Author Topic: Lactic acid and ph adjustment  (Read 3359 times)

Offline rbowers

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Lactic acid and ph adjustment
« on: August 09, 2015, 02:52:26 PM »
Going to brew my first Berliner weisse today and had a question about using lactic acid to adjust pH.  I will be souring the wort with L. Brevis for 4-5 days and boiling again prior to adding the primary yeast.  From what I've read, it seems to be suggested that the pH of the wort is lowered to 4.5 or so prior to adding lactobacillus to facilitate its growth as well as prevent other nasty bacteria from taking hold before the pH can be lowered by lacto. 

Is there any way to calculate how much lactic acid (88% strength) to add to ~11 gallons of wort to get the pH down around 4.5?  I guess I don't know my starting pH yet (assume 5.3-5.5 maybe???) which I'm sure affects the answer.  Just looking for additional advice.  Is this just kind of a "test and see" type thing?  What's a good increment to start with?

Offline quattlebaum

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Re: Lactic acid and ph adjustment
« Reply #1 on: August 09, 2015, 03:32:05 PM »
i am on day 5 now of the exact same process except with  L. buchneri/wyeast 5535.  i used 100%RO and mash PH at 5.4 room temp then added 88% lactic till reached 4.8PH then boiled 15min racked to carboy while flushing with co2 and have been keeping temp at 100 to 110F. i just kept adding acid and checking but got lazy and just left it at 4.8PH. It dropped to 4.1PH in 12hrs.It has only dropped to 3.67PH currently and i am becoming impatient:)  mine was 6 gallons of wort and hell  i added  5 ML to get it to 4.8. 

Offline ynotbrusum

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Re: Lactic acid and ph adjustment
« Reply #2 on: August 09, 2015, 08:41:46 PM »
I just used Beersmith and calculated the mash pH, then added lactic acid additions in the mash profile to get to 4.5.  Then after completing the mash, I ran it off then added the extra lactic acid.  It reduced it to 4.3, so it wasn't exactly the same as adding it to the mash, but it was close.  I soured with Omega Labs Lacto blend of Brevis and Plantarum (a 5 day starter) and it went to 2.9 in 16 hours.  Really sour.
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Offline klickitat jim

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Re: Lactic acid and ph adjustment
« Reply #3 on: August 09, 2015, 10:16:40 PM »
Going to brew my first Berliner weisse today and had a question about using lactic acid to adjust pH.  I will be souring the wort with L. Brevis for 4-5 days and boiling again prior to adding the primary yeast.  From what I've read, it seems to be suggested that the pH of the wort is lowered to 4.5 or so prior to adding lactobacillus to facilitate its growth as well as prevent other nasty bacteria from taking hold before the pH can be lowered by lacto. 

Is there any way to calculate how much lactic acid (88% strength) to add to ~11 gallons of wort to get the pH down around 4.5?  I guess I don't know my starting pH yet (assume 5.3-5.5 maybe???) which I'm sure affects the answer.  Just looking for additional advice.  Is this just kind of a "test and see" type thing?  What's a good increment to start with?
Wild guess, 30ml.

My last brew day I did a sour blonde, ~7 gallons. It finished the boil at 5.0 and I added 15ml lactic 88%, which dropped it to 4.5 ph. So I would start with 30ml, and see where its at. Add more if needed.

I don't know about it helping the lacto but it ought to help keep other bugs in check. Some folks will tell you not to bother because the other bugs add complexity, and thats fine. I happen to like a cleaner more precise sour so I'm trying this technique.
« Last Edit: August 09, 2015, 10:46:59 PM by klickitat jim »

Offline johnnyb

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Re: Lactic acid and ph adjustment
« Reply #4 on: August 10, 2015, 02:09:26 PM »
I just used Beersmith and calculated the mash pH, then added lactic acid additions in the mash profile to get to 4.5.  Then after completing the mash, I ran it off then added the extra lactic acid.  It reduced it to 4.3, so it wasn't exactly the same as adding it to the mash, but it was close.  I soured with Omega Labs Lacto blend of Brevis and Plantarum (a 5 day starter) and it went to 2.9 in 16 hours.  Really sour.

I didn't even bother bringing the wort pH down with lactic acid when using the Omega Labs blend. Just pitched it at pH 5.3 and it still brought it to 3.1 in less than 24 hours. I think it's fast enough to eliminate any worries about infection before it takes hold and drives the pH down on its own.


Offline ynotbrusum

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Re: Lactic acid and ph adjustment
« Reply #5 on: August 11, 2015, 11:28:01 AM »
I just used Beersmith and calculated the mash pH, then added lactic acid additions in the mash profile to get to 4.5.  Then after completing the mash, I ran it off then added the extra lactic acid.  It reduced it to 4.3, so it wasn't exactly the same as adding it to the mash, but it was close.  I soured with Omega Labs Lacto blend of Brevis and Plantarum (a 5 day starter) and it went to 2.9 in 16 hours.  Really sour.

I didn't even bother bringing the wort pH down with lactic acid when using the Omega Labs blend. Just pitched it at pH 5.3 and it still brought it to 3.1 in less than 24 hours. I think it's fast enough to eliminate any worries about infection before it takes hold and drives the pH down on its own.

I can believe that - per Mark, the bacteria reproduces 8 times in the time that yeast reproduce once!


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Offline reverseapachemaster

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Re: Lactic acid and ph adjustment
« Reply #6 on: August 11, 2015, 03:08:43 PM »
Is there any way to calculate how much lactic acid (88% strength) to add to ~11 gallons of wort to get the pH down around 4.5?  I guess I don't know my starting pH yet (assume 5.3-5.5 maybe???) which I'm sure affects the answer.  Just looking for additional advice.  Is this just kind of a "test and see" type thing?  What's a good increment to start with?

You need to test the ph to figure out how much acid is going to drop you to a specific ph. Without knowing the mash ph and the buffers floating around in it you can't know how much acid is necessary to make the drop. A volume that works in one wort won't work in the next.
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