Is targeting the mash pH the wrong goal?

[SpeedYellow]

While sampling some beers at a recent brew club meeting, some beers seemed flat, quite possibly due to high pH. Which got me to thinking -- shouldn't we be more focused on final beer pH instead of mash pH? As we know, there's little to no correlation between mash pH and beer pH. So why don't we talk more about final beer pH?

I'm not suggesting we ignore mash pH, only that perhaps we're missing a more important factor.

 

[GilaMinumBeer]

Can you be certain they weren't just poorly carbonated? Water chemistry can also cause a dull perception of the beer.

 

[mabrungard]

Yeast have a large role in setting the beer pH. It is more difficult to affect beer pH at the brewers level, but you can influence it to some degree by manipulating the mash or wort pH.

 

[wardens355]

What makes you settle on pH being the issue? Do you mean flat as in low-carbonation? Or flat as in dull? Did you measure the pH?

 

[SpeedYellow]

Yeast have a large role in setting the beer pH. It is more difficult to affect beer pH at the brewers level, but you can influence it to some degree by manipulating the mash or wort pH.

Agreed, but it seems like it would be pretty easy to adjust the beer pH a couple points down if needed with lactic or phosphoric acid. Whether or not it would help remains the question. But it's certainly easy for a brewer to find himself with a beer with too-high pH. As we know, for a given recipe, OG, and water profile, some yeasts (or bad yeast health/conditions) won't bring the pH down enough.

What makes you settle on pH being the issue? Do you mean flat as in low-carbonation? Or flat as in dull? Did you measure the pH?

I meant dull. I'm guessing pH problems only from how I've read it manifests-- dull, insipid beer where nothing pops. These beers had no clear flaws except for this dullness. When you're trying several beers together, this flaw really jumps out at you.

 

[ajdelange]

While sampling some beers at a recent brew club meeting, some beers seemed flat, quite possibly due to high pH.

How do you conclude the pH was responsible? Did you measure it? Did you have info on the pH of the mash?

To begin with I am not sure whether 'flat' means lacking carbonation or dull in flavor. As the former has nothing to do with pH (except that 1 vol. carbonation will lower beer pH by about 0.1 pH) I'll assume you mean the latter. And I see in #5 that the latter is what you meant. Dull flavors in beer are associated with high mash pH. Adjusting the pH of a beer which has been mashed at high pH will not evoke those missing bright flavors which are formed in the mash tun.

Which got me to thinking -- shouldn't we be more focused on final beer pH instead of mash pH? ... So why don't we talk more about final beer pH?

We should be cognizant of beer pH as well as mash pH but mash pH control is the sine qua non of good beer. Get mash pH right and pH tends to be on track for the rest of the process right through to the finished beer and that is doubtless why we don't tend to monitor the finished product so closely. If mash pH is right I'll find my kettle pH to be right and if kettle pH is right I'll find wort pH to be right within 12 hrs or so provided the yeast pitch is healthy. If I find good wort pH at 12 - 24 hrs the yeast will put the beer pH where they want it to be.

Some brewers do trim final beer pH with acid.

As we know, there's little to no correlation between mash pH and beer pH.

There is some. Clearly if you present high pH, high alkalinity wort to a bunch of yeast they will have to put more metabolic energy into acid secretion to get to the pH they like than if you present them more favorable conditions and they may not get all the way to where they want to be.

I'm not suggesting we ignore mash pH, only that perhaps we're missing a more important factor.

If final beer pH is off after proper mash and kettle pH's have been obtained then clearly there is a problem with the yeast pitch or fermenting conditions. This is diagnostic and should be addressed. Adding acid to a beer exhibiting improperly high pH for the style isn't going to fix it though. OTOH we can't say that adding some acid to an otherwise good beer might not improve its flavor profile or, at least, make it more to your liking.

 

[wardens355]

I would be interested in comparing several similar pale beers that have (1) high mash & kettle pH, (2) acceptable mash pH, but alkaline sparge that resulted in high kettle pH, and (3) acceptable pH in all steps. I don't feel like conducting that experiment, though... Unfortunately you don't have the pH info on the beer, so it is hard to make the leap that mash pH is a wrong goal.

If you target mash and sparge pH at the mid-lower end of the acceptable mash range, you should be able to reduce worries about high pH in the final product.

 

[SpeedYellow]

If final beer pH is off after proper mash and kettle pH's have been obtained then clearly there is a problem with the yeast pitch or fermenting conditions. This is diagnostic and should be addressed. Adding acid to a beer exhibiting improperly high pH for the style isn't going to fix it though. OTOH we can't say that adding some acid to an otherwise good beer might not improve its flavor profile or, at least, make it more to your liking.

Hmmm. For a beer with proper mash and kettle pH, yet high final beer pH, you're saying we can't improve it by trimming with some lactic acid. Why not? If "mash pH control is the sine qua non of good beer" and we've achieved it, then haven't we made a "good" beer (with the exception of high beer pH)? So if high pH is the problem, adding acid is a simple solution.

Of course, I'm playing devil's advocate to some extent. I'm just struggling with simply writing-off a 5-gal batch that has a high beer pH and saying "oh well, i'll pitch better/more/healthier yeast next time."

The big problem is that yeast are so damn fickle. Can't figure those buggers out.

If you target mash and sparge pH at the mid-lower end of the acceptable mash range, you should be able to reduce worries about high pH in the final product.

I haven't found this be to the case, even when my careful yeast efforts result in seemingly-healthy fermentations. E.g. I've had lagers finish at 4.7 - 4.8 pH inexplicably. So I'd assume that others are having the same problems, whether they know it or not.

 

[ajdelange]

Hmmm. For a beer with proper mash and kettle pH, yet high final beer pH, you're saying we can't improve it by trimming with some lactic acid. Why not? If "mash pH control is the sine qua non of good beer" and we've achieved it, then haven't we made a "good" beer (with the exception of high beer pH)? So if high pH is the problem, adding acid is a simple solution.

High pH isn't the problem. It is a symptom of the problem which is poor fermentation for whatever reason.

Of course, I'm playing devil's advocate to some extent.

Devils advocacy can stimulate thought and discussion so I'm all for it.

I'm just struggling with simply writing-off a 5-gal batch that has a high beer pH and saying "oh well, i'll pitch better/more/healthier yeast next time."

That's clearly what you need to do but try tweaking the beer you have that is too high in pH. It won't fix the problem but it might make the beer more palatable.

The big problem is that yeast are so damn fickle. Can't figure those buggers out.

That has not been my experience. Either they do what they are supposed to do or fail miserably because the pack is too old or was abused in storage/shipping or I failed to oxygenate (all the O2 went out the back of the flow meter instead of into the wort on 1 occasion) or something like that. Yes, there are some variations in final pH but they are modest.

I haven't found this be to the case, even when my careful yeast efforts result in seemingly-healthy fermentations. E.g. I've had lagers finish at 4.7 - 4.8 pH inexplicably. So I'd assume that others are having the same problems, whether they know it or not.

Lagers tend to have higher finsihed pH's. Not sure I've ever had one come out as high as 4.8 but I've probably seen 4.7 and certainly 4.6.

 

[wardens355]

I haven't found this be to the case, even when my careful yeast efforts result in seemingly-healthy fermentations. E.g. I've had lagers finish at 4.7 - 4.8 pH inexplicably. So I'd assume that others are having the same problems, whether they know it or not.

Do you have records of lagers you have brewed with a pre-boil pH around 5.2-5.3 that have ended with a finished product of 4.8? Just curious. I don't measure pH following fermentation, so I have no clue where my beers end up. I can measure my current batch of lagers and ales tonight to see (they are all mostly carbonated, not sure if that matters for this pH discussion).

 

[ajdelange]

I can measure my current batch of lagers and ales tonight to see (they are all mostly carbonated, not sure if that matters for this pH discussion).

Yes it does. CO2 forms carbonic acid. Based on a wag at the buffering capacity of beer I estimated that 2 volumes will drop the pH by 0.1 pH. Decarbonate before measuring.

 

[wardens355]

Measured pH of several beers:

IPA (Wy1217) - 4.72
Blonde (WLP001) - 4.78
Kolsch (Wy2565) - 4.09
Pilsener (Wy2278) - 4.54
Marzen (Wy2206) - 4.45
Porter (Wy1318) - 4.28

I generally target a full volume (pre-boil) pH of 5.3-5.4, but was hitting within +/- 0.05 consistently, so stopped measuring actual kettle pH a while ago. I may have to start doing that more routinely. I am using a Milwaukee 102 pH meter, calibrated before each use. Poured tasters, let sit, stirred with a fork for a bit to dissipate carbonation.

The IPA and blonde have a fairly high finished beer pH, which was a bit surprising based on comments regarding lower pH for ales. For $hits and giggles, I poured a couple tasters of the IPA and added a few drops of 85% phosphoric acid to one to reduce the the pH to around 4.2. The perception was a tiny bit more of a 'pop', or crispness on the palate for the reduced pH taster. The unmodified IPA had a tad more warmth and lingering sweetness. Not sure if the adjustment was that big of a game-changer. I recently started aiming for pre-boil pH around 5.2, so I may just start measuring pre-boil pH and adjusting to 5.0-5.1 every batch to see what affect that has on the beers. Interesting that the Kolsch had the lowest pH. I anticipated this, as it is very crisp and borders on tart.

Since I tested all these beers and messed around with pH adjustment, I am fairly boozed up. Got a ticket for not having a front license plate today, gonna walk down to the store and grab some zip ties to shed some of the buzz. Cheers .

 

[wobdee]

Lately I've been researching this and I'm going to try targeting a higher mash PH and adjust down in the kettle and see if it makes any difference.

View attachment 1438738263510.jpg

 

[mabrungard]

Interesting that the Kolsch had the lowest pH. I anticipated this, as it is very crisp and borders on tart.

If you used the German Ale yeast, the low pH may be explained with that. It is reputed to be the highest acid producing yeast and typically has a lower finishing pH than other ale yeasts. Another typical result is that most ale yeasts finish with a lower pH than lager yeasts.

 

[wardens355]

If you used the German Ale yeast, the low pH may be explained with that. It is reputed to be the highest acid producing yeast and typically has a lower finishing pH than other ale yeasts. Another typical result is that most ale yeasts finish with a lower pH than lager yeasts.

I used the Wyeast 2565 Kolsch strain. The interesting thing I found from measuring pH of various beer is that the two american ales had the highest pH of all, which was not expected based on most references I've found.