I have been reading a lot about home brewing. I'm planning actually to build an electronic 5 gallon brewery. Could anyone provide a short explanation when (mashing, boiling ?!), why and how much to use of the following salts?

Gypsum / Calcium Sulphate (CaS04) 
Calcium Chloride (CaCl2)
Pure / Unscented Epsom Salt (MgS04)
Chalk / Calcium Carbonate (CaC03)
Baking Soda (NaHC03)
Non-Iodized salt / Pickling salt / Kosher salt (NaCl)

Are they really necessary? :/


  • 1
    I'd like to add a follow-up: What is the effect of adding salts on PH? Commented Mar 26, 2014 at 14:20
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    Ionic concentrations will change pH. :) Sorry to be a bit flip, but I'm not sure there's a concise way to answer that. I'm just starting into the Brewer's Publications book /Water/, and they have at least a chapter devoted to mash pH and water chemistry.
    – jsled
    Commented Mar 26, 2014 at 19:18

2 Answers 2


The core question is … Why? Different ions lead to different perceived properties in the finished beer; for one example: higher concentrations of chloride emphasize malt character, whereas higher concentrations of sulfate emphasize hop character and dryness.

When? Both in the mash and in the sparge water, mostly based on the ratio in volume, with some caveats.

How much? Impossible to say without knowing both your current and desired water profile. Your current profile might be obtainable from your municipal water district's report, or you can send a sample away for analysis. Your desired profile is going to be based primarily on the style of beer you want. How much of each salt (or acid or other chemical) you need to achieve the ionic profile you desire is really up to your source water and in some cases your grain bill as well.

Both "when?" and "how much?" are answers that involve a lot of computation; spreadsheets (Bru'n Water, EZWater, &c.) or other brewing software are nearly essential to these tasks.

If you're just getting started, don't worry about water chemistry, except to filter it for major contaminants and for chlorine/chloramines; if your water smells and tastes good, then brew with it. Nearly everything else is more important to making good beer as a beginner, especially fermentation temperature control and yeast health (appropriate pitch rates via starters).

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    Can I chime in on this on behalf of the OP and ask what salts would be ideal when using RO water to brew an Irish Red vs. an IPA?
    – Scott
    Commented Mar 26, 2014 at 3:45

Whether or not they're really necessary depends on the water you have and the beer you want to brew. You need to start by getting an analysis of your water. Some water districts provide all the info you need, but many of them don't. If not, an excellent resource is wardlab.com. Get test W-6. As the what the info means and how you need to adjust your water, see the water knowledge page at https://sites.google.com/site/brunwater/water-knowledge . There is also a free spreadsheet there that you can plug your water report into and figure out if and how to adjust your water. Use the color/flavor profiles, not the city profiles. Many breweries filter or otherwise change their water, so the city water profile does yo no good. In addition, you have no idea of the accuracy of the city profile.

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    It's also not uncommon for larger cities to split their water source from across more than one treatment plant, which can significantly differ. Case in point, Baltimore draws from two water treatment plants, and I have no idea which of the two it is using at any given point. They aren't entirely different, but enough to change my salt additions by several grams.
    – Scott
    Commented Mar 26, 2014 at 17:08
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    For more info on this subject, see the series of articles by Martin Brungard that's been running in Zymurgy magazine for the last 6 months. It's fascinating to see that the water from classic beer cities, like Burton on Trent, isn't necessarily the water the breweries use.
    – Denny Conn
    Commented Mar 26, 2014 at 17:54
  • Once you have the report, you can use a tool like brewersfriend.com/water-chemistry to adjust your water using your water as a base and then add additions to achieve what you want. Determining what you want will depend on what you are trying to accomplish - some try to match the water of a region for a particular style while others will adjust water to accentuate hops or malt.
    – Wyrmwood
    Commented Apr 2, 2014 at 18:22

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