An In-Depth Look at Water Composition for Brewing Beer
Water is just one of the four primary ingredients in beer, but considering that water may constitute up to 95% of beer’s content, brewers are well aware of the importance of good brewing water. The various minerals and salts found in water used for brewing can accentuate beer flavors or contribute undesirable flavor components. In many cases, water chemistry is key in the flavor profile of a classic beer style.
For the majority of folks who brew their own beer at home, the issue is not nearly as critical because good beer can be made with average tap water. A very general rule says: “If your water tastes good, so will your beer”. It should be noted that this general rule pertains solely to malt extract-based homebrews, not beer made from all grain. Another general rules says that any water, regardless of its source -be it a lake, a river or an artesian well, can be manipulated to match the chemical/mineral profile of another source.
Hard Facts, Fluid Concepts
Water can be considered either “soft” or “hard”. Soft water is very low in mineral content and hard water is very high in mineral content. When it comes to brewing, soft water is generally preferred over hard water because it’s a lot easier to add minerals to the water than it is to remove them.
If you have hard water, there’s the additional concept of temporary hardness versus permanent hardness. The former refers to the presence of soluble bicarbonates of calcium and magnesium in the water which precipitate out when the water is boiled. The latter refers to water hardness after the water has been boiled and all the non-precipitating minerals are still there (precipitation occurs when mineral ions are attracted to one another, bond together, and then fall out of solution as a sediment).
Mineral ions, simply put, are components of mineral salts that dissolve in water. And because ions have either a positive or negative charge, they are electrically attracted to the principal ingredients used to make beer (malt, hops, and so on) the effects of which can be tasted in the finished beer.
At least seven principal ions exert a substantial influence on the beer-making process. The following list provides a brief description of these ions and their influences (the term ppm means parts per million):
- Calcium: lowers pH and assists enzyme action during mashing.
- Carbonate: halts enzyme action and promotes harsh flavor derived from hops.
- Chloride: at high levels (250 ppm+) may enhance the sweetness of beer.
- Bicarbonate: halts enzyme action and promotes harsh flavor derived from hops.
- Magnesium: lowers pH; is an important yeast nutrient at 10 – 20 ppm.
- Sodium: has no chemical effect; may impart “roundness” to beer flavor.
- Sulfate: has no chemical effect; may impart harsh dryness when used with sodium.
Brewers occasionally use other mineral salts to adjust the pH level of their mashing water or increase the ion profile of their brewing water. These include:
- Calcium Carbonate: More commonly known as chalk, this raises pH.
- Calcium Sulfate: More commonly known as gypsum, this lowers pH.
- Magnesium Sulfate: More commonly known as Epsom salt, this lowers pH.
- Sodium Chloride: More commonly known as table salt, this has no effect on pH.
The importance of a specific aspect of water composition -namely pH balance- becomes much more critical when homebrewers begin mashing their own grains. pH balance refers to the acidity and alkalinity level in various liquids. This balance is measured on a fourteen-point pH scale. A rating of 1–6 on this scale is acidic, 8–14 is alkaline. A pH of 7 is considered neutral, or balanced (pH is an abbreviation for potential Hydrogen). pH is easily measured with pH test strips or pH meters.
The pH balance in brewing water, for beginners, is for the most part, irrelevant, but when brewers progress to mashing procedures, pH levels in mashing water is absolutely critical. At the more advanced levels of homebrewing, when a given water source is determined to be either acidic or alkaline, you may need to add either gypsum or calcium carbonate to the water to adjust to the desired pH level; gypsum lowers pH, calcium carbonate raises it.
Speaking in very general terms, slightly acidic water is preferred over alkaline water; a pH level of 5.5 is considered best for mashing. Slightly alkaline water is acceptable for brewing dark beers, however, because dark malts’ acidity strikes a natural balance with the alkaline profile of the water.