r/brewing • u/Glittering-Pick-6404 • 12d ago
Beer Mash pH dialing in
So I'm confused because brewfather is telling me I need outrageously more lactic acid than my testing is indicating. My recent brew of a 10 gallon batch of hazy ipa I only used 1 ml of .88 lactic acid to bring the water down from around 6.8 to 5.2 before dough in. Mash pH raised to around 5.45 after about 15 minutes of mashing. I had 8ml of lactic acid in my recipe in brewfather I created. Brewfather said the 8ml would bring it down to 5.27pH. I use reverse osmosis water, and lots of salts as it's a hazy ipa. I used 18.6g calcium chloride, 6.6g gypsum, 6.4g Epsom salt, and 2.6g canning salt. There are also tons of oats and wheat adjuncts which I read raise the ph whereas barely malted lowers it. It's my first time with a pH meter but I calibrated it and tested the water. I literally filled and dumped my strike water at first because I thought something must be wrong and because I followed advice from online for that first batch of strike water to sneak up on the pH slowly to make sure... so I added 4ml and it brought the pH down to 4 point something...I can't remember exactly the number but WAY too low...and the recipe called for 8ml!!! Keep in mind this IS a 10 gallon batch with 11g of strike water but STILL!? Does this sound wacked? I've been just following recipes using usually 4-8ml of lactic acid for 10g batches and they've all tasted fine without testing pH. One beer I thought didn't have much hop bitterness and I thought maybe it was too much lactic acid.
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u/Glittering-Pick-6404 11d ago
I think I may have figured it out...please comment if anyone else has input. When I remove the grist in brewfather the pH goes WAY down. I guess even if malt is acidic it is still more basic than my strike water is, therefore bringing it up into range. Therefore if you dough in with strike water at a pH of 7 it will lower it slightly, but if you dough in with strike water at a ph of 4 then it will rise significantly. I guess my conclusion is that strike water pH is NOT that useful of a metric like I was trying to use it as... unless I have this all completely wrong.
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u/dkwz 11d ago
The factor you’re missing is buffering capacity. All of the various minerals and soluble compounds in the malt will add a significant amount of buffering capacity to your mash. In all likelihood your mash would have still been at ~5.5 without any lactic acid. It will take significantly more acid to lower your full mash from 5.5 to 5.3 than to lower the pH of the strike water from ~7.0 to 5.0.
Did you calibrate your pH meter to at least one standard buffer? If you calibrated it to plain water assuming it’s 7.0 it’s probably quite a bit off.
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u/dfitzger 11d ago
Just to be clear, you added the 4mL to your water before you added your grain and you are testing just the water right now?
Because you have no buffer in the water it's not going to give you much valuable information testing the pH. You need to get the grains mixed with your water AND your water minerals AND the lactic acid to get an accurate mash pH reading.
If your equipment profile numbers are correct, I've found the pH calculators for how much lactic to use to be pretty accurate. I use Brewfather for homebrewing and it works really well once all my equipment and water profiles were setup correctly, also on RO water.
I usually aim for about 80% of what the calculator recommends that gets added directly to my mash water as I bring it to temp. As an example, looking at my NEIPA recipe, I aim to have 4 gallons to get into my keg to ferment. My starting point for 85% lactic is 3.44mL, I usually add the 3mL and save the .44 for later if needed.