How to lower the PH of wort to 4.5 Pre-Fermentation

[Hojo3322]

Howdy all,

I am looking for a bit of your advice. Recently I was inspired by Jeff Crane's AHA talk on how to make an acid beer. It's up on AHA's website and is a great talk. One of the things he suggests is to lower the PH of the wort to 4.5 before pitching some lacto. From my understanding lowering the PH to 4.5 pre-pitch helps inhibit a protein-destroying enzyme that Lacto produces.

Now here is the part I need your help with, i picked up some food grade liquid lactic acid 88% concentration. I anticipate my wort PH going into the fermenter to be in the 5.4 range. How much of this 88% concentration liquid lactic acid should I add? How would I go about determining this? Any help would be greatly appreciated

 

[FirstAidBrewing]

That really depends on the grain bill and strike water, as those two factors determine what the starting pH of the mash is. Are you using RO water? What will the grain bill be? Any idea as to what alkalinity the water is?

I know personally that for a light ale my water would probably need 6 to 7 ml of lactic acid to get into that 4.5 range, but your water might not be like mine

 

[BrewerBrad82]

Do you have a good pH meter? You can always draw a sample of known size and use a pipette to dose the sample with the lactic acid until you hit 4.5. Then just scale that measurement up to your full batch volume.

 

[ricshayne]

As said above it depends on your grain bill and water.
If you're going to be messing with your water you really should download the Bru'n Water spreadsheet

https://sites.google.com/site/brunwater/

 

[mchrispen]

Adjusting into the fermenter would most likely require you to get the entire wort into your desired pitching temperature range and pulling a liter. Dose that liter carefully with 1 ml of lactic acid at a time until your meter shows the target pH. Scale that result to the full volume of your fermentation. Without a pH meter, you are shooting blind. You could potentially use pH strips for this, but they are not all that reliable.

Derek Springer did a talk at NHC on sour worting - http://www.fivebladesbrewing.com/berliner-and-beyond/ - and makes some general recommendations in amounts that might work for you.

 

[MindenMan]

I don't know if you have a metric measuring device for your Lactic acid, but 1 teaspoon is 5 ml, so 1/4 teaspoon should be 1.25 ml, etc.

 

[conan71]

I just did this myself and am in the process of doing a full sour mash. I cannot agree more about the need for a pH meter to do this reliably. As I have a RIMS system, I can make an acid addition, let it circulate for 5 min, recheck and add more acid as needed. I suppose I could take a measured sample then run the calcs to figure the ultimate addition, but I’m more comfortable simply adding and testing.

After starting the sour mash at just under 4.5, my pH was at 4.0 24 hours later. Will test again this evening to see how my mash is going.

 

[Hojo3322]

thanks for all the responses. I have a basic understanding of water treatment. The 5.4 PH represents what I predict the PH of the wort will be in the fermenter. I am all set with controlling my mash PH. I am more concerned with being able to move the wort PH down to 4.5 while in the fermenter before I pitch lacto. This may be a very newb question but does the grain bill play a roll with the wort PH adjustment even after the wort has drained from the MT?

While I would like to have pin point control, for my first shot at an acid beer I am looking for ball park figures to get it down to 4.5 PH pre pitch. I do have a PH meter but would much prefer to have a ballpark amount of lactic acid to add instead of scaling up off a small sample. Here is the grain bill if it helps:

Batch Size (Gal): 9 G (Parti-gyle brew day)
4 Gallons (IPA) OG 1.067
5 Gallons (Acid Beer) OG 1.045

70.88% - 11.39 lbs. American 2-row
20.67% - 3.32 lbs Vienna Malt
6.89% - 1.11 lbs Flaked Oats
1.56% - 0.25 lbs Acid Malt

Target Water Profile 74 CA 5 MG 15 NA 84 CL104 sulfate PH 5.47 (used EZ water calc)


thanks in advance for the help!

 

[mchrispen]

I am more concerned with being able to move the wort PH down to 4.5 while in the fermenter before I pitch lacto. This may be a very newb question but does the grain bill play a roll with the wort PH adjustment even after the wort has drained from the MT?

Your estimate is for mash pH and doesn't account for the pH drop in the boil. Assuming a 60 minute boil, your final boil pH should be somewhere in the range of 5.1. You could account for that drop, and use EZWater to estimate the lactic acid addition to 4.5. So if we assume your actual wort pH is 0.3 points lower than your estimated mash pH, you could add the lactic to achieve an approximate mash pH of 4.8 in EZ. Again - I would not recommend doing so without the meter - but that should get you into the ball park.

If this is no-boil wort into the fermenter, then the above should be ignored. Just use EZ to figure out how much lactic needed to get to 4.5 from 5.4.

 

[Qhrumphf]

As mentioned, you really need a pH meter for it. With the sour mash I just did, my grain bill in tap water alone got me a pH of ~6, it took ~4ml of 88% lactic to bring it down to ~5.4 for the conversion rest. And then it took almost 15ml to bring it down to 4.47 prior to innoculating with grain.

Point is, you may need more than you think. My suggestion is to do what I did, add a little acid, measure, add more, measure, add more, and measure again, until you hit where you need to be.

 

[SpeedYellow]

Like mcrispin said, use EZ Water to get in the ballpark. I've done this a couple times with success. Obviously a pH meter is required. On a recent Berliner Weisse, I needed about 6 mL lactic acid, but on a bigger beer I needed like 11 mL. Both times, EZWater was in the ballpark -- just use about 3/4ths of what it says, then take a pH reading and extrapolate to get your 2nd addition of lactic. It's of course much quicker/easier to do with cooled wort.

 

[Hojo3322]

use EZWater to estimate the lactic acid addition to 4.5.

thank you very much for the input. I completely forgot there is an option for lactic acid adjustment in EZ water calc.

Both times, EZWater was in the ballpark -- just use about 3/4ths of what it says, then take a pH reading and extrapolate to get your 2nd addition of lactic. It's of course much quicker/easier to do with cooled wort.

adding 3/4 of what EZ states and fine tuning with the meter sounds like the way to go, thank you