Boiling hard water - what impact on bicarbonate and other ions?

[GrumpyOldGit]

Hi all,

Is there a spreadsheet or set of calculations that can tell me what happens to my water numbers if I boil the water to precip out some of the hardness?

Boiling is the only water treatment I've done so far; boil up several gallons the day before brew day, leave overnight, and then decant the water off the precipitate into a bucket and then use that water for the boil.

Based on how my water tank is being eaten alive my well delivers hard, tasty, iron-free water. Ward confirmed this (well, confirmed the hardness, just take my word on the taste):

• pH 7.6
• Sodium, Na 5
• Calcium, Ca 79
• Magnesium, Mg 32
• Total Hardness, CaCO3 331
• Sulfate, SO4-S 3
• Chloride, Cl 10
• Bicarbonate, HCO3 419
• Total Alkalinity, CaCO3 345
• Carbonate, CO3 < 1.0
• Total Iron,

Fe < 0.01
Everything else is close to zero or below detection limits.

Looking at water calculators it seems that Bicarbonate and Magnesium are the problem ions for me ('problem' in that they really skew the numbers and make any additions a problem). I'm currently extract with steeping grains for speed & convenience so mash pH isn't so much of an issue. However, at some point I want to cross to a/g so yet another reason to understand the numbers without having to send off another sample to Ward.

 

[ajdelange]

First thing we do is look at the hardness: 331/50 = 6.62 mEq/L (a lot)
Next is alkalinity: 345/50 = 6.9 (also a lot) which is a bit more than the alkalinity. As a general rule we can expect to be able to decarbonate/soften to about 1 mEq/L limited by whichever is the smaller of the two so we would expect to drop 5.62 mEq/L of each of the calcium and the alkalinity leaving 1 mEq/L hardness and 1.3 of alkalinity. We're really after the alkalinity, though so we add 0.28 mEq/L calcium before the boil bringing each to 6.9 mEq/L. You have plenty of latitude to do this as chloride an sulfate are both so low.

As both are equal now we would expect both to drop to 1 mEq/L which is only 20 mg/L calcium. While lots of beers are fine with this level of calcium may would prefer to have at least another mEq/L hardness. So why not add another mEq/L (20 mg/L Ca++) hardness before the boil. The rule of thumb says you wind ip with 1 mEq/L alkalinity if you do this but the math suggests that the alkalinity may go under 11 if there is an excess of calcium and experiment verifies that this is the case.

Remember in all this that this is a rule of thumb. Precipitation reactions are tricky to predict and it is important, therefore, that you check on the hardness and alkalinity of your treated water with drop count (or more elaborate) testing for those two parameters.

 

[GrumpyOldGit]

Thanks for the info - though I feel my brain is dribbling out my ears (though that could be the applejack, not the math). Interesting how I could increase the hardness to match the milliequivalents of solute on both and get the numbers down a bit further.

If I wanted to keep it simple - what beers would not work with a simple boil approach (no additions, just boil the day before)? I'm assuming Pilsen and other 'clean' lager types are off the menu but I'm more partial to the darker beers anyway .

On the drop count testing (drop count titration test, yes?) is there a particular kit set you'd recommend.

 

[ajdelange]

All assumptions correct.

I usually recommend the Hach kits but most people here find them too expensive.

 

[Stillraining]

First thing we do is look at the hardness: 331/50 = 6.62 mEq/L (a lot)
Next is alkalinity: 345/50 = 6.9 (also a lot) which is a bit more than the alkalinity. As a general rule we can expect to be able to decarbonate/soften to about 1 mEq/L limited by whichever is the smaller of the two so we would expect to drop 5.62 mEq/L of each of the calcium and the alkalinity leaving 1 mEq/L hardness and 1.3 of alkalinity. We're really after the alkalinity, though so we add 0.28 mEq/L calcium before the boil bringing each to 6.9 mEq/L. You have plenty of latitude to do this as chloride an sulfate are both so low.

As both are equal now we would expect both to drop to 1 mEq/L which is only 20 mg/L calcium. While lots of beers are fine with this level of calcium may would prefer to have at least another mEq/L hardness. So why not add another mEq/L (20 mg/L Ca++) hardness before the boil. The rule of thumb says you wind ip with 1 mEq/L alkalinity if you do this but the math suggests that the alkalinity may go under 11 if there is an excess of calcium and experiment verifies that this is the case.

Remember in all this that this is a rule of thumb. Precipitation reactions are tricky to predict and it is important, therefore, that you check on the hardness and alkalinity of your treated water with drop count (or more elaborate) testing for those two parameters.

Damn theres some smart people here....