Water Treatment for Brewing 3: Adjusting the Water

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

I’ve already gone through why you should adjust your water in part one of this mini-series, and how to get your water’s baseline in part two.  Here, I’ll finally get to the meat of the matter, actually adjusting the water.

What you don’t want to do is to go out and get those pre-measured salt packets (to Burtonize, for example) and just dump it in your water.  This, on top of whatever is already in your water, will just be overkill.  These salt packets are really only useful when starting from RO or distilled water.  What you’ll really need are at least some of the following compounds from a homebrew shop or grocery store pharmacy (just make sure its food grade).  Listed are the contributions in parts per million (ppm) of each compound per gram added per gallon (and per liter in parenthesis) of water you wish to treat.  In other words, if you want to treat a single gallon of water and you add one gram of listed compound, you will get the listed addition.  I typically only use calcium sulfate, calcium chloride, and lactic acid.

  • Gypsum aka Calcium Sulfate, CaSO4: 61.4 (232.4) ppm Ca, 147.5 (558.3) ppm SO4; great for enhancing hop bitterness and adding calcium
  • Calcium Chloride aka CaCl2: 71.9 ppm (272.2) Ca, 127.5 (482.6) ppm Cl; great for enhancing maltyness and adding calcium
  • Chalk aka Calcium Carbonate, CaCO3: 105.7 (400.1) ppm Ca, 322.3 (1220) ppm CO3; limited usefulness because chalk does not dissolve well in water (about 1 gram per 5 gallons max or less- see part 3.5 for limits and a trick to increase it), but good when used in small amounts to add Ca and alkalinity
  • Baking Soda aka Sodium Carbonate, NaHCO3: 72.3 (273.7) ppm Na, 191.9 (726.4) ppm CO3; good for adding alkalinity, but limited usefulness because it also adds sodium
  • Pickling/Slaking Lime aka Calcium Hydroxide, Ca(OH)2: 142.8 (540.6) ppm Ca, 434.8 (1646) ppm (OH); great for adding alkalinity and Ca, but it can be dangerous to work with; only add to the mash directly to avoid a dramatic pH increase
  • Epsom Salt aka Magnesium Sulfate, MgSO4: 26.1 (98.8) ppm Mg, 103 (389.9) ppm SO4; not very useful because Mg should be kept low
  • Table Salt aka Sodium Chloride, NaCl: 104 (393.7) ppm Na, 160.3 (606.8) ppm Cl; use only non-iodized; not very useful because of added sodium
  • Magnesium Chloride aka MgCl2: 31.6 (117) ppm Mg, 92.2 (349) ppm Cl; not very useful because Mg should be kept low
  • Lactic Acid aka C3H6O3: used to reduce alkalinity, and therefore residual alkalinity (RA), by 100 ppm per 0.64 mL acid per gallon (0.17 mL per liter) at the common strength of 88%; 88% lactic acid has a specific gravity of 1.21 (1.21 g per mL); taste threshold 300-400 ppm minimum (for some people much more): translates to 1.1-1.4 mL per gallon (0.28-0.38 mL per liter) of 88% lactic acid
Lactic acid and brewing salts

Lactic acid and brewing salts: gypsum, calcium carbonate, calcium chloride, pickling lime, and baking soda

You’ll want to treat all of your brewing water, mash and sparge included.  If you are going to use acid to adjust the RA and therefore pH, you should add it separately to the mash and sparge water, as they have different RA requirements.  Sparge water needs less RA because the initial mash water will already have neutralized much of the acid potential of the malt.  You should not add anything to boost alkalinity in the sparge water (lime, baking soda, chalk) for this reason.  So, lets go through a quick example.  You’ll want to put priority on:

  1. getting your sulfate and chloride ratio correct
  2. increasing calcium levels to 50-150 ppm
  3. getting your RA (and thus resulting pH) to an appropriate level.

Beyond that, just make sure nothing is too out of whack.  Don’t stress out too much over getting everything perfect- all of this is just an approximation anyways (and yes, that’s coming from an equation loving engineer, so really, RDWHAHB).  So, lets say your water report breaks down like this (in ppm):

Calcium: 0.5
Magnesium: 0.3
Sodium: 80
Iron: 0
Bicarbonate: 80
Sulfate: 10
Chloride: 70

The first thing to notice is that the calcium is very low, so we’ll want to get that up by using CaCl and CaSO4 when we correct our SO4/Cl ratio.  Secondly, the sodium is pretty high.  Its not so high that we need to worry about it (say, above 100-150 ppm), but it does mean we need to stay away from anything with sodium when adjusting other ions, which limits our choices, especially when adjusting RA.  And, the iron level is good to go (though you probably already know that by tasting your water).

Lets now look at the sulfate to chloride ratio; this is where style comes into play.  Right now its 10/70, or about 0.14.  This is not an ideal range for any beer style (see part one of this mini-series).  Lets say we want to adjust it for a beer balanced in its hop and malt character.  For this, we want a ratio of about 1.3, so we’ll want to bring up the sulfate concentration with CaSO4.  To figure out how much, we solve:
ratio = (current SO4+added SO4)/(current Cl+added Cl)
=> 1.3=(10+x)/(70+0)
=> x=1.3*70-10
=> x=81 ppm SO4.
To get 81 ppm SO4, we need 81/147.5=0.55 g per gallon CaSO4 (147.5 being the gram per gallon contribution listed above), or 81/558.3=0.145 g per liter.  This will also contribute 0.55*61.4=33.8 ppm Ca (or 0.145*232.4=33.7 ppm Ca in metric, nominally the same value but for the rounding error), bringing us to 34.3 ppm Ca from our baseline 0.5.  This is a little low from the 50-150 ppm we want, so now we need to look at what other ways we can get Ca in the water.

Our first option, and generally the simplest, is to just increase both SO4 and Cl in a constant ratio of 1.3 using CaSO4 and CaCl2.  You’ll have to play with the numbers a little doing an iterative process with similar math to above (or you can set up a system of equations if you’re up to it, but why bother?).  This is where the mineral addition spreadsheets and online calculators really come in handy.  In any event, one solution is to add 0.7 g/gallon (0.185 g/L) CaSO4 and 0.15 g/gallon (0.040 g/L) CaCl2, yielding 54.3 ppm Ca, 113.2 ppm SO4, 89.1 ppm Cl, and a SO4/Cl ratio of 1.3.  This is a great option as long as you don’t over do it.  Though the ratio of SO4/Cl is the most important factor, adding too much of them, even in the proper ratio, can lead to a mineral taste, especially in pale beers.  In general, you want more of both SO4 and Cl for darker beers and less for pale beers for any given ratio.  I believe John Palmer once made the analogy of two toddlers on a see-saw compared to two gorillas.  They will both balance where you want (same ratio) but the gorillas pack a lot more wallop.

So, if you’re nervous about too much Cl and SO4 and you still don’t have enough Ca, you’re left with chalk or lime.  Neither is a great option because of their listed limitations and they both contribute alkalinity, which may or may not be good for your beer.  Lactic acid can be used to some extent to re-balance against this extra alkalinity if needed.

Lets take a look at alkalinity.  Adding Ca (or Mg) decreases the RA, (recall the equation from part one).  If you are brewing a paler beer, this is probably a good thing.  If you are brewing a darker beer however, you’ll want a higher RA to buffer against the additional acidity of the dark malt.  Its difficult to say exactly what RA you want for a given color; really what you are looking for is a mash pH between 5.2 and 5.8.  Most calculators will provide good estimates of the RA you want for a given color in SRM.  Perhaps this could be a part four of this series.

In any event, if you want to decrease the RA, you can add more Ca or Mg as discussed in part one.  Keep your SO4 to Cl ratio the same as above.  However, for a pale beer, it can be detrimental to just keep adding these compounds.

Another option is to use acid, most commonly lactic.  Lactic is used because it will only change alkalinity, unlike some other acids like phosphoric which can react with Ca (and thus further changing RA- it starts getting a bit complicated to keep track of everything at that point), or add sulfate (sulfuric acid).  However, it should only be used in quantities of about 1 mL/gal (0.26 mL/L) or less to avoid a tangy off flavor.  Some people are far more sensitive to this flavor than others, something to keep in mind if entering a competition.  0.64 mL lactic acid per gallon (0.17 mL per liter), at the common strength of 88%, will decrease RA by 100 ppm without affecting other ions, so its doubtful you’ll ever get close to the flavor threshold.

Increasing alkalinity  can be a bit trickier, especially for water this high in sodium.  That’s because you won’t be able to use much or any baking soda, which is very effective at raising alkalinity, but also sodium.  Calcium carbonate would be perfect for soft water- it would raise alkalinity and calcium.  But, it also has very low solubility in water, limiting its usefulness.  Running down our list, that leaves the pickling (aka slaking) lime.  Lime works great, but it has the downside of being caustic.  Be careful when handling, and add only to the mash.

So, that’s all for now.  RA is perhaps a post (and much more) onto itself, and maybe one day I’ll get along to writing one.  For now, I’d love to hear any questions or comments and do a follow-up Q&A post(s).  In part 3.5, I talk about some of the solubility limits of the various ions in water, and in part 3.6 I present some weight to volume conversions for the various salts so you can measure them by teaspoons or milliliters.

[2014.03.26 UPDATE: I have started adding all calcium additions normally for the sparge water directly to the kettle instead, an idea I got from Palmer and Kaminski’s Water.  This will help ensure a proper level of calcium in the boil and for fermentation.  For the few batches I have used this technique so far, the yeast seems to flocculate much faster after a nice healthy fermentation.]

Read on in part four for some Lessons Learned >>>

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

– Dennis
Life, Fermented


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

One Response to Water Treatment for Brewing 3: Adjusting the Water

  1. Dennis says:

    UPDATE 2013.08.26: I am trying to be better about presenting information in both imperial and metric, so everything in this post should now be listed in both systems. Let me know if I missed any here or elsewhere, or if there is a more useful way to display the metric values (instead of per liter).

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