The subtleties of pH

[Queequeg]

So like many all grain brewer I manage my pH through the use of acid malt and PA additions as well as adjusting the hardness of my water profile.

I have for most part aimed for a target mash pH of between 5.2-5.5, specifically 5.3. The exception to this being stouts which I mash at 5.5.

My understanding is that a mash pH of 5.3 is optimal for maximum conversion of starch and that the higher pH of 5.5 results in greater fullness and smoothness of roasted malts.

However recent reading around the topic have indicated to me subtle nuances that can be achieved for different mash pH's within this range of 5.2-5.5.

Another thing I have always done is acidify my sparge water with PA down to a pH of around 5.5. This was simply a safety measure to avoid tannin extraction and to help the kettle pH fall correctly.

Up to now I have not measured kettle pH. But I want to start measuring and adjusting (if necessary) kettle pH at the start and end of boil.

I have also read that some yeast acidify more than other during fermentation.

There is a lot of conflicting information around the net, so I have made this post to gain some clarity. Could someone please explain the following

Mash pH effects on saccrification- in terms of which pH is optimal
Mash pH effects on bitterness perception of alpha acids -if this is separate from kettle pH
Mash pH perception of crispness or fullness of mouthfeel
Mash pH perception roast grains and crystal malts

Kettle pH effects on bitterness perception
Kettle pH effects on hot break, clarity
Kettle pH of hop flavor and aroma

What the optimal pH in each instance to achieve the desired result and what pH should my beer be prior pitching and at FG?

Sorry for the massive scope, but there is a lot of conflicting information around.

Cheers

 

[specharka]

So like many all grain brewer I manage my pH through the use of acid malt and PA additions as well as adjusting the hardness of my water profile.

I have for most part aimed for a target mash pH of between 5.2-5.5, specifically 5.3. The exception to this being stouts which I mash at 5.5.

My understanding is that a mash pH of 5.3 is optimal for maximum conversion of starch and that the higher pH of 5.5 results in greater fullness and smoothness of roasted malts.

However recent reading around the topic have indicated to me subtle nuances that can be achieved for different mash pH's within this range of 5.2-5.5.

Another thing I have always done is acidify my sparge water with PA down to a pH of around 5.5. This was simply a safety measure to avoid tannin extraction and to help the kettle pH fall correctly.

Up to now I have not measured kettle pH. But I want to start measuring and adjusting (if necessary) kettle pH at the start and end of boil.

I have also read that some yeast acidify more than other during fermentation.

There is a lot of conflicting information around the net, so I have made this post to gain some clarity. Could someone please explain the following

Mash pH effects on saccrification- in terms of which pH is optimal
Mash pH effects on bitterness perception of alpha acids -if this is separate from kettle pH
Mash pH perception of crispness or fullness of mouthfeel
Mash pH perception roast grains and crystal malts

Kettle pH effects on bitterness perception
Kettle pH effects on hot break, clarity
Kettle pH of hop flavor and aroma

What the optimal pH in each instance to achieve the desired result and what pH should my beer be prior pitching and at FG?

Sorry for the massive scope, but there is a lot of conflicting information around.

Cheers

I’m not gonna be able to answer everything, as I don’t want to inject any misinformation into the conversation. A better resource such as Martin Brungard might be able to provide a more comprehensive answer.

Alpha and beta amylase are optimized around a mash pH of 5.40. The mash pH will gravitate towards this value over time, so typically when we refer to measured mash pH it is taken 15-20 minutes into the mash vice at dough-in or mash out.

Mash pH will always be higher than kettle pH due to precipitation of organic compounds, and AFAIK there’s no real difference between kettle pH and final beer pH with respect to the bitterness perception of alpha acids. You can acidify during the boil or afterwards to achieve your desired effect.

For a crisper mouthfeel, you will want to target a lower mash pH (5.2-5.3) and a higher sulfate level, and vice versa. Yeast selection also plays a tremendous impact on the beer’s finish. Lager yeast strains are noticeable for being able to produce a crisp finish despite a relatively high mash and kettle pH.

Roast and crystal malts have a larger proportion of acidification than pale and base malts. They also have a more tannins than base malt, which is why a higher mash pH is encouraged when brewing stouts to prevent astringent compounds from leaching into the mash.

While isomerization of kettle hops reduces pH, dry hopping actually increases the finished beer pH. Which is why brewers of hoppy ales tend to acidify post-boil to prevent a muddled finish from a high beer pH.

Your optimal pH is going to differ from brew to brew, but generally speaking, you want to target a mash pH of 5.3-5.5, a post-boil pH of 5.0-5.3, and a post-fermentation pH of 4.3-4.6. YMMV

 

[Queequeg]

So in an attempt to try and further understand pH in the text of mashing I consulted my copy of Briggs, which brought up further confusion.

That is what temperature is optimum mash pH expressed at. Now I thought this was a case closed from my "literature" research and the 5.2-5.6 range refereed to measurements made a room temperature.

However Briggs makes it clear that this is not the case and that mash pH is listed as mash temperature and any room temperature readings require a correction factor stated between 0.2-0.35.

I then googled the question only find totally differing view points and an especially interesting response to letters to BYO magazine.

https://byo.com/mr-wizard/setting-record-straight-mash-ph/

it would seem bamford, briggs and Kunze are in total disagreement with the general consensus on the internet. Have I been measuring my mash wrong all this time?

 

[hopjuice_71]

Alpha and beta amylase are optimized around a mash pH of 5.40.

With all due respect, this is not strictly true. It is the value that you will see in textbooks, review articles, and magazines. However, when you consult the primary literature it is clear that the pH ranges of barley enzymes are in fact very broad - 5.4 is really the guessed midpoint of a wide plateau that is reported as an optimal value for simplicity. Mashes will convert quite happily and efficiently outside of the 5.2-5.6 pH range we always hear about - this is in the literature but there is also a whole host of anecdotal reports on this. So, you can mess up the pH (unless you have gone totally whack with acid or base) and the mash will still work just fine. There is no guarantee the beer will turn out fine though. There was quite a debate here about how mash pH tracks to final beer flavour: https://www.homebrewtalk.com/forum/threads/ph-how-important-is-adjusting-for-ph.655119/.

 

[mabrungard]

There is no single 'optimum' pH when it comes to mashing. There are several enzymes and processes going on and each has differing pH optima. If you look at the pH vs. Temperature chart that I stole from John Palmer and posted on the Water Knowledge page of the Bru'n Water site, you'll see those multiple factors and there desirable pH ranges. There is all kinds of overlap and the other thing to recognize is that those 'optima' are not very peaky. They often work reasonably well at pHs that are a bit off the optimum pH. So don't worry too much about a certain pH being better or best.

The one thing that you should be cautious about can also be seen on that Palmer chart. Its the Proteolysis range and its enhancement at low pH. If you allow your mash pH to drop too low, you will have excessive proteolysis and you'll end up with a beer that has low body and mouthfeel. I've done it and you don't need to test out my caution.

Mashing within the 5.2 to 5.6 mash range does improve your beer. While Hopjuice is correct that your mash will still convert and you'll end up with beer, the fact is that you'll be happier with a beer that was mashed in the preferred range.

 

[specharka]

I was just going off of the chart John Palmer had in How to Brew. Apologies if I misconstrued its intent.

 

[Aristoi]

Glad you asked all these questions as it made me look into my process and I think I have been doing it wrong, or at least I am confused on the correct way to target PH. Just when I thought I was dialing in my process I am up in the air again. No intent to hijack but I think the next part could be a worthy clarification to many in a similar situation.

So I have been targeting mostly mash pH of 5.3, but I draw small sample from mash and let cool to room temp as I thought this was most accurate (not the have to use ATC) and better for the probe life. So according to BYO article and his correction on understanding ATC does this mean I should have been at pH of 5.45 instead at room temp?

I use Bru'n water spreadsheet for water and it is amazingly accurate pH predictor with how I have been checking at room temp, but I use mostly acid malt in grain bill to dial in target pH. Should I change my technique to just stick my pH probe in the mash and target 5.3 at mash temp moving forward?

Never thought I should check kettle PH burt would be curious to know the answers to OP and when to check kettle, pre or post boil or post chill again to clarify the temp question.

 

[hopjuice_71]

I was just going off of the chart John Palmer had in How to Brew. Apologies if I misconstrued its intent.
View attachment 587845

No, not a misinterpretation and the chart is not entirely incorrect. It is, however, a very stringent interpretation of the information out there. For example, there is an article published out of the Carlsberg Laboratories on the four isozymes of barley beta-amylase (Carlsberg Res. Common, vol. 52, p. 313-326, 1987). All four isozymes show >~80% activity over a pH range between 4 and nearly 7.5. For alpha amylase a nice paper shows a pH profile that has >~80% activity over a pH range between 4 and 6.5 (J. Inst. Brewing, vol 80, p. 181-187, 1973). Similar expanded ranges will be true for all of the enzymes in that chart. So, some very strict interpretations of the details have been propagated through the brewing lore. The good news, however, is that this has tended to help make more pleasant beer. So, the "real" details are not that important to know, just interesting.

 

[specharka]

Glad you asked all these questions as it made me look into my process and I think I have been doing it wrong, or at least I am confused on the correct way to target PH. Just when I thought I was dialing in my process I am up in the air again. No intent to hijack but I think the next part could be a worthy clarification to many in a similar situation.

So I have been targeting mostly mash pH of 5.3, but I draw small sample from mash and let cool to room temp as I thought this was most accurate (not the have to use ATC) and better for the probe life. So according to BYO article and his correction on understanding ATC does this mean I should have been at pH of 5.45 instead at room temp?

I use Bru'n water spreadsheet for water and it is amazingly accurate pH predictor with how I have been checking at room temp, but I use mostly acid malt in grain bill to dial in target pH. Should I change my technique to just stick my pH probe in the mash and target 5.3 at mash temp moving forward?

Never thought I should check kettle PH burt would be curious to know the answers to OP and when to check kettle, pre or post boil or post chill again to clarify the temp question.

I was so SURE of the “correct” answer until I read that article. I already knew of the 0.25-0.35 pH offset, but I had always been targeting a room temperature corrected pH vice at mash temperature. If that’s the case, I’ve been consistently mashing about 0.3 pH lower than my target, which is a statistically significant deviation.

Most of my mash pH readings have come quite close to the predicted B’runWater estimates (-0.05, +0.05), but I don’t know if that means that my target is accurate or that my mash chemistry simply follows an established model.

 

[sixhotdogneck]

There is no single 'optimum' pH when it comes to mashing. There are several enzymes and processes going on and each has differing pH optima. If you look at the pH vs. Temperature chart that I stole from John Palmer and posted on the Water Knowledge page of the Bru'n Water site, you'll see those multiple factors and there desirable pH ranges. There is all kinds of overlap and the other thing to recognize is that those 'optima' are not very peaky. They often work reasonably well at pHs that are a bit off the optimum pH. So don't worry too much about a certain pH being better or best.

The one thing that you should be cautious about can also be seen on that Palmer chart. Its the Proteolysis range and its enhancement at low pH. If you allow your mash pH to drop too low, you will have excessive proteolysis and you'll end up with a beer that has low body and mouthfeel. I've done it and you don't need to test out my caution.

Mashing within the 5.2 to 5.6 mash range does improve your beer. While Hopjuice is correct that your mash will still convert and you'll end up with beer, the fact is that you'll be happier with a beer that was mashed in the preferred range.

You'll have to qualify the excessive proteolysis with a mash pH, temperature and time. Were you purposefully doing a protein rest? A high enough temperature and short enough time those enzymes shouldn't be anything to be concerned with.

 

[mabrungard]

You'll have to qualify the excessive proteolysis with a mash pH, temperature and time. Were you purposefully doing a protein rest? A high enough temperature and short enough time those enzymes shouldn't be anything to be concerned with.

Good point.

As with modern practice, I never perform protein rests with typical malts. I was just performing a typical mash in the low 150 range for about an hour and I misjudged the acid addition and ended up with an overly low mash pH and the subsequent beer had little body or mouthfeel. I guess you are correct that you could alter other elements of the mashing program to accommodate a lower pH, but it doesn't seem worthwhile. My recommendation is to stay in a desirable pH range.

 

[Queequeg]

Wow, this thread took off. Thanks for the input from everyone who has contributed. There is a lot information to process I will have a read and undoubtedly will have questions.

 

[Queequeg]

I found a lot of useful info on Kai's site.

http://braukaiser.com/wiki/index.php/How_pH_affects_brewing