Dear Mr. Wizard,

Would you please enlighten me on brewing with softened water? Also, how much salt does a softener add to 5 gallons of liquor? Should I still add some amount of salt when called for in a recipe? I have well water and brew all-grain. I have brewed with a variety of waters and am left unclear by any material I have ever read regarding use of water softeners.

Robert R. Heinlein

via email

Mr. Wizard replies:

Water is said to possess "hardness" when it contains ions of calcium and/or magnesium. I have never really understood the origins of this term, since hard water feels as soft as, well, soft water. Hardness is divided into two categories; permanent and temporary hardness. The latter type can be removed when water containing calcium or magnesium ions and carbonate ions is boiled. When heated the calcium and magnesium ions react with carbonate ions to form calcium or magnesium carbonate, also called scale. This scale is frequently seen on tea pots and water faucets in homes with hard water. Permanent hardness is the amount of calcium and magnesium that remains in water after boiling. It is possible for a water sample to contain both temporary and permanent hardness.

Water softeners work by replacing calcium and magnesium ions in water with sodium. Two atoms of sodium are added for every atom of calcium or magnesium removed from the water. This means that if your well water has 100 ppm (mg/L) of calcium and 20 ppm of magnesium that the softened water will contain a whopping 240 ppm of sodium. As far as brewing water is concerned, sodium adds palate fullness and sweetness up to about 100 ppm. At higher concentrations, sodium gives beer a salty flavor.

The real problem with using softened water for brewing is that most homes equipped with water softeners have harder than average water. Thus, the water produced by the softener is in turn very high in sodium. For this reason softened water is often only used for utility water (water for showers, toilets, washing machines and the like). Water piped to sink faucets bypasses the softener. The above example of 100 ppm calcium and 20 ppm magnesium would most likely not warrant a home water softener.

Let’s assume that you do not have abnormally hard water, but simply have a softener. As long as the sodium does not lend a salty flavor to your water or beer you can use it for brewing. The "salts" listed in most recipes are calcium sulfate and/or calcium chloride. You certainly would want to add these since calcium is required for pH adjustment in the mash, is a co-factor for alpha-amylase, aids in trub formation and also helps yeast cells flocculate at the end of fermentation.

If you actually did use softened water for brewing as described above this is what happens. 1) You remove calcium and magnesium and replace it with sodium. 2) You add calcium back to the water because calcium is important for brewing.

In my opinion, this seems like a round-about way to add sodium! Most breweries were historically located near good wells and it might be your signature touch to simply use your well water as is and not to worry much about water softeners.

The more likely case is that you have a water softener because you have hard water. I would not recommend using softened water from well water that is indeed hard. Homes with hard water are easy to spot because of white mineral deposits near water taps. Unfortunately, most hard waters in North America come from limestone aquifers and limestone is calcium carbonate. The only beer really well-suited to these waters are dark ales and lagers, for example porter, stout and dunkel. The preferred hard water type for brewing lighter colored beers, like pale ale, is hard water from a gypseous aquifer — gypsum is calcium sulfate.

Water may appear to be clear and pure but it contains a lot of confusing cloudy, details when examined at the atomic level. I am a strong advocate of the KISS (Keep It Simple, Stupid) approach when it comes to water. I either prefer using the local water supply as is, with chlorine removed with a charcoal filter when applicable. Alternately, you can use de-ionized water or distilled water from the supermaket and add various salts to mold the water into the type needed for the particular task. If it is possible, get an analysis of your well water and determine what type of water you have. Based on this information you can make a more calculated approach to water treatment. Steve Parkes and Don Million offer more detailed information on adjusting brewing water in the January-February 2002 issue of BYO.

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