Water Treatment for Brewing 1: The Basics

[Miniseries Part One, Two, Three, Three-point-Five, Three-point-Six, Four]

This is the first post I am doing on water treatment, and not the last.  By water treatment, I mean adding various salts or acids to the water to make it more suitable for various styles.  These salts dissociate into ions (charged particles) in the water which can affect yeast health, flavor perception, mash efficiency, boil protein coagulation, etc.  But, beer has been brewed for thousands of years without anyone knowing what an ion is, and I am sure most of you are already making great beer, so why should you care?  Water treatment will allow you to bring your beer from “I’d definitely buy some of that” to award winning.  Think about a meal that you have had that didn’t have nearly enough salt in it.  Chances are it was dull and lifeless- the flavors there, but muted and muddled.  Add a little salt, and suddenly the flavors come alive and pop, making the rest of the effort to prepare the meal suddenly much more worthwhile.

Lets be clear- it won’t bring your beer from “meh” to good, only great to even better.  Frequently its a little missing something you just can’t put your finger on.  Someone looking to treat their water (beyond carbon filtering and getting chlorine out), should have their fermentation and other practices locked down first.

First, some of the important ions by name and (chemical symbol).  Superscripts denote the ion’s electrical charge and subscripts denote how many of a certain atom is present.

  • Calcium (Ca2+): Useful for mash efficiency, yeast health, and protein coagulation during the boil.  Should be present in concentrations of at least 50 parts per million, or ppm (ppm is about equivalent to mg/L), up to 150 ppm or so.
  • Magnesium (Mg2+): A very small amount is required for the mash enzymes, but there is plenty in the grain or DME itself for this purpose.
  • Sodium (Na+): At moderate concentrations (under 150 ppm), it can make the beer seem “rounder” but can start to clash with sulfate if either is in a high concentration.  Generally, it is easiest to just keep this as low as possible.
  • Sulfate (SO42-): Accentuates the hop flavor, lending crispness and dryness to the beer.  Desired concentration depends on style.
  • Chloride (Cl): Accentuates maltyness and beer fullness.  Desired concentration depends on style.  Not to be confused with chlorine (Cl2).

Most of the ions listed are pretty self explanatory- keep them in the listed concentration and you are good to go; bigger beers tend to need a bit more of everything.  Sulfate and chloride are a little trickier.  If your beer is hoppy, you’ll want a higher sulfate concentration; if its malty, you’ll want more chloride.  There are “ideal” ranges for various styles, but the most important thing is actually the ratio of the two, not necessarily the exact values (though ideally you want lower concentrations of both for lighter or more delicate beers).  For an extremely bitter beer, you’ll want a ratio of sulfate/chloride of over two, up to about 2.3.  Bitter beers should be closer to 2, balanced about 1.3, malty around 0.75, and very malty about 0.5.  You’ll probably want to avoid anything far outside of these ranges- when sulfate is too high, the bitterness can seem very harsh and sharp; when chloride is too high, you can get something akin to a metallic salty or bitter taste.  Even without venturing outside of the “maximum” range, going too high even for a particular style can result in these off-flavors.

ions in water

Water molecules surrounding the charged ions of a brewing salt.  The positive side of the water (red) attracts to the negative ion (green), and the negative side (blue) attracts to the positive ion (yellow).

One last concept for now: alkalinity. It is generally expressed as carbonates or units of carbonate equivalents in ppm.  There is much to cover on this topic (it, and its interplay with mash chemistry is extremely complex), but as far as is immediately important for brewing, alkalinity is a measure of the water’s ability to buffer.  As anyone knows, if you put vinegar and baking soda together, they react and neutralize.  And it makes a hell of a volcano with a little red food coloring.  This is a similar concept, but in this case the alkalinity is a “weak” base.  It won’t make the water more basic once it reaches a certain pH level, but if you add an acid it will react to neutralize the acid until it reaches that equilibrium pH again.  This is the idea behind Five Star’s product 5.2 Stabilizer, an assortment of buffer compounds.

You’re not going around throwing vinegar in your beer (I hope).  But, malts, especially dark malts, will acidify the mash.  The alkalinity will buffer against this, and the mash pH will more or less stay in a reasonable range (grain wants to be beer!).  That is, unless there is enough dark malt to overwhelm the alkalinity, at which point the mash pH can fall far enough to affect enzymatic activity, and even produce a tart or sharp beer.

To further complicate matters, certain compounds such as calcium and magnesium will react with others in the malts to form acids to reduce the alkalinity beyond what the malt will do alone.  Thus, the concept of residual alkalinity (RA): alkalinity that is left over after the calcium and magnesium compounds have their way with the buffer compounds as such:
RA=Alkalinity - [\frac{Calcium}{3.5}+\frac{Magnesium}{7}].

The upshot of all of this is that you’ll want a higher RA for darker beers.  Really what you are controlling indirectly is the mash pH.  Unfortunately, roast malts tend to affect pH more than crystal malts even for an equivalent color (most of the time…), so there isn’t a perfect relationship between beer color and desired RA.  You also don’t want an RA that is too high for a given style, as this can result in harsher bitterness, a very dull beer, and a myriad of other subtle problems, including how your tongue senses the flavor compounds in the beer.  RA affects not only the mash pH, but the pH of the fermentation and the final beer, so it is important to get it right initially.

In part two of this miniseries I will talk about how to read your water report, and part three will discuss how to treat your brewing water.  I also highly suggest a multi-part “water-ganza” podcast series on Brew Strong with Jamil Zainasheff and John Palmer (part one, two, three, four and a new episode).

For help with brewing calculations, I recommend a free downloadable spreadsheet called Bru’n Water.  There are also other calculators like this available, like John Palmer’s (near the end of this page) or Kai Troester’s over at Brewer’s Friend.  Each will result in slightly different recommendations.

Click here to read on with part two >>

[Miniseries Part One, Two, Three, Three-point-Five, Three-point-Six, Four]

– Dennis
Life, Fermented

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About Dennis
Home brewer, home chef, garage tinkerer. Author of Life Fermented blog.

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