Decarbonating water with lime questions

[John Meerse]

I’m planning on following A.J. deLange’s method for using slaked lime to decarbonate my water, as outlined in the Water book by Palmer and Kaminski. I’ve run through the process a couple times with small amounts of water (1 pint and 3 quarts) and feel confident I understand the process. I’m going to brew this Sunday, and so will treat my water on Saturday to allow time for precipitation to occur.

I have 2 questions: If I need 9 gallons for my mash water, how much should I treat, since I’ll be leaving some behind with the precipitate in it?

Do I need to also treat my sparge water, or is it sufficient to just treat my strike water?

I’ve been using lactic acid to neutralize the alkalinity, but I think I’m getting off flavors in the finished beer (typically about 1.25 tablespoons). I don’t have phosphoric acid, and I believe the amount of acid malt I’d need would go over the recommended limit. I don’t have access to RO water, and really don’t want to buy that much distilled water and have to recycle all those jugs.

Thanks very much!

 

[bierhaus15]

What is your starting alkalinity? I used lime softening to treat my very hard well water last year and had mixed success. I was adjusting the pH to around 12 and lost maybe 10-15% of the total water to precipitate, although I was also seeing significant Mg apatite formation and trying to remove that as well. If I were to do this again, I would not take the pH up that high.

One thing I noticed is that I really needed more time for the chalk to drop out of solution and fully settle. Maybe the lower pH treatment would reduce this settling time, but it was much easier when I'd treat the water on Friday and give it until Saturday evening to fully settle/decant. That said, I would treat both your mash and sparge water if possible.

 

[John Meerse]

Here’s the water report I’ve been using, from early 2018. I have well water. With these numbers, Brewer’s Friend advanced water calculator has been pretty reliable for paler ales.

When I did my test runs of the slaked lime method, I kept the pH in the 10’s and it was clear the next day.

 

[mabrungard]

Raising pH above 11 with that water isn't going to provide an improvement in the end product. The only thing that the higher pH will do for you, is speed the reaction. Your water has low magnesium and it cannot be reduced any more with lime softening. The calcium precipitation reaction occurs when the water pH is brought above 10. Raising the pH farther just means that you'll have more neutralization to do to bring the treated water pH down to a suitable range.

Regarding neutralization, if your just treating a small batch of water, pouring it back and forth between 2 buckets will help get CO2 into the water and it will neutralize some of the high pH. That reduces the amount of acidification that might subsequently be needed. Bubbling air through the water is another way to do the same thing.

 

[ajdelange]

I'm flattered that you refer to this as A.J.'s method but be aware that it has been in use for hundreds of years.

I also think we should mention Hubert Hanghoffer who pointed out to me that the process is really one of raising pH with lime and then neutralizing that lime with bicarbonate ion until pH 8.3 is reached at which point the solution should be close to equilibrium with the air and at about 1 mEq/L each of hardness and alkalinity.

Also note that one virtually must check hardness and alkalinity after processing in order to see what is actually realized.

And to answer the question asked: yes, process the sparge water too. Alkalinity in sparge water will raise the pH of the wort just as alkalinity in the mash will raise its pH.

 

[John Meerse]

Thanks very much for your replies. I did my treatment this morning with 11 gallons water, anticipating about 1 gallon loss when I decant the water tomorrow. I added a bit over 2 tsp chalk, stirred well to suspend it, and then mixed 5.7g slaked lime with 150 ml water into a slurry. I started with adding half the lime slurry which brought the pH to 9.6, then added small amounts until the pH rose to 10.1. The water is now sitting in my garage, and I plan on decanting tomorrow morning if it seems clear.

I don’t currently have a way to test for hardness and alkalinity other than test strips I use in my pool, which give very broad ranges. Once I’ve decanted the water, is it reasonable to treat it similar to the methods described in the Brewing Water Chemistry Primer sticky?

Thanks again,
John

 

[John Meerse]

After letting the water sit for about 23 hours, the water is generally clear, pH is 9.77, alkalinity between 0 and 40, and total hardness between 0 and 100. Some small white “floaties” were on the surface, which dissolved when I gave a gentle stir.

Am I good to go, or should I wait for the pH to drop to the above mentioned 8.3?

 

[mabrungard]

You need to decant off of the sediment, as soon as the water has cleared. That re-solution of CO2 that I mentioned, is working against you when the sediment is present.

Assuming that your observation above is with the decanted water, the pH would eventually drop to the 8.3 range. But most would try and speed the process with some sort of aeration or acidification.

 

[John Meerse]

Excellent, thanks Martin!

 

[ajdelange]

There is no need to rush. The carbonic acid being added from the atmosphere is coming in very slowly. It is adding acid and thus reducing the alkalinity of the water much faster than the precipitated carbonate will re dissolve. You certainly do not want to wait for the pH to lower to 8.3 as you will be waiting till Michaelmas (or longer). Hubert Hanghoffer recommends bringing the pH to 8.3 with the very accessible acid source: the bicarbonate ion in your water. Just add more tap water until pH 8.3 is reached. This, of course, assumes that your tap water's pH is less than 8.3 by a substantial amount.

Probably the easiest thing to do is take the water a pH 9.77 and add some lactic or phosphoric acid to it in sufficient quantity to reduce the pH to the desired mash pH. You can then treat your water as if it had 0 alkalinity in any calculations you do for acid addition for mash pH control.

 

[John Meerse]

I decanted about 9.5 gallons for my strike water and added about 2 tsp each of gypsum and calcium chloride. With 8oz of acidulated malt (grain bill was 16.5# 2-row, 7# malted rye, and 8oz c-60), I hit a mash pH of 5.41. Very pleased!