Brewing Water Chemistry – What Kind of Water is Best?

Close up water

Most brewers can make good beer without thinking much about their water source and brewing water chemistry. As long as the water is clean and tastes good, the beer usually will come out okay. Water chemistry may seem intimidating, but with a little knowledge on how grains and minerals come together in the mash, we can turn good beer into great beer.

When it comes to water chemistry, it’s very important to know what makes up the water you are starting with. This is called your base water profile. You can’t adjust your water if you don’t know where you’re starting from. It’s like trying to get driving directions—if you don’t know where you’re driving from, you can’t get effective directions to where you’re going.

Water chemistry has been quintessential to the beer styles developed over the ages. Whether it’s stouts in Ireland, porters in England or pilsners in Austria, water profile influences the final beer and helps shape what it becomes.

Analyzing Tap Water for Brewing

Many brewers get their water straight from the tap. If it’s good enough to drink, it’s usually suitable for brewing. The two most common sources of tap water are municipal water and well water. Within both of these subsets, water chemistry can vary dramatically.

Municipal water is usually sourced from reservoirs, lakes, and rivers. The specific source can change from season to season. The water is processed and treated by the municipality. This water regularly contains chloramine or chlorine to keep it safe to drink. These disinfectants will require the brewer to treat their water with campden before brewing.

Well water is another common brewing water source. This water is usually more consistent than municipal water because the source never changes. Despite the consistency, well water usually contains more dissolved minerals, making the water hard.

Water that is too hard or too alkaline—opposites—both can cause problems for brewers. But they’re able to be worked around, both by treating the water and the malt bill, which is how we’ve gotten the wide range of beer styles from across the globe. Brewers might have pre-boiled their water to reduce hardness, like those in England for the IPAs, or added salts to increase it like in PIlsen.

Regardless of your water source, you have to know your base water profile. For municipal water sources, you can get this by contacting your local municipality. The water report will usually be an average over a period. The reported water will most likely be different than what eventually comes out of your tap, but the report will give you a good estimate of what you’re working with.

Well water users don’t have the luxury of constant water analyzation and reporting. A water report will need to be obtained by sending the water to a lab that can analyze it. In the US, Ward Labs does this relatively cheaply. Municipal water users might consider lab analysis as well, as it will be more accurate than the report provided by the municipality.

If the brewer doesn’t want to get into the specifics of their tap water, they should at least treat their water with campden. Chlorine and chloramine can react in the brewing process and create chlorophenol, which causes off flavors. One campden tablet (potassium or sodium metabisulfite) is enough to treat 20 gallons of brewing water. Simply crush the tablet and stir in water, dissolving it entirely before using it for brewing. The de-chlorination will be complete within minutes.

Other Sources of Brewing Water

For those who don’t like the taste of their tap water or can’t get it tested, there are other options. A brewer can make use of reverse osmosis water, distilled water, or bottled water.

Reverse osmosis (RO) water is a common choice among brewers. You can buy RO water from a store or create it at home with a filter. There are very few dissolved minerals in RO water, making it easy to add minerals to achieve your desired profile. Distilled water works similarly but you can’t easily produce it at home so you’ll have to buy it.

Bottled water bought from the store is also a viable option. This water may be spring water or bottled municipal water. Brewers should ask the water provider for the water profile. Keep in mind that bottled water may still contain chlorine or chloramine.

How to Read a Water Report?

A water report contains a lot of information, not all of it relevant for brewing purposes. The ions that influence beer are calcium, magnesium, sodium, sulfate, chloride, and bicarbonate. Concentrations are usually noted as parts per million (ppm) or mg/L. These mean the same thing and are interchangeable.

Calcium (Ca) is very important for many reactions in the brewing process. All-grain brewers with calcium-deficient brewing water will have low efficiency in the mash. It’s also important for yeast health as well as the flavor and stability of the final beer. Brewers should target their calcium ppm to at least 50 but no more than 200.

Magnesium (Mg) is a yeast nutrient in small quantities. Brewers should target their magnesium ppm to be less than 50.

Sodium (Na) is not a necessary ion for brewing, but it can contribute body and flavor to the beer. Many brewers do not add sodium to their brewing water and prefer to enhance the body with other minerals. At levels above 150 ppm, you’ll get unwanted salty tastes in your final product.

Sulfate (SO4) is a popular topic of discussion when it comes to hoppy and bitter beers. The levels of sulfate in beer directly affect how the drinker perceives crispness, bitterness, and hop flavor. Brewers will target levels up to 200 ppm for hoppy beers but some may go higher.

Chloride (Cl) is similar to sulfate in that it correlates directly to flavor and body in the final beer. High levels of chloride are used to accentuate malt flavor and fullness. Levels of up to 200 ppm are used.

Bicarbonate (HCO3) and carbonate (CO3) are very important when it comes to the chemistry and pH of the mash. Hard water is classified by carbonate concentrations greater than 100 ppm. Hard water will make it difficult to brew pale beers without acidification of the mash.

After analyzing your report you may find yourself in a situation where your water does not contain the concentration that you need for your desired water profile. There are various brewing salts that you can add to your water to increase these concentrations. The most popular brewing salts used are gypsum (CaSO4), calcium chloride (CaCl2), Epsom salt (MgSO4) and magnesium chloride (MgCl2).

The Importance of pH in the Mash

For all-grain brewers, a proper mash is important for efficiency and flavor. The desired mash pH is 5.25.6. Grains, especially dark grains, are acidic and lower the mash pH but the buffering power of carbonates will inhibit this. The addition of brewing salts will also lower the pH of the mash. If the grains and salts don’t do the job of lowering the pH into the desired range, acids can be used.

The main acid used by brewers for acidification of the mash is lactic acid. This is available in most homebrew stores. The taste threshold is purportedly 1.5ml/gallon for lactic acid. If more than 1.5ml/gallon is required to get to proper mash pH, dilution of the brewing water may be required. The brewer can also use stronger acids like phosphoric acid.

Mash pH cannot be calculated and must be estimated using brewing software. The software uses your base water profile, grain bill, and salt additions to estimate your mash pH. Using this estimation, you can find out if you need to acidify your mash. Popular and reputable software includes Bru’n Water, EZ Water, and Brewer’s Friend. Different software may use different models for estimation, so it’s best to estimate using software and then verify using a pH meter.

Brewing a NEIPA, a Water Chemistry Example using Bru’n Water

In this example, we will be brewing a 5-gallon, no-sparge full volume BIAB batch of New England IPA using tap water for which we have obtained a water report. The following image shows a common water report with all the information required for brewing.

Water report

This report shows us that we have a low amount of minerals and low hardness. This is ideal water for building up into any profile. The grain bill and desired water profile are as follows.

Grain Bill:

Pilsner7.5lbs (65%)2L
Flaked Oats2.25lbs (20%)1L
White Wheat Malt1.75lbs (15%)2.4L

Desired Water Profile:


Now that we have the above information, we can open up Bru’n Water and plug it all in. On the first tab, we will provide information from our base water profile.

Bru’n Water profile

On the third tab, we will then enter all of the grain bill information. Bru’n Water will use the bill in combination with the base water profile to estimate the mash pH. With this grain bill, our mash pH has come out to be a bit higher than our desired range of 5.25.6.

Mash pH result

On the fourth tab, we can then enter our desired water profile and the software will calculate our target finished water adjustment. We can see that we need to add some minerals to get up to our target concentrations.

target water concentrations

Trial and error is then used to adjust the mineral additions until we have reached the desired ppm. The mineral additions have been changed to 1g/gallon of gypsum and .8g/gallon of calcium chloride. This gets us up to our desired concentrations; don’t worry about a differential of a few ppm. The mineral additions lower the pH sufficiently so we won’t need to acidify any further with lactic acid.

final water and pH estimations

Now that we have put our recipe through Bru’n Water, we know what we need to add to take our brew to the next level. Simply treat the 7 gallons of mash water with 7 grams of gypsum and 5.6 grams of calcium chloride prior to mashing in.

Our new water profile will react with the grains and settle at the perfect mash pH. A proper mash, seasoned with the correct amount of brewing salts, will give us a great head start for brewing the perfect NEIPA.

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