I've been chatting with my local city water tech.
Based on what she sent me, the numbers work out as...

  • pH- 7.5
  • Ca- 20.1
  • Mg- 12.6
  • K- 1
  • Chloride- 5.4
  • SO4- 11.5
  • Hardness (CaCO3)- 103
  • Alkalinity(CaCO3)- 99.6
  • Bicarbonate (CaCO3)- 123.3

I guess they can all be rounded to the next higher or lower number... :)

So, my question is.. for brewing a dark beer.. I want to try Jamil's Robust Porter.. and later, an Oatmeal Stout.

  • With the high(er) Bicarb, do you boil, cool and siphon to reduce the number?
  • Or would you do an acid addition to the total water?
  • Or would you do any dilution and add salts?
  • Or build your water from RO?
  • Or do you do nothing?
  • Given any choice.. what YOU would do.. THEN what would you add as salts for that water for the dark beer?

If you simply built your water from RO, what would you add for 5g of all-grain? Or, if you simply added "x" ml of Phosphoric or Lactic Acid.. what would you then do.

Thanks for any help.


  • I would do whatever the "brown malty" or "brown balanced" profile on Bru'nwater told me to do. sites.google.com/site/brunwater
    – Denny Conn
    Feb 22, 2015 at 17:26
  • Thanks, that's part of my question. i.e., OR do you do nothing? So, if that is the best option for this Porter/Stout.. based on my water, should I add any salts to enhance the maltiness (rather than the happiness as for an IPA) ?
    – SRBill
    Feb 23, 2015 at 0:50
  • You can always do nothing. I made award winning beers for years before I dove into water treatment. Or you can download Bru'nwater and plug your profile into it, then see what it suggests doing.
    – Denny Conn
    Feb 25, 2015 at 19:36

3 Answers 3


I would leave this alone (mostly).

  • There are no red-flags in the water report.
  • Bicarbonate and alkalinity are moderately well suited for a stout.

If you want to tip the sulfate / chloride ratio toward malty you only need 1.5 to 2 grams of CaCl to do it. (Do you have a scale sensitive enough?) Put this in at the beginning of the boil.


Why do you want to balance the Bicarbonate? Most things I've read say that a very alkaline water is great for darker beers. Here's one source (of many):


  • Sorry, I should have said alkalinity.. not bicarb.
    – SRBill
    Feb 23, 2015 at 14:41

Firstly I am assuming that the figures you give are metric (which they probably aren't) ie mg per litre and so you will have to convert if not. secondly the target water profile is just a suggestion, the formulae allow you to get to any profile you decide to use.

General target water profile for stout: Ca100 bicarbonate 100-200 cl 300 so4 100.

therefore. for sulphate we use Target - actual x volume/0.56/100. so assuming a brew length of 25 litres. 100-11.5 x 25/0.56/1000 = 3.9 grams CaSO42H2O to be added (note 0.56 because CaSO42H2O contains 56% Sulphate and 23% calcium) same equation for chloride 300-5.4 x 25/0.64/1000 =11.5 grams CaCL2 for the calcium we have to add the calcium in the two additions above to the calcium present in the water and then see if this is sufficient, or if more is needed. So target(300)-Actual(20) x volume (25)/1000 = 7grams required from Calcium Sulphate addition 3.9gx0.23 =0.69grams from calcium Chloride addition 11.5g x 0.36= 4.14 grams. SO 7-(4.14+0.69)=4.83 calcium still required. so using the formula you add the required amount via the Calcium sulphate or calcium chloride. (for stout 1 would use both to keep them roughly in the proportion of 3:1 Chloride Sulphate)

if you had to adjust the alkalinity you would use the formula.

(actual -taget x volume/Alkalinity factor of the acid used ie 185 for Brewpac CRS) =mls of CRS/lactic/etc acid to be added.

Hope this is helpful rather than just more confusing

  • Thanks Frank.. I think I understand how you did the numbers. I'll copy it to my editor and save it as a file. For Alkalinity, would you suggest lowering it? I used a few ml of lactic the last time I brewed a stout rather than boiling/decanting.. and tasted a tiny bit of sourness. That may have been due to something that didn't get well cleaned though.
    – SRBill
    Feb 23, 2015 at 14:43
  • Where did you get those target numbers?
    – Denny Conn
    Feb 23, 2015 at 16:29
  • SRBill From my understanding I would say your Alkalinity(bicarbonate) is within range.
    – frank
    Feb 23, 2015 at 19:50
  • Denny Conn the target numbers are those supplied by Brewlabs in the UK. I don't claim them to be the ones you must use, but just to illustrate how the formulae should be applied when you decide which profile you are aiming for.
    – frank
    Feb 23, 2015 at 19:58

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