Brewing Water Calculator
Considering that the vast majority of beer is composed of water, even if you do not plan on treating your water, you should at least know what is in your water so that you can match it with an appropriate beer style. Your starting point is with either tap water, bottled water, or water from another source such as a Reverse Osmosis (RO) system. From here you can use the Brewing Water Calculator to build-up your water profile with additives.
Information regarding the water profile of your tap water can be obtained from you water utility. For bottled water, this information is on the label.
Different beers ideally start with different water profiles. Some brewers even go as far as trying to match a water profile to the place where the beer was first brewed. For example, Pilsner in Pilsen and English Porter in London.
The six ions that are the most important when it comes to building a water profile for brewing beer are the following:
- Calcium (Ca2+) is usually the culprit in hard water. It is also an important yeast nutrient which is rarely found in wort. Calcium content in water reports will often be listed as “Hardness (Total) as CaCO3”. To convert to Calcium in mg/l, take the Hardness (Total) as CaCO3 and multiply by 0.4 (the Brewing Water Calculator will do this for you.) A minimum of 50 mg/l is recommended. Over 200 mg/l may taste “minerally”, but many excellent beers do start with higher.
- Magnesium (Mg2+) is a yeast nutrient which is also obtained from the wort. A minimum of 5 mg/l is recommended for healthy yeast. Magnesium levels above 30 mg/l can cause an unpleasant bitter taste.
- Sodium (Na+) has no minimum limit, but it can increase palate fullness. A maximum limit of 100 mg/l is recommended. Over 300 mg/l can produce a metallic taste.
- Bicarbonate (HCO3–) is the most important ion that causes alkalinity. Alkalinity is the capacity for water to resist acidification. In a water analysis, either Bicarbonate content is measured directly or indirectly as Total Alkalinity as CaCO3. To convert Bicarbonate to Total Alkalinity as CaCO3, multiply by 50/61 (the Brewing Water Calculator will do this for you.) Here are some considerations:
- Alkalinity is more important with regard to pH than the initial pH of your brewing water since low alkalinity makes the pH “moveable.”
- Often, Bicarbonate can be reduced by boiling first to allow the temporary hardness fraction of the bicarbonate to precipitate, but this takes time and energy.
- For pale beer, alkalinity of less than 100 mg/l is recommended. If alkalinity is too high, the pH of the mash may be too high which promotes astringency as well as lowering mash efficiency.
- For dark beer, alkalinity of up to 300 mg/l is recommended with large amounts of acidic (dark) malt in the grist bill. If alkalinity is too low, the pH of the mash may be too low and you run the risk of lowering mash efficiency.
- Sulfate (SO42-) enhances the bitterness in hops. For most types of beer, 50-150 mg/l is recommended. For hoppy beer, up to 400 mg/l is recommended.
- Chloride (Cl–) brings out the fullness and sweetness of malt. 50-150 mg/l is the recommended amount as more could produce an over-dominant sweetness. Chloride is different from Chlorine. Chlorine is extremely undesirable in brewing water, but can be removed by various methods.
In addition to the amount of the above ions, proportion is another metric. In particular, the proportion of Sulfate to Chloride. For Porters, Stouts, and Milds, the Chloride amount should be greater than the Sulfate amount (for maltiness.) For Pales, IPAs, and Bitters, the Sulfate amount should be greater than the Chloride amount (for hoppiness.)
Adjusting Brewing Water
Common salts used for brewing water treatment are the following:
- Sodium Chloride (Table Salt/Halite) use with caution to avoid salty beer. Avoid iodized salt and anti-caking agent.
- Calcium Sulfate (Gypsum) brings out the hoppiness of hops and lowers mash pH. Adding Calcium Sulfate to brewing water is called “Burtonisation” after the town of Burton-on-Trent in the UK which has water naturally high in Calcium Sulfate. Note that Calcium Sulfate dissolves better when the water is cold.
- Calcium Chloride is used to increase Calcium, Chlorides and lower mash pH.
- Magnesium Sulfate (Epsom Salt) is used to increase Magnesium and Sulfate levels in addition to lowering pH. Caution should be taken especially in regard to high Magnesium levels.
- Magnesium Chloride provides Magnesium and Chloride in addition to lowering pH. Observe cautions with regard to high Magnesium levels.
Note: parts per million (PPM) and milligrams per litre (mg/l) are extremely close to a one to one conversion when the solvent is water since:
PPM * solution density = mg/l
So, consider these two units the same for the purposes of the Brewing Water Calculator.