I’ve been using bru’n successfully for years, but have recently started doing much lighter beers. Like a recent helles, and Pilsner. I’ve realize that when my SRM is under five, my pH seems to be way off. I’ve done other beers in between like IPAs and Marzens and the pH is very close to calculated, but when I do very light beers, they are way off. I’m calculating/shooting for around 5.3, and the mash pH is coming out right around 5.6 for these beers. I use acid malt to adjust pH downward instead of adding acid. Any ideas?
I recently listened to Martin speak about when to take a sample for the pH reading. it’s often said about 10-15 min after mash in but he recommends 45 min in. Of course, the mash is nearly (if not completely) finished by then so it’s too late to do anything.
Over the years, I’ve used Bru’n Water, MpH and BNW in BeerSmith water model, and Brewer’s Friend. Of the four I’ve used, my closest estimates, especially lately, have been with Brewer’s Friend followed by Bru’n Water. The furthest between my actual to estimate is .1 pH at 10 min and is usually spot on or just .0X different at 45 with Brewer’s Friend.
Some other brewers in my area prefer Bru’n Water.
Regardless of the model you settle on you’re only going to get estimates given the huge degree of variables due to the agricultural products we use.
“All models are wrong, but some are useful" is a well-known quote attributed to George E. P. Box. For me, Bru’n Water and Brewer’s Friend are more useful than MpH and BNW in BeerSmith water model.
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I’ve been trying to tell people about Martin’s advice for years, but it always seems to fall on deaf ears. Glad to hear you mention it.
I read or heard somewhere that pH readings during the mash are more about doing better next time than changing anything in the current batch.
But you didn’t say what you’re trying to fix by adjusting the pH. Are you getting poor mash efficiency in these batches? Are you unhappy with the final product?
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Or is 5.6 perfect, and 5.3 too low? Depends on the temperature at which you are measuring. Fall down some rabbit holes:
https://www.homebrewtalk.com/threads/will-it-mash-at-ph-5-00.667992/page-2#post-8653242
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Have you calibrated your pH meter lately? I calibrate mine about once a month. How long has it been since you replaced the probe? The probes normally last about two years. If you don’t cool the sample to room temperature, the lifetime of the probe is significantly diminished. What is the starting pH of you brewing liquor? I use R.O. water from a local water company and many times the pH is above 8.0. I acidify with phosphoric acid to get it down below 6 before adding minerals and my pH falls in line with what Martin’s calculator predicts.
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Martin’s advice is to measure at the temp your meter is calibrated for.
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This is THE MOST IMPORTANT question. I can count the number of pH measurements I made in almost 35 years of homebrewing on one knarled hand. I am not saying to not measure pH if that’s what you want to do but go back to this question
I am not surprised since brewing dogma is darker grains lower pH thus lighter beers shoukd have a higher pH
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Mine is calibrated at 77 degrees F. I normally cool my sample to around 80 degrees or so.
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It’s not dogma, it’s science
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pH 5.5 - 5.6 is the textbook recommendation from the TU Munich, if you believe they have any authority on the matter…
For Helles, it’s not a problem at all.
Not sure what your initial water is. Having some buffering capacity helps avoid drastic pH swing during the mash.
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Depends what you are trying to make. For Helles the mash is well over several hours. The glycoprotein rest alone is 40+ minutes.
180 minute long step mashes, even with infusion, are pretty much de rigeur.
Calibration with sauergut during this period is not unheard of. It’s a mild acid and thus easy to work with.
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Probably need more details to help. What’s your water like, and have you sent it in for a water report recently?
Was this in-person, or is there a video or presentation that you could link to?
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Besides the video, he also talked about it on Experimental Brewing
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I should’ve put this in the original post. I use RO Water that I make at my own house . I cool the wort down to 65 to 70° before taking the pH. I calibrate my pH meter every single brew day. Maybe it has to due to variation with the acid malt I use. I think I’ll start using lactic acid instead of acid malt.
How often have you changed your RO filter, and have you taken a TDS reading to see if it’s working properly?
Do you use any other salts? What kind of sparge do you do? For just RO water, the amount of acid you’re going to need depends on the mash thickness – about 3-4% acid malt by weight for a traditional sparge (or batch sparge), but double that for a no-sparge due to the much larger quantity of water. For a sparge, you would generally use another acid addition to bring the pH of the sparge water down. These are rough estimates I got from Brun’Water but they line up with my experience brewing very light beers.
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Ahhh, cool, just listened… FYI this episode does not appear on Spotify or Apple Podcasts (I listened via your site). Not sure what’s happening there… 
I’ve often heard, and parroted myself, that “by the time we take the pH measurement it’s too late to do anything for this beer. Take notes and make the adjustment on the next beer.” …but I have been thinking about this advice.
I agree proper mash pH is important for the enzymatic processes, fend off tannin extraction, etc. While making post mash sweet wort is important, it’s not the end game. As @DrewC alludes to: the final product is even more important. As brewers we’re in control of the entire process, not just the mash.
So, if the mash pH is found to be off target, adjustment should be made, even though the mash may be nearly complete, because it will affect the post boil wort pH into the fermenter to set up the final beer pH. pH (and many other characteristics) can be adjusted at many points along the process path.
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