Kettle Sour pH Balancing w/ Lactic

wareaglefan23 · Dec 5, 2015

Hey guys, I know this isn't super wild but I thought there would be some helpful information. I'm planning to brew a simple kettle soured berliner using only wheat DME for mash. It's already 55/45 wheat and light barley, so it should be perfect or a basic weisse. There is a TL;DR at the bottom to make things easier.

The idea is really to get rid of the 3-4 lbs of DME I've had sitting for 6 months, so it'll be a 3 gallon batch to give about 1.045 OG. I'll boil for ~10 minutes to deoxygenate and sterilize, after which I'll drop it to ~90-100 F, bubble through some CO2, and pitch in a good belly shot and a probiotic pill, holding for 24-48 hours. Boil, add yeast, viola. Beer!

Heres the issue. I know I want to drop the wort pH to 4.5 before adding the LAB probiotics. What I don't have is any way to measure pH. I'm not going to buy a meter just for this, and test strips aren't accurate enough in my experience. I've got 88% lactic acid, but I have no idea how much to add to drop the pH to my target level. Any ideas?

TL;DR - How much 88% lactic to add to 3.75 gallons (boil volume) 1.045 Wheat DME wort to drop pH to 4.5?

Qhrumphf · Dec 5, 2015

Depends on your water source. The higher the alkalinity, the more acid it's going to require. So there's really not a way to answer. Best course (really, the only workable course, sorry to say) is to buy a pH meter. You could try plugging your water data into a calculator and try to approximate it that way.

wareaglefan23 · Dec 5, 2015

Tap pH in my area is very neutral. Assume 7.3 pH. I am fine with rough estimates, I just don't know the general range.

Qhrumphf · Dec 5, 2015

Tap pH isn't nearly as relevant as alkalinity.

Agate · Dec 5, 2015

Really no way to tell you without knowing your water and buffering capacity of the DME. However, you really only need to be under around 4.8 for good head retention. I would use 5 ml and call it good.

Why are you concerned about dropping pH to 4.5? Not necessary from a contamination point of view...

SanPancho · Dec 5, 2015

considering that you're in a major metro area, i cant imagine your local water dept doesnt have any reports for your water quality/minerals/etc. in fact i'd bet that there is a link somewhere in these forums to somebody else in atlanta who's posted the annual report.

get a hold of that report, then go to either ezwatercalculator or bru'nwater and download a spreadsheet. they're both free, but feel free to donate a few bucks. enter your local water average ppms for hardness/calcium/mag/sodium/etc. once you spend about 10 minutes entering your basic info for your local water- save that sucker as a template.

then everytime you brew a recipe you copy the file with your recipe name, and then can add in your grains, gypsum/cal chloride/epsom/etc. to tailor each brew to right pH and ion levels.

finally, they both have lactic acid addition calculators so you should be able to get a good idea of how much to add to get down to 4.5. i think brun water will also let you use acids of different strengths (lactic is typically either 25 or 88% in my experience). brunwater will actually let you calculate for phosphoric acid as well if i recall correctly. ezwater supposedly has that feature, but ive never been able to find it and nobody ever responds to emails.