Adding base to neutralize sour beer

[DaveSeattle]

I have a crazy idea: would it be possible to add a base such as calcium hydroxide (slaked lime) to a sour beer to restore it to a neutral-tasting pH? I see three uses for this: 1) Get the funky properties of lambic-type bacteria without the sourness. 2) Fix an accidentally infected beer or reduce the level of sourness in a sour beer that went too far. 3) Do something that hasn't been done before.

What say ye? Has this been done? Will it work? Will the resulting calcium ruin the beer?

A quick calculation: 20 L of beer with 1% extra acid (beyond the level we want) has about 200g of acid. Because Ca(OH)2 has two ions, we would need 100g of it. Seems like a lot of calcium to add to the beer, might wind up tasting like mineral water? But maybe that math is wrong, especially the assumption of 1% acid.

I would just try it in a pint glass but I don't have any slaked lime on hand or know where to get it locally.

 

[rschell]

Neutralizing the pH wont take the acid out of the beer, it just effects the hydronium to hydroxide ratio.

 

[ajdelange]

I have a crazy idea: would it be possible to add a base such as calcium hydroxide (slaked lime) to a sour beer to restore it to a neutral-tasting pH?

Yes, adding alkali will neutralize acids but of course the anions of the acid will still be there e.g. a Gueze with lots of lactic acid:

2HLac + Ca(OH)2 ---> 2Lac- + Ca++ + 2H20

Lactic ion has flavor at any pH but at higher pH it is less flavorfull that at lower.

I see three uses for this: 1) Get the funky properties of lambic-type bacteria without the sourness.

That would be, in my opinion, like apple pie without the cheese

2) Fix an accidentally infected beer

Were a little the tartness the only problem with infected beer that might work.

...or reduce the level of sourness in a sour beer that went too far. 3) Do something that hasn't been done before.

Try it and see!

Has this been done?

I have heard of people adjusting the pH of finished beer but always downward.

Will it work?

Only one way to find out that I can think of.

Will the resulting calcium ruin the beer?

No.

A quick calculation: 20 L of beer with 1% extra acid (beyond the level we want) has about 200g of acid. Because Ca(OH)2 has two ions, we would need 100g of it. Seems like a lot of calcium to add to the beer, might wind up tasting like mineral water? But maybe that math is wrong, especially the assumption of 1% acid.

You are trying to apply the vintner's acidity measurement which is 'as tartrate' to beer. Kolbach reported back in 1954 that the buffering of wort was about 64 mEq/pH•kg (kilogram of malt used to make it). We can guess that beer might be about the same in order to get a WAG. Twenty litres of beer might use 5 kg of malt and thus have a buffering of 320 mEq thus requiring 32 mEq equal to 5*64*∆pH*(74/2) ---> 5*64*0.1*(74/2) = 1184 mg slaked lime for each 0.1 pH shift desired. To shift 5 gal of Gueze at pH 3.8 to 4.5 would thus require about 8.3 grams. I reiterate that this is a WAG. To get the actual number you would have to titrate the beer just as the vintners do but express the results in mEq, not as tartrate.

I would just try it in a pint glass but I don't have any slaked lime on hand or know where to get it locally.

You ought to be able to get it from your LHBS. If they don't have it you can get 'pickling lime' from the the canning section of the local super market. Still no luck? You can use sodium bicarbonate but the amount required will be 84/(74/2) = 2.27 times as much and would put 1 gram sodium per gallon into the Gueze we used as an example.

 

[DaveSeattle]

Yes, to be clear, I understand that the acid will still have its own flavor, but was hoping to reduce the acidity. This could produce a funky beer without a tang. I'm with you that I like my sour beers, well, sour, but others don't including my wife, plus who knows, maybe a lambic without sourness is even better.

Your WAG is much better than mine, I didn't really apply any thought to mine at all. Ultimately it's going to be about taste, and I mostly wanted to know if I'd be in the right ballpart - if I needed to add 200 grams of calcium to get the desired effect, the beer would wind up tasting like mineral water. 8g/0.1 pH shift is still going to be rather a lot, but perhaps tolerable.

I will pick up some pickling lime next time I'm at the grocery store and see how it tastes! Didn't realize they had it there, and I wasn't planning to make a trip to the LHBS any time soon. I'll report back with results! At least results on adjusting an intended sour beer to reduce pH - I don't have any "unintentionally inoculated" batches on hand to test fixing a bad clean batch.

 

[ajdelange]

That's 8 g for an 0.7 shift (there was typo).

 

[DaveSeattle]

Oh that's excellent, I doubt l will need that big a shift in most cases and 8g of calcium should still be drinkable, though probably tastable.