what variables affect final pH in beer?

[Junkyard]

Ive been having some trouble getting a consistent finishing pH in my beers fermented with Chico ale yeast, most often the trouble lies with a higher ph than desired (4.5-4.6)

From what i gather online in other articles it seems that finished beer pH is a variable of overall yeast health. However, I Oxygenate at 1 LPM for 15 minutes during knockout for a 1.5 BBL batch. I Repitch 2L of slurry in each batch and get seemingly very healthy fermentations, with very high attenuation.

Does yeast pitching rate have a profound effect? should i start counting yeast cells? Or is there other variables like brewing water chemistry that I need to consider that have a large effect?

I usually adjust my mash with calcium sulfate for hoppy beers to optain a room temp mash ph of 5.3, then acidify in the kettle to get a kettle ph of around 5.2

heres my latest water report

pH 8.5
Total Dissolved Solids (TDS) Est, ppm 554
Electrical Conductivity, mmho/cm 0.92
Cations / Anions, me/L 9.2 / 9.6
ppm
Sodium, Na 161
Potassium, K 6
Calcium, Ca 27
Magnesium, Mg 8
Total Hardness, CaCO3 101
Nitrate, NO3-N 1.5 (SAFE)
Sulfate, SO4-S 122
Chloride, Cl 19
Carbonate, CO3 1.4
Bicarbonate, HCO3 77
Total Alkalinity, CaCO3 65
Total Phosphorus, P 0.22

[Junkyard]

You aren't adding an external acid? Only relying on the acidification effect of the calcium addition? What estimated final calcium content are you producing in your kettle wort? (PS: you can't really know the Ca content after the mash since their are calcium complexing reactions that drop out Ca, but what is the calculated Ca content?)

Boosting calcium content is not an ideal way of neutralizing excess bicarbonate and producing an acceptable mash pH. High calcium content can hamper the performance of lager yeasts, but it shouldn't really affect ale yeasts. As you point out, the yeast is the component that sets beer pH. If you are reaching a proper mash pH and even post mash acidifying, I can only assume that it is a yeast problem. How many repitches do you use and how is it recultured to pure?

My adjusted water is calculated to around 80 ppm calcium after the calcium additions, i usually add the same amount of calcium to every beer to increase my total calcium at least over 50 ppm (ive heard 50 ppm is the lower limit for calcium for yeast floccing)

I add phosphoric acid during the beginning of the boil if my collected wort ph is too high. (for lighter ABV beers it is usually higher 5.4-5.5) I usually bring the kettle ph down to about 5.2 before i add hops (to get a smoother bitterness). Are you suggesting that i should adjust mash ph with phosphoric instead of calcium?

My repitch rates might be fluctuating some due to different levels of trub in the yeast i collect. Would overpitching or underpitching result in a higher final pH?

I go through about 8-12 generations before ordering a new direct pitch from BSI. We brew quite a few high gravity ales, sometimes repitching from the high gravity beers. One thing that puzzles me; we never have this problem with our West yorkshire ale strain, even with higher gravity beers.

my understanding: Yeast release ions into the wort to decrease the wort pH causing a gradient to take up nutrients. Our fermentations have high krausens, are very thorough, and attenuate very high. (a recent double IPA i brewed attenuated from 1.076 all the way down to 1.006; it ended up at a 4.6 ph)

[Junkyard]

Yes for ales, the rule of thumb for 50 ppm is a good idea to enhance flocculation performance. However, if you lager or filter, then you don't have to have 50 ppm Ca. Your targeted 80 ppm Ca doesn't seem out of place. However, I just noticed that your water supply has a lot of sodium! That could be problematic for flavor too. But I don't expect that it has a big influence on beer pH.

I assume that your water supplier may be performing partial softening of your tap water. This is common in places with rock-hard water supplies.

that water report was from the summer, where my city takes a lot of their water from an underground aquifer in order to keep the temp down below 70 degrees. I've been told that the aquifer is a much different water source than what we get during the winter, which prompts me to do another water report.

Your mash pH results of greater than 5.4 are a little troubling. I find that beers tend to be crisper tasting when the room-temp mash pH is a tenth or two under 5.4 for pale-colored styles. Are you acidifying the sparging water? You should be, since the raw water alkalinity is too high for sparging use without neutralization.

My mash pH is usually lower than 5.4.. the kettle pH sometimes gets up around 5.4-5.5 for lighter styles. As you point out, I havent been doing a good job of adjusting my sparge water, ill Have to make a point of keeping mash pH down around 5.2 and acidify my sparge every time from now on. thanks for the reminder.

All I can recommend is that if your final beer pH is higher than normal and the beers aren't tasting as crisp as you and your customers prefer, add more acid and target lower wort production pH's. I do recommend that you concentrate your pH adjustments on the mashing processes and not rely on kettle adjustments. Properly mashed wort has the correct pH when it hits the kettle and doesn't need adjustment.

Ill make sure to target a 5.2 mash pH from now on. Like you said earlier, maybe it is a yeast issue after all. This american ale strain im using must be a pretty finicky acid producer. Good news is, i just got a correctly sized oxygen flowmeter, and a cheaper milwaukee DO meter to try to track my oxygen rates a bit better.

Thanks for the help Martin.

[dantose]

pH 8.5

With a pH that high, I'd just add a buffer solution https://bsgcraftbrewing.com/ph-52-mash-stabilizer-7

Basically, every step is going to have stuff that could mess with your pH. There is a LOT of chemistry in beer. If you don't want to use the buffer, you should probably track your pH at each step to determine where it's going off. Armed with that knowledge, you can trouble shoot the process at that step to get a more consistent pH.

[AnthonyB]

With a pH that high, I'd just add a buffer solution https://bsgcraftbrewing.com/ph-52-mash-stabilizer-7

Basically, every step is going to have stuff that could mess with your pH. There is a LOT of chemistry in beer. If you don't want to use the buffer, you should probably track your pH at each step to determine where it's going off. Armed with that knowledge, you can trouble shoot the process at that step to get a more consistent pH.

Water pH has very little to do with mash pH. Further, 5.2 buffer has been shown over and over again to not produce reasonable results (not too mention the excess levels of sodium it adds to your resulting water profile).

Water is without a doubt, one of the most important ingredients in beer. Spend the 3 hours of reading to learn how to properly deal with it. Read this book. Use this spreadsheet.

With regards to your water, the amount of sodium is problematic, as watereng pointed out. You need to address that somehow, likely through dilution with some percentage of reverse-osmosis water. Otherwise it is fairly soft, you should be able to build up, with either calcium sulfate or calcium chloride, just about any water profile you want and still hit a correct mash pH.

[Junkyard]

With a pH that high, I'd just add a buffer solution https://bsgcraftbrewing.com/ph-52-mash-stabilizer-7

Basically, every step is going to have stuff that could mess with your pH. There is a LOT of chemistry in beer. If you don't want to use the buffer, you should probably track your pH at each step to determine where it's going off. Armed with that knowledge, you can trouble shoot the process at that step to get a more consistent pH.

Yeah the pH of the starting water doesnt really matter, it can be neutralized easily. In fact lots of municipalities want more basic water so that it is less corrosive on the water pipes. And i agree that 5.2 buffer is garbage.


Anthony- At this point, im less interested in adjusting my water, and more interested in what factors decide the yeasts ability to lower the pH of the wort. Is it simply just pitching rate, oxygen and giving the yeast the proper nutrients, or are there other pieces to the puzzle?

[AnthonyB]

Aside from mash chemistry, the yeast are dependent on the same sort of chemistry principles. More yeast mean faster pH drop but more yeast doesn't necessarily mean more pH drop. They are still subject to the same buffering effects of the original water's hardness, etc. After fermentation is done, yeast health becomes important because if the yeast weren't particularly healthy when you started, they will not be able to do the same tricks as when they originally started and pH will once again rise. This all begins with the proper pH after the boil though because the yeast only have so much capacity for lowering the pH, if you start fermentation really high, the yeast won't be able to do it.

The whole process has to do with something called a proton pump... yeast essentially excrete hydrogen to make a pH gradient which then allows sugars and what not to enter the cell. You can read more about this in a number of brewing books, like this one.

Pitch healthy yeast... but you should really consider doing something about that sodium... high levels of sodium interfere with the proton pump mentioned above... there are a bunch of complicated interactions involving potassium and other trace minerals, really beyond my primitive understanding

[Junkyard]

Anthony, thanks for the input, i've read numerous books on yeast, and i'm familiar with everything you said there. Im just trying to dig a little deeper.


I found this on a homebrew forum
"wingnut:
In my experience, the more yeast re-production during fermentation, the trend toward lower beer PH. iee. Higher initial pitch rates tends to keep beer ph higher then lower pitching rates.

Obviously, there are a great many other factors in play as well, but pitching rates are one of the variables. Salts, acids, malt buffering and ph, etc are bigger factors that set up the initial conditions. "

seem true?

[AnthonyB]

Anthony, thanks for the input, i've read numerous books on yeast, and i'm familiar with everything you said there. Im just trying to dig a little deeper.


I found this on a homebrew forum
"wingnut:
In my experience, the more yeast re-production during fermentation, the trend toward lower beer PH. iee. Higher initial pitch rates tends to keep beer ph higher then lower pitching rates.

Obviously, there are a great many other factors in play as well, but pitching rates are one of the variables. Salts, acids, malt buffering and ph, etc are bigger factors that set up the initial conditions. "

seem true?

The stuff I have seen seems to indicate the opposite. Lower pitching rate ends up with higher pH. Like this.

[Junkyard]

thx for linking that, ive actually seen that on braukaiser before but its nice to get a refresher. that is actually what i took to heart till now but at this point I really dont know what to believe. Ive had very vigorous fermentations that were blowing out of the PRV (only about 1/4 of our fermentations with american ale yeast end up blowing off) and the beer has ended up to be a 4.5-4.6 pH. I know yeast strain is part of it. Would hoppiness be another factor?

[frenchc]

I'm curious if you have you monitored the ph over time? Are you sure it doesn't actually hit the target ph then go back up? Or does it just never hit the target range? If it gets lower then rises, it could be the yeast are getting stressed, maybe sitting too long on the beer? I've heard lots of trub can clog up the yeast membranes and possibly cause additional stress to the yeast that might be a consideration. Also, when are you dumping the yeast? There are lots of tests you can do to test your yeast vitality.

[soia1138]

"Would hoppiness be another factor? " Yes, you will get a Ph rise if you are dry hopping, so if you are already riding a little high, it may bump it up into that undesirable range. Higher gravities will also stress the yeast more obviously and cause a smaller overall drop. We brew a double IPA that was ending up in that range as well, with no water adjustments I was able to get it into acceptable range by both pitching a little more and adding oxygen (we previously did not oxygenate for our dry yeast pitches, only rehydrate). All our lighter SRM beers will start out at just about Ph 5.2, some will finish at around 4.1-4.2, others starting out at higher gravity will finish 4.3-4.4.

[Junkyard]

I'm curious if you have you monitored the ph over time? Are you sure it doesn't actually hit the target ph then go back up? Or does it just never hit the target range? If it gets lower then rises, it could be the yeast are getting stressed, maybe sitting too long on the beer? I've heard lots of trub can clog up the yeast membranes and possibly cause additional stress to the yeast that might be a consideration. Also, when are you dumping the yeast? There are lots of tests you can do to test your yeast vitality.

I usually take a ph reading the morning after pitching which is usually in the 4.7-4.6 range, then i wait to check it again until im checking final gravity. it might be worth doing a few more checks to narrow in on what you mention. We harvest our yeast into containers for repitching, and leave the rest of the yeast in the bottom of the fermenter until we rack the beer into kegs. (usually about 3-4 days, sometimes more if dry hopping)

"Would hoppiness be another factor? " Yes, you will get a Ph rise if you are dry hopping, so if you are already riding a little high, it may bump it up into that undesirable range. Higher gravities will also stress the yeast more obviously and cause a smaller overall drop. We brew a double IPA that was ending up in that range as well, with no water adjustments I was able to get it into acceptable range by both pitching a little more and adding oxygen (we previously did not oxygenate for our dry yeast pitches, only rehydrate). All our lighter SRM beers will start out at just about Ph 5.2, some will finish at around 4.1-4.2, others starting out at higher gravity will finish 4.3-4.4.

Ive also heard that some other commercial IPA's finish very high in pH, one of ballast point's IPA's for example. I already pitch quite a bit but i'll have to start increasing my oxygenation for high gravity beers even further...

[dstar26t]

Just a note on your practice of adding Gypsum to the mash to lower mash pH...
This is a fine practice but keep in mind that your water report lists sulfate as sulfur which is what the -S is in SO4-S. Your full sulfate level will be the measured sulfur times 3 which is 366 ppm sulfate in your case. I've never used more than 350 ppm sulfate and only for hop forward beers. Your Chloride is fairly low so an addition of CaCl2 may work well for lowering mash pH if you're getting a harshness from hops from a high sulfate concentration. Maybe a high sulfate harshness lead you to acidifying the kettle to 5.2? You may not be able to lower mash pH enough without overdoing it with Chloride though, which I like to keep below 100 ppm.

Nate

[JSChicago]

Final Beer pH Thread Bump

I'd like to bump this thread and see if anybody has new thoughts. Our mash pH is consistently 5.2 or 5.3. According to Bru'n Water, all our minerals are in the green after we adjust with various combinations of CaCl, gypsum, and phosphoric. We pitch 1 million cells per mL per degree Plato. We use a DO meter to measure oxygenation into the fermenter and have tried everything between 8 ppm and 16 ppm. We just started adding zinc, but that hasn't fixed the problem. We measure pH most days during fermentation. We consistently see our pH drop to 4.6 or 4.7 and then stall out. When we dry-hop, it tends to rise another .2. We get this problem with both repitches and fresh pitches from the lab. We get vigorous fermentations. We've calibrated our pH meter. We also use the Chico strain. Our wheat ale, which is fermented with a saison yeast and not dry-hopped, will get down to 4.3 or 4.4, which is also higher than we'd like. We knock yeast off the bottom of the fermenters every couple days. Our cones are jacketed.

Going through that Bamforth fishbone...

> Yeast strain? Junkyard and I both use the same yeast. I've not found anything out there comparing the relative acid production of different yeast strains. We'll switch, if that's what it takes.
> Pitch rate? We haven't tried changing this, because we seem to be using the consensus rule of thumb. Most of the time, if I hear brewers deviating from this rule of thumb, it's to pitch lower, but that would move our pH the wrong direction.
> FAN? In our most problematic beer, we use about 80% 2-row, 10% flaked wheat, and 10% malted rye. We should be fine there, right?
> Temperature? We ferment at 66.

Any thoughts will be greatly appreciated.

John