Brewing Water Adjustments

“Does your water taste good? Then it’s probably good for brewing.”

That quote embodies the mantra of homebrewers for decades when it came to the fourth ingredient in beer. Good water should yield good beer so long as the brewer has a good recipe and practices good brewing techniques. While this advice on the surface has merit, the salts naturally found in water can have a large impact on the final beer.

Water was always the final variable, that only the most seasoned homebrewers would think about altering. But over the last few years, as the hobby has matured, water has increasingly become a topic of conversation even for beginner and intermediate homebrewers. Why? Because brewing water matters.

From a brewer’s standpoint, there are really only a few ions (salts) that are found in common drinking water that we should concern ourselves with. To simplify things we can split these into two main groups: Cations and anions. Cations are simply positively charged ions while anions are negatively charged ions. So when you are adding brewing salts, you need to be aware that you are always going to be adding both cations and anions since salts always need to be neutrally charged. The charge of each ion is found as the superscript, so calcium [Ca²⁺] and magnesium [Mg²⁺] both carry a +2 charge while sodium [NA⁺] is only a +1 charge. Meanwhile carbonate [CO₃^2-] and sulfate [SO₄^2-] both have a -2 charge while chloride [Cl^–] has a -1 charge. So if you add calcium chloride, you are adding 2 parts chloride for every 1 part calcium.

Obtaining A Water Report

The first thing a brewer should always do is to find out what kind of water comes out of the tap. Is your water surface water (reservoir or lake) or ground (well) water? There are several ways for this to happen. If you are on a municipal water system it could be either a surface or ground source. Surface water most likely is going to be soft water since it takes years of water percolating through various soils and bedrock in order to dissolve higher levels of these salts into the water. Many municipal water departments will have water reports available either online or upon request. But the six ions of interest to brewers may not always be available on the municipal water reports. They may test for other factors such as bacteria, copper, lead, and other contaminants.

So what are your options if you are on a personal well or your municipal water department doesn’t test the six main ions of interest? Then it is time to get the water tested yourself. Luckily there are now plenty of ways to get the water tested yourself. The first avenue to look down is a laboratory service that tests for water ions. Here in the United States, Ward Labs offers a few options including the W-5A Brewer’s Test, which tests for 16 different values. You can visit their website: www.wardlab.com to purchase a test kit. If you are outside of the USA, you can still use Ward Labs, or you may find an agricultural water testing facility that can perform these tests for you.

Another great option is to purchase an at-home water testing kit like the ones produced by LaMotte or Industrial Test Systems. While the at-home water testing kits come with a much higher price tag, there are several distinct advantages. First, if you switch between various bottled water sources or if your municipal water department switches its source water among different wells or reservoirs, you can test for the 6 main ions regularly. Second, if you are in a homebrew club, a kit may be a great group purchase to benefit members of the club so everyone can share the kit to test their water. Finally, many of these at-home water test kits come with a pH meter. A pH meter may not be very useful for beginner to intermediate homebrewers, but as you grow in the hobby they can become much more relevant so that you can track the pH of the water to wort to beer.

Reading A Water Report

So once you have a water report for the water you plan to brew with, it is time to understand what those numbers represent. First thing you need to find out is the units which the numbers represent. Most water reports are given in ppm (parts per million) which is the same as mg/L. In other words, 30 ppm sodium is the same value as 30 mg/L sodium. In order to get a better picture of what that means, if you measured out and boiled off one liter of water, there would be that many milligrams of that specific ion left as a salt in the bottom of the pot. If for some reason your water report is not in ppm or mg/L, then I recommend that you convert those values to ppm since all brewing water calculators I have used will have this as their unit of choice. I won’t go into these conversions in this article, since they can be found online or as a feature in certain water calculators like Bru’n Water.

One part of the water report that people seem to struggle with most is the total hardness and the total alkalinity values. Both of these values are really just indicators and give you a rough idea of certain important characteristics of your water. Hardness and alkalinity are linked together in that they are really only significant for brewers using groundwater in regions with deposits of limestone, gypsum, and chalk. Since these are not straightforward values like the other key ions, let’s take those on first.

Total Hardness

This term was coined based on the level of work required to work up a lather in soap. Total hardness is basically the sum of the calcium and magnesium ions. The higher these levels, the harder it is to work up a soapy lather. When total hardness is provided in a water report, it usually reads “as ppm CaCO₃,” so you can’t just add up the calcium and magnesium ions to equal total hardness. Guidelines generally have soft water as 0-60 ppm as CaCO₃, 61-120 ppm as moderately hard, 121–180 ppm as hard and 181+ ppm as very hard.

While total hardness measures the calcium and magnesium levels, it can be classified into two categories: Temporary hardness and permanent hardness. Total hardness = temporary hardness + permanent hardness. Water that is considered hard will be high in ions, but temporary vs. permanent will distinguish what anions are found occurring with the calcium and magnesium, carbonate, or sulfate. Water with a high temporary hardness refers to a high level of carbonate. Temporary hardness is treatable and can be reduced by simply boiling the water, but a more in-depth look at treatment methods will be discussed in a follow-up article in this series. Water with a high permanent hardness refers to a high level of sulfate. As indicated in the name, permanent hardness really cannot be treated without either a reverse osmosis (RO) system or by diluting with distilled water.

Total Alkalinity

In it’s simplest form, total alkalinity is a measure of the water’s ability to resist a change in its pH. The more scientific definition of alkalinity is the quantity of acid required to lower the pH to 4.3. Carbonate [CO₃^2-], bicarbonate [HCO₃^–], and hydroxide [OH^–] ions are three typical ions in drinking water that will neutralize an acid. Often chemists will talk about this using the term buffering. Similar to total hardness, most water reports will provide total alkalinity value “as ppm CaCO₃.”

So why do we care about alkalinity? For brewers using water low in alkalinity, the mash is more susceptible to over acidification when highly roasted grains and crystal malts are added. Roasted malts and grains add a lot of acidity to the mash and can lead to more acidic beers, which may not be what they are looking for. Water high in alkalinity is going to be more difficult to drop the pH. For brewing water this is very important considering many brewers would like to have their mash pH down around 5.2–5.4 and their wort pH around 5.3–5.5. If there isn’t a lot of darker roasted crystal malts and grains added, then highly alkaline water may lead to high pH beers. This can cause problems with wort darkening during the boil and off flavors such as increased diacetyl levels.

Residual alkalinity is the term coined to describe the net sum when the brewing water and the malt make-up are combined together. This value will help brewers gain a better understanding of how all the key factors fit together, or how adding darker malts or lactic acid or calcium chloride, can affect the mash pH and further downstream, the final product. As Burton-On Trent brewers found, just because you have highly alkaline brewing water, it doesn’t always mean that you cannot brew a pale beer. I will discuss much more information about residual alkalinity in the next article in this series.

Water pH

The pH of the water in your water report is fairly insignificant. While it may be a good thing to know and several calculators will call for this value, there is not always a direct correlation between the water’s alkalinity level and the water’s pH. So unless the pH of the water is fairly high, where it is in the unsafe to drink zone, then you should not worry too much about the water’s pH. But once water and grains mix, then pH starts to become much more significant.

Key Ions

Calcium [Ca²⁺]
Recommended water levels 30–150 ppm. Calcium is probably the most important cation to be found in brewing water. Calcium is beneficial in most steps of the brewing phase. Its benefits have been noted from its positive affect on alpha amylase enzymes in the mash to the boil to fermentation and yeast flocculation. So if you are starting with RO, distilled or very soft water, you should look to boost your calcium levels with one of several calcium containing salts and bases such as calcium chloride (CaCl₂), gypsum (CaSO₄), chalk (CaCO₃), or lime (CaOH).

Magnesium [Mg²⁺]
Recommended water levels 5–30 ppm. Magnesium’s benefits are similar in nature to those of calcium, aiding in several key steps during the mash. One important detail though is that magnesium will see a large boost in the mash as it occurs naturally in malt. It also can have an effect on the flavor profile of the beer, adding a bitterness at lower levels and astringency at higher levels. It is recommended that you do not exceed 50 ppm Mg in your brewing water and excessive amounts are also cited as causing a laxative effect. Epsom salts (MgSO₄) are the most common way for brewers to boost their Mg levels.

Sodium [Na⁺]
Recommended water levels 0–50 ppm. Sodium is not known to have any beneficial effects on the mash or fermentation, but sodium does affect the mouthfeel of the beer. This means you can add sodium at any point during the production of your beer, not just on brew day. While we recommend 50 ppm as the max level, certain beer styles may benefit from higher levels of sodium from table salt, like Gose, and can be a nice touch in darker beers like stouts. Table salt (NaCl) and baking soda (Na₂CO₃) are the two most common ways for homebrewers to boost their sodium.

Bicarbonate [HCO₃^–]/Carbonate [CO₃^2-]
Recommended water levels vary: 0-50 ppm for pale beers; 50–150 for amber to brown color beers; 150–300 ppm for dark to jet-black beers. This is the ion that brewers tend to focus on the most due to its extreme importance in determining the pH of the mash and beer and for the most part can be considered an unwanted ion in all but darker colored beers. Carbonate will precipitate out in the presence of calcium which is an important factor in why it is called temporary hardness. The effects of carbonate will be discussed at length later in this series of articles. Baking soda (Na₂CO₃) and chalk (CaCO₃) are commonly used to boost carbonate levels.

Chloride [Cl^–]
Recommended water levels 0-300 ppm. Chloride has been cited as a beneficial ion during the mash, but not required. Chloride has traditionally been used by brewers to boost the mouthfeel and creaminess of malt-forward, beers but recently homebrewers have been using chloride in certain IPAs to enhance the character of the beer. Calcium chloride (CaCl₂) and table salt (NaCl) are commonly used to boost chloride levels.

Sulfate [SO₄^2-]
Recommended water levels 20-150 ppm. For beers in which brewers are looking for a hop bite, brewers will go up to 350 ppm in order to “Burtonize” the water. Above 400 ppm, the effects of sulfate will start to turn on the brewer, providing a harshness that should be avoided. One key component is that certain water tests will provide sulfate levels “as-S.” To convert that value to actual sulfate levels, simply multiply by 3. Gypsum (CaSO₄), epsom salts (MgSO₄) are two common salts used to boost sulfate levels.

Other Ions

There are a few other ions that will be found in a water report worthy of noting, but nothing that brewers would ever add. In a worst case scenario, brewing water would need to be supplemented with RO water or distilled water to bring these levels back down into an acceptable range.

Potassium [K⁺] Should not exceed 10 ppm.
Iron [Fe] Should not exceed 0.1 ppm.
Manganese [Mn] Should not exceed 0.05 ppm
Nitrate [NO₃^–] Should not exceed 44 ppm. Similar to sulfur, sometimes provided “as-N.” If so, simply multiply value by 4.4 to obtain actual ppm nitrates.

Chlorine and Fluoride

If you are on a municipal water system, then your water probably is treated with some form of chlorine. This is a serious problem for brewers as chlorine can be converted into cholorophenol. Chlorophenols provide a medicinal/mouthwash flavor in even very low levels, being detected starting at just 10 parts per billion (ppb). Luckily chlorine is an issue that is easily treated by even beginner brewers.

There is good news and bad news if your municipal water is treated with fluoride. The bad news is that an RO water system would be required to remove its presence. The good news is that fluoride ultimately has little impact on the final beer.

Written by Dave Green