Boiling water to reduce Alkalinity?

I have a Ward report on my water and it is as follows:

Na: 24 ppm
Ca: 60 ppm
Mg: 39 ppm
Sulfate (SO4-s): 15 on the report = 45 for brewing use
Cl: 21ppm
Bicarbonate: HCO3 333
Total Alkalinity CaCO3: 273
Total Hardness CaCO3: 313
pH: 7.8

I am brewing up a Belgian Golden ale, 12 gallons, with 27 lbs of grain and 5% of the grist is acid malt. This will be a sour beer base.

Now I am looking at Kaisers Water Calculator and using the advanced sheet i entered in my values above, and will be boiling the water the night before and letting the solids precipitate (correct wording?) out and siphon of the water. The calculator shows that the TA will go from 273 to -193. Also if I cut this water down with 50% RO the TA then goes to -255 and cuts the above minerals in half. The estimated pH is 5.2. I will add a couple of grams of CaCL, and some CaSO4 to the mix.

My question is, does anyone out there have any experience with this and how accurate is the new TA number? If the brew was further out I would boil a sample and send it to Ward for another analysis.

Also am I on the right track??

thanks in advance

Follow up question:

What negative effects will the untreated Total Alkalinity have upon a Golden Ale? recipe is 85% 2 row, 5% each of Acid, Vienna, and wheat malts. Estimate SRM from beersmith is 4.4.

since the grist is "heavy" on the acid malt (5%) it seems like the calculators put this right in the 5.4 range, (this will be verified with a pH meter on brew day). Would adding back some CaCL be a good thing??

Total Alkalinity cannot go negative. Residual Alkalinity can go negative. When boiling and decanting, about the lowest you can reduce the bicarbonate concentration to is 55 to 60 ppm. That's about 45 to 50 ppm alkalinity as CaCO3. That is also the resulting Total Alkalinity.

Assuming that the negative value you mention is actually RA, then the need to include acid malt in the grist is quite debatable. If you have pH measurement capability, I'd leave it out initially and only add it if the mash pH failed to drop below 5.5.

It is impossible to have total alkalinity go below zero by boiling water hard/carbonaceous or not. If one adds acid to the water until the pH reaches 4.3, then 50 times the number of milliequivalents of acid required per liter of water is the alkalinity. Thus for your water with alkalinity 273 it would require 253/50 = 5.06 mEq acid per liter. Negative alkalinity is achieved when one continues to add acid at this point. For -193 you would add 193/50 = 3.86 mEq additional (per liter).

What actually happens when hard carbonaceous water is boiled is pretty much anyone's guess. If you plan to use this technique as a matter of course I would definitely invest in a hardness test kit of the type that gives calcium and total or magnesium and total hardness and an alkalinity test kit (www.hach.com) so that you will know what really happens. A rule of thumb is that alkalinity or hardness, whichever is limiting, can be taken down to about 1 mEq/L (50 ppm as CaCO3). Assuming this to be the case and taking calcium down to about 1 mEq/L would drop about half the alkalinity so you would have alkalinity of about 130, calcium at about 19.3 mg/L and Mg at about 28. RA would be 100 down from 212. If diluted 1 + 1 with RO water alkalinity drops to 65, calcium to 9.6, magnesium to 14 and RA to 50.

Are you perhaps confusing total alkalinity (TA) and residual alkalinity (RA)?

ajdelange said:

It is impossible to have total alkalinity go below zero by boiling water hard/carbonaceous or not. If one adds acid to the water until the pH reaches 4.3, then 50 times the number of milliequivalents of acid required per liter of water is the alkalinity. Thus for your water with alkalinity 273 it would require 253/50 = 5.06 mEq acid per liter. Negative alkalinity is achieved when one continues to add acid at this point. For -193 you would add 193/50 = 3.86 mEq additional (per liter).

What actually happens when hard carbonaceous water is boiled is pretty much anyone's guess. If you plan to use this technique as a matter of course I would definitely invest in a hardness test kit of the type that gives calcium and total or magnesium and total hardness and an alkalinity test kit (www.hach.com) so that you will know what really happens. A rule of thumb is that alkalinity or hardness, whichever is limiting, can be taken down to about 1 mEq/L (50 ppm as CaCO3). Assuming this to be the case and taking calcium down to about 1 mEq/L would drop about half the alkalinity so you would have alkalinity of about 130, calcium at about 19.3 mg/L and Mg at about 28. RA would be 100 down from 212. If diluted 1 + 1 with RO water alkalinity drops to 65, calcium to 9.6, magnesium to 14 and RA to 50.

Are you perhaps confusing total alkalinity (TA) and residual alkalinity (RA)?

Click to expand...

Looking back at the worksheet, yes it was RA as CaCO3.

So would boiling the water be a good solution, or just take the water and split it with 50/50 RO?

The easy way out is to dilute 9+1 or so with RO water. This would lower your alkalinity to 29 and your hardness to 31. RA would be slightly positive at 23 ppm as CaCO3 but the alkalinity has been reduced more than you can reduce it by boiling. OTOH if you boil and drop some alkalinity that way you can use less RO water in a post boil dilution. The problem with the boiling is that you really need another water analysis to tell you what the post boil mineral content is and that's the real advantage of the RO method. You don't need another analysis. But you do have to pay for and lug RO water from the store to your brewery or shell out for an RO unit to be installed in your brewery.