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What are the implications, if any, of brewing beer with water treated by a water softener? I've read lots of conflicting information and am looking for something more scientific and definitive.

{ asked by Matthew }


A concern with using softened water, whether all grain or extract, is that the large amount of sodium introduced will give a salty taste to the beer.

On the scientific perspective, Mr Wizard, at BYO writes

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.

If you can get a city water report or have your water tested, then that may help you decide if you will end up with too much sodium or not after passing it through the softener.

Assuming the water is fairly hard (otherwise it wouldn't need softening), it's better to skip the softener and use the hard water as is. This is fine if you're brewing extract, since the concentrations of hardness causing minerals are not so important, although if your bicarbonate or carbonate levels are over 300ppm then you might consider diluting, although taste the water first after boiling it and see.

If you're all grain brewing, then you'll need the water report, and use that as a basis to determine how much to dilute the water to get the dissolved minerals to acceptable levels. You dilute the water with distilled/deionized/RO water to reduce the overall amount of dissolved solids in the brewing liquor.

With all grain, it's really best to skip the softener, otherwise you'll have the counter-productive arrangement where calcium and magnesium are first removed by the softener and replaced by twice as much sodium, only for the brewer to then add back in more calcium and magnesium, since these are needed in the mash. By diluting your hard water you can end up with a workable water profile without introducing all the unwanted sodium.

{ answered by mdma }