in water.

Probably the most emulated brewing water is that of Burton-on-Trent, England, home of classic pale-ale brewers such as Bass. It has a lot of sulfate and calcium in it plus a fair amount of chloride. This makes ideal brewing water for light ales. Another highly replicated brewing water is from Pilsen, the Czech town known for pilsner-style lagers. This water source is notably lacking in calcium, sulfates, and other ions. These two waters represent the extremes of brewing water. The Burton water is excessively hard and the Pilsen water is exceedingly soft.

Hardness is a measure of the calcium and magnesium content in water. The amount of hardness in water is referred to as total hardness, the presence of both permanent hardness and temporary hardness. Permanent hardness is a measure of calcium sulfate and calcium chloride and can’t be removed by boiling. Temporary hardness is hardness that can be removed by boiling. It mostly has to do with the bicarbonate ion in association with calcium carbonate.

Hardness, either temporary or permanent, is not intrinsically good or bad. For pale ales, permanent hardness is good. For dark beers, temporary hardness is better. For Pilsen-style beers, neither is good.

If you understand the basics of water chemistry, you can tailor your water to match the beer you like to brew — or change your beer brewing to match your water.

The Hard Truth
The most basic discussion about water involves hardness. The harder the water, the more ions it contains. If you are serious about your brewing water, the first thing you must do is get a copy of the water-quality sheet from your local water department. Also inquire as to the number of water sources and when they are used. Some municipalities use certain water in the day and different water at night. Some places are on well water at certain times of the year and recycled sewage treatment water at other times of the year. You should obtain information on all the waters used and the times of use.

Water hardness is expressed in many ways, but the most common measurement used in the United States is parts per million, or ppm. Water is loosely categorized in increments of 100.

For example water with hardness rated as zero to 100 ppm is considered very soft to soft. Ratings of 100 to 200 ppm are soft to medium, 200 to 300 ppm are medium to moderately hard, 300 to 400 ppm are moderately hard to hard, and 400 to 500 ppm are hard to very hard.

You must also determine whether or not the water is permanently hard or temporarily hard.

Water charts usually point this out. Most report the hardness in terms of total hardness and temporary hardness. If the temporary hardness level is close to the total hardness level, then the water has a large amount of temporary hardness. For example if you have a water sheet that reports total hardness as 425 ppm and temporary hardness as 300 ppm, the water is more in the category of temporary hardness.

The Softer Side of Water

Once you know the type of water you’re using, you can make the beer to fit the style of water or you can adjust the water to fit the type of beer.

In general soft water is rare but is good for light lager styles. If you have soft water, consider yourself lucky. It is far easier to add minerals to your water than to take them away. Water that comes from a water softener is not acceptable for brewing. Water softeners trade ions, taking away calcium, sulfate, and carbonate, but they do this by replacing them with sodium and chloride ions. This is better for bathing but not good for brewing.

If you have true soft water, anything lower than 150 ppm, then you can brew any style of beer you want. You can brew light pilsners without altering the water at all, and you can brew the rest of the styles by adding minerals to your water.

Hard water is a bit more tricky to deal with. However, there are several ways to attack the problem of removing minerals from your water. Which you use depends on how much time and money you want to invest.

Boiling: Fortunately there is a very effective, simple, and cheap way to deal with temporarily hard water. If your water is loaded with calcium carbonate, you can reduce the amount by as much as half simply by boiling the water, letting it sit for a half hour, and then decanting it.

Most compounds become more soluble as they are heated; sugar and salt are two common examples. Calcium carbonate reacts differently. If you heat a calcium carbonate solution, instead of dissolving it will band together and fall to the bottom of the container. This serves you well, because you can simply decant the water off the top and greatly improve your brewing water. Chemists call this an endothermic reaction; you can call it good fortune.

Boiling water also removes chlorine. Chlorine mixed with polyphenols makes nasty, bitter compounds. If you can smell chlorine in your tap water, boil the water. If not, don’t worry about it.

Reverse Osmosis: There are other ways to purge chemicals out of the water. One way that is creating quite a bit of interest among homebrewers and professional brewers alike is a technique called reverse osmosis, commonly known as R/O. Small R/O systems are not too expensive; however they are not exceedingly cheap either. They are very efficient at cleaning water. With an R/O system you can have virtually ion-free water. If removing ions to create an ideal water is important to you, you should consider this for your brewing want/need list.

To take advantage of the technology without buying a system, you can buy R/O water. You might have to do some looking, but some supermarkets have the R/O system set up right in the store.

Distillation: One final method for cleaning up water is to distill it. Simply speaking, you boil the water and then trap the water vapor, condense it, and collect it. For home use it is not hard to make such a device, but the energy cost is pretty high to use it. A related problem is convincing your local ATF agent that you only use this device to purify your water. However, most stores carry packaged water labeled distilled water. It’s the same stuff that goes into your car battery and your iron.

Like R/O, distillation leaves water virtually free of minerals. This enables you to start from scratch for a recipe.

Boiling the water will not get rid of all the minerals, but it is very effective at reducing your temporary hardness level. However, you will have to guess at your overall hardness. While this is not an exact rule, you can get some idea of how much calcium carbonate was knocked out of the water by looking at the amount of white matter left behind. If the bottom of the kettle has a consistent white covering, the water was very hard and you knocked a lot out of solution. If there is only a slightly hazy white bottom, then the water was only moderately hard, or you removed a fair amount but not all.

Anything less and you either didn’t remove much or the water was not hard to begin with (the calcium knocked out of slightly hard water will be hard to see).

Making Water Harder
You can make your water harder by adding several types of minerals. The most common of these minerals is gypsum (calcium sulfate). Other minerals that are used are calcium carbonate (used for dark beers) and calcium chloride. The amount you add will depend on your water source and the recipe you are emulating.

Calcium sulfate: Gypsum is added to give more permanent hardness to the water being used. It does not dissolve all that easily, so it is important that it is vigilantly stirred if you are adding the water before the mash. The flavor that gypsum gives has been described as dry, slightly astringent, and crisp. This would be used to emulate many of the lighter- to medium-bodied ales.

Calcium carbonate: Calcium carbonate is used to add temporary hardness. In general it is used to help reduce the mash pH in dark beers.

Calcium chloride: Calcium chloride is used to introduce permanent hardness and a bit of chloride ion into the beer. It can be used in conjunction with gypsum or as a substitute. The purported advantage over gypsum is it gives the beer, via the chloride ion, a more full-bodied flavor and a slight sweetness. This should probably be used in amounts less than 250 ppm.

Magnesium: Magnesium is certainly a flavor player in some of the English ales. However, most people shy away from using it. If you have water that is more than 100 ppm magnesium, you will most likely be better off seeking another water source. Magnesium is related to calcium and causes a similar reaction. When it is in water with carbonate ions, it makes the water more alkaline than calcium would. That’s because magnesium carbonate is about 3.5 times more soluble than calcium carbonate.

Now that you have a bit of water chemistry under your belt, you will be better able to make the perfect water for your perfect beer. This will also give you one more control over your brewing process, which will help you to re-create a beer recipe. It might also help explain why you have a perfect beer recipe where you used to live and now you just can’t seem to re-create that beer. If this is a problem, you should get the water quality sheets from both locations and check for differences in the water.

Issue: April 1999