Author Topic: How much lactic acid or acid malt is too much?  (Read 3162 times)

Offline jklinck

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How much lactic acid or acid malt is too much?
« on: February 08, 2011, 02:16:54 AM »
I've been using the EZ water calculator for a while and noticed that it has recently been updated to include an estimated mash pH. After inputing some beers I've made in the past it showed a higher than desirable pH. So I've been adjusting the calculations with lactic acid additions. At first I tried adjusting the pH by adding more gypsum, CaCl or espom salt but adding 1g  only changed the pH by about 0.01. On my next beer the calculation said I should add 4 mL of lactic acid to the mash or 6oz of acid malt. This seems high to me but I don't have much experience with lactic acid or acid malt. So how much is too much?
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Offline tomsawyer

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Re: How much lactic acid or acid malt is too much?
« Reply #1 on: February 08, 2011, 04:30:32 AM »
I've read that the threshold for tasting 88% lactic acid is 2ml per gallon.  That was attributed to Palmer, I forget the source now.  Other folks have recommended no more than 5ml in a 5gal batch.  In any case I've never needed to add that much to get my water pH right, although I do utilize my flavor additions (CaCl2 and CaSO4) in the msh to help get the pH down as well.  Sounds like you are OK with your addition, assuming it was for 5gal.  You can always add a little distilled water to your water to reduce the amount of pH adjustment needed.  I'm not sure if preboiling would reduce the alkalinity, it might.

I'm not so familiar with sauermalz, someone else can comment on that.
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Re: How much lactic acid or acid malt is too much?
« Reply #2 on: February 08, 2011, 07:43:59 AM »
To lower the pH of 1 lb of grist by 0.1 pH units you need about 4.1g of acid malt or 0.11 ml of 88% lactic acid. Its 9g acid malt and 0.25 ml 88% lactic acid for 1 kg of malt.

Acid malt is pilsner malt that was sprayed with lacto fermented wort before it was dried again. It contains about 3% lactic acid by weight and is an elegant way of adding acid to your mash since you can weigh it when you weigh the other malts and you don't have to mess with measuring the liquid stuff.

I'm comfortable recommending up to 4% acid malt in the grist. This is equal to ~ 1.1 ml 88% lactic acid for every kg of grist (0.5 ml for every lb). But I haven't done any taste testing to find the limit. When using lactic acid for light beers and highly alkaline water, it is a good idea to reduce the water alkalinity with other means first (dilution, slaked lime, boiling) before using lactic acid to get the pH down further.

1.1 ml for every kg of grist comes out to about 5 ml in an 5 gal batch. I'm not sure if it is better to recommend the acid amount based on the gist size or batch volume. I have started to favor the grist size since it provides the main pH buffer in mashing and higher gravity beers should be able to stand up to more lactic acid additions than lower gravity beers.

Kai
« Last Edit: February 08, 2011, 12:57:17 PM by Kaiser »

Offline tomsawyer

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Re: How much lactic acid or acid malt is too much?
« Reply #3 on: February 08, 2011, 07:57:49 AM »
I'd go by volume since we're worried about a threshold concentration causing an off flavor.  While a bigger beer might mask a more pronounced flavor, I don't know that we can count on it.
Lennie
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Re: How much lactic acid or acid malt is too much?
« Reply #4 on: February 08, 2011, 01:04:01 PM »
Lennie,

I made this comment because the amount of lactic acid depends more on the amount of malt than the amount of water or beer produced.

For example. If you make a 12P Pils that uses 4kg Pilsner malt for a 5 gal batch you’ll need about 3 ml lactic acid to get the mash pH from 5.75 to 5.45. This assumes water with zero residual alkalinity. If you are making an imperial Pilsner that uses 8kg of malt for the same amount of beer I would expect that you need 6 ml lactic acid to get from 5.75 to 5.45. So the question is, does the stronger flavor of the larger beer allow for a higher lactic acid threshold or should be limit the lactic acid addition to 5 ml and accept the slightly higher pH?

Kai