Ideal pre and post boil PH

[kingmatt]

I brewed a double IPA today shooting for the Pliny numbers posted above (5.45 mash, 5.24 pre-boil, 5.07 knockout). I adjusted my mash pH to 5.44 and my pre-boil pH to 5.25 with 85% phosphoric acid. I checked my pH at 10 minutes left in the boil and was surprised to see that it had dropped to 5.02, even with 8oz of hops.

I hit my SG dead on and had a great, compact cold break. I will post back with how the beer turns out.

 

[couchsending]

I brewed a double IPA today shooting for the Pliny numbers posted above (5.45 mash, 5.24 pre-boil, 5.07 knockout). I adjusted my mash pH to 5.44 and my pre-boil pH to 5.25 with 85% phosphoric acid. I checked my pH at 10 minutes left in the boil and was surprised to see that it had dropped to 5.02, even with 8oz of hops.

I hit my SG dead on and had a great, compact cold break. I will post back with how the beer turns out.

What was your Ca target for this beer?

Anyone know if the acid variety would cause a bigger drop in pH during the boil? Phosphoric vs. Lactic?

Not sure if this was covered in the study someone just linked but from what I’ve read recently the more Ca in the mash the more phosphates are precipitated and hence less buffer so you will get a larger pH drop during fermentation. So presumably less buffer during the boil as well? Bigger pH drop there?

 

[kingmatt]

What was your Ca target for this beer?

Anyone know if the acid variety would cause a bigger drop in pH during the boil? Phosphoric vs. Lactic?

Not sure if this was covered in the study someone just linked but from what I’ve read recently the more Ca in the mash the more phosphates are precipitated and hence less buffer so you will get a larger pH drop during fermentation. So presumably less buffer during the boil as well? Bigger pH drop there?

My target Ca was relatively high at 97 ppm.

 

[couchsending]

My target Ca was relatively high at 97 ppm.

Just adding to mash and sparge or did you add Ca salts to the kettle?

 

[kingmatt]

Mash and sparge

Just adding to mash and sparge or did you add Ca salts to the kettle?

 

[Silver_Is_Money]

That's a great resource. In Table XI we learn that:

1) For an unacidified mash at 5.73 pH the drop during the boil is 0.25 points, to 5.48 post boil and cooling
2) For a mash acidified to 5.59 pH the drop during the boil is 0.18 points, to 5.41 post boil and cooling
3) For a mash acidified to 5.40 pH the drop during the boil is 0.10 points, to 5.30 post boil and cooling
4) For a mash acidified to 5.20 pH the drop during the boil is 0.01 points, to 5.19 post boil and cooling

The more one acidifies the mash up front, the less the fall in pH witnessed during the boil, until at some juncture of early acidification there is no drop in pH during the boil.

If (as it appears) 5.2 pH is an ideal target for allowing the hops to shine, and at the juncture of 5.2 pH there is anticipated to be no further drop in pH across the span of the boil, then the process might be sitting right in front of us:

1) For the case of a mash that is anticipated to be in a state wherein mash pH will be no higher than 5.8 (or perhaps even pH 5.9) and no lower than 5.2 as measured at room temperature), do nothing to adjust the mash pH. The vast majority of beers will be found to reside within this category.
2) If the mash is anticipated to measure at above 5.8 (or perhaps even pH 5.9) or below 5.2 pH (as measured at room temperature) adjust in advance to hit (a room temperature measured) 5.5 to 5.6 pH during the mash.
3) Cool a pre-boil (fully post all stages of lautering/sparging) sample and take its pH at 20 degrees C.
4) Adjust (if necessary) to bring the Wort to pH 5.2 at this stage. Then proceed to the boil step.
5) That's it, there is no step 5, as the Wort should remain at ~5.2 pH throughout the boil, and the hops should be happy.

Thoughts on this are welcome.

 

[bierhaus15]

Sort of a mini rant and oversimplification, but IMMO, it is worth noting that much of the data on "ideal mash pH" comes from sources that were working on very different issues than what the average home brewer or IPA brewer is trying to solve for today. When Kunze and Narziss were working on this, the name of the game was making extremely clear, haze stable, and light colored pils of low gravity worts and optimizing mashes that had a very high pH due to using very pale and low-kilned, lager malts. Moreover they were largely concerned with the optimization of malt extraction-lauter efficiency, fermentability, viscosity, and achieving very low beer color. All while held to the restrictive standards of the RGB and without the use of most mash/kettle additives.

Per hopping, "smooth bitterness" is still the ideal within German brewing. When Kunze says to acidify the boil within the last 30 minutes of the boil, it is because they want to reduce isomerization - not to make the hop character shine - and ensure proper DMS removal... and ensure FAN and TSN levels provide high fermentability/pH drop using lager yeasts. That is not to say these are bad practices at all, but the reasons for doing so were not to make the best Pliny the Elder clone.

A very simple summary of German process could be to target mash pH of 5.5-5.6 (for attenution, protein break, wort viscosity, lauter effeciency and low color) with some form of lactic acid in the mash and then acidify in kettle to 5.0-5.2 for the aforementioned reasons. Final beer pH should be around 4.4-4.5.

In contrast, US/UK systems for pH control are different. Pale malts provide a higher pH drop in the mash due to kilning and the use of high Ca promotes a lower mash pH and ensures lauter pH stays constant. Compared to German process where you can see a swing in lauter pH, requiring reduction, 100-200 ppm mash Ca is normal and ensures the pH does not spike and the boil is at a relatively constant pH; 5.2-5.4. Bitterness is not a huge issue either, given the varieties used, and cultural tolerances for bitterness and hop character. Kettle pH reductions can be up to 0.3 pH, as Bamforth states, and is not uncommon. Final beer pH is lower, 4.0-4.4. Add in 5-10+% caramel/specialty malts and people often say, "what bitterness."

 

[dmtaylor]

This goes against everything I’ve ever read. Higher pH in the mash will more likely lead to astringency.

What if... everything you've ever read is wrong?!:

https://www.homebrewtalk.com/forum/threads/will-it-mash-at-ph-5-00.667992/page-2#post-8653242

 

[brewbama]

What if... everything you've ever read is wrong?!:

There’s a whole lotta truth there.

The same ideas useful for one condition gets repeated often enough until it become the best practice for every condition.

Given your system, processes, recipe, water, equipment profile, mash schedule, etc, etc you could produce results contrary to what someone else experienced using a completely different set of variables.

Measure for yourself.

 

[couchsending]

What if... everything you've ever read is wrong?!:

https://www.homebrewtalk.com/forum/threads/will-it-mash-at-ph-5-00.667992/page-2#post-8653242

It’s not.

 

[hopjuice_71]

Kettle pH reductions can be up to 0.3 pH, as Bamforth states, and is not uncommon. Final beer pH is lower, 5.0-5.4. Add in 5-10+% caramel/specialty malts and people often say, "what bitterness."

Just for clarification, did you mean 4.0-4.4?

 

[bierhaus15]

Just for clarification, did you mean 4.0-4.4?

Oops, yes.

 

[Clyde McCoy]

I don’t think you’ll find consensus on this anywhere. I’d suggest brewing the same beer twice, one with pre boil pH starting around 5.4 and one starting at say 5.0 and see what the difference is.

I’ve done a lot of digging on this topic and found plenty of info and opinions for sure but never performed the test myself.

On beers with Pilsner malt I always aim for a higher boil pH. I boil at low temps due to elevation so DMS is a bigger issue for me than if I was at sea level. The half life of the DMS precursor is twice as long at 200* compared to 212. A low boil pH lengthens that time even more. 5.4-5.5 Is what I shoot for. Plus I think with such soft water profiles the higher pH helps with a sharper bitterness especially when using lower alpha hops like say Saaz for all additions. Just make sure to lower close to 5.2/5.0 for the last 10 of the boil.

If not using Pilsner malt and in hoppy beers I’ll shoot for closer to 5.2 or potentially even lower at the start (depending on the style). Also make sure you adjust at the end. Especially with hoppy beers the hops increase pH or prevent the natural pH drop that occurs during boiling if you’re adding a lot of hops to the kettle.

There’s a line in Phil Markowski’s book on Saisons where Yvan De Baets chastised Orval for lowering their pH in the boil from 5.4 to 5.0. He said it changed the beer and reduced the bitterness too much. He likes his bitter beers.

There’s a photo of a brew log you can find online for Pliny. Start of the boil pH is 5.24, end is 5.07. Mash pH is 5.45. Acid additions are used after mash and at end of the boil.

Heard Chad Yakobsen talk about making sure KO pH is 4.9-5.1 for all beers.

Heard Henry from Monkish talk about making sure KO pH is close to 5.0 for highly hopped beers.

Most lager brewing texts talk about KO pH needs to be 5.2-5.0.

Yeast supposedly will reach a certain pH regardless of its starting value (I have not tested this either) but the premise behind adding acid to lower the pH of the wort is so the yeast can get to that lower pH faster so you have a quicker start to fermentation and an overall healthier ferment. Don’t quote me on that, someone smarter should probably chime in on this (or all of it).

Following up on this,

My understanding is that you want a mash pH of 5.2–5.4 to maximize the activity of the amylases responsible for saccharification and liquification. John Kimmich suggests a pH of 5.1-5.3 at mash temperature, which isn't far off 5.2-5.4 measured at 68F.

In terms of pre-boil pH, again a pH of 5.2-5.4 seems desirable, as much lower than that, and you'll reduce hop utilization, but much higher and the hop utilization increases, but the bitterness is harsher.

Based on the brewers you're quoting, it seems that an end of boil pH of 5.0-5.2 promotes fermentation.

Somewhat related,

Here's a photo of the pH meter at Hill Farmstead where it reads pH 5.16 https://brewbokeh.com/images/place-hillfarmstead19.jpg

And here at 1:34, you can see Shaun Hill tasting what I presume is the sweet wort (?) (near mash temperature?); the meter reads pH 5.19

 

[dmtaylor]

And here at 1:34, you can see Shaun Hill tasting what I presume is the sweet wort (?) (near mash temperature?); the meter reads pH 5.19

Presume anything you want. Everybody else does.

 

[Clyde McCoy]

Presume anything you want. Everybody else does.

No need for the saucy attitude, chief. Presume was followed by not one, but two question marks.

Finished beer is far lower pH. Hopped wort tastes terrible. What do you think he's tasting?

 

[dmtaylor]

Finished beer is far lower pH. Hopped wort tastes terrible. What do you think he's tasting?

I'm not really sure. It seems likely that it is raw wort since the pH isn't mid 4's, but that's only a guess. More importantly, we have no idea what temperature it is.

And if you think that's saucy, you ain't seen nothing. In real life I'm a fairly huggable guy. Hugs to you.

 

[Dgallo]

I'm not really sure. It seems likely that it is raw wort since the pH isn't mid 4's, but that's only a guess. More importantly, we have no idea what temperature it is.

And if you think that's saucy, you ain't seen nothing. In real life I'm a fairly huggable guy. Hugs to you.

You seem like a good hugger to me... just saying

 

[couchsending]

In terms of pre-boil pH, again a pH of 5.2-5.4 seems desirable, as much lower than that, and you'll reduce hop utilization, but much higher and the hop utilization increases, but the bitterness is harsher.

A boil pH around 5.4 makes sense if you’re trying to maximize IBUs from a certain amount of hops... however if we’re talking modern hoppy beer that is dry hopped (often at excessive levels) then there are so many other variables at play when it comes to bitterness or the perception of bitterness.

I don’t think you can draw anything from those videos or photos. There is an old Pro Brewer post where Shaun says that pre and post boil pH are the most important... however who knows if he still feels that way or not. He did say they dumped an insane amount of beer when they expanded and that he had to relearn everything he thought he knew about brewing....

If you’re adjusting at different times throughout the process I personally think that room temp mash pH anywhere from 5.3 to 5.5 is fine. Lower might be better but again that depends on so many other variables like grain bill, water chemistry, process, equipment, etc etc etc.

 

[Silver_Is_Money]

The real key is to adjust whereby to have post boil and cooling (and thereby room temperature measured) Wort pH sitting at around 5.1 to 5.2 heading into fermentation. Some even say 5.0 pH here. That makes the range of acceptability 5.0 to 5.2 pH.

 

[Clyde McCoy]

I'm not really sure. It seems likely that it is raw wort since the pH isn't mid 4's, but that's only a guess. More importantly, we have no idea what temperature it is.

The pH meter he's using is an OAKTON Economy pH 11 (confusing name). The bottom number indicates the temperature.

As far as I can tell,

Photo: pH 5.16, temp 19.8C
Video: pH 5.19, temp 27.9C

We don't know what he's tasting, so these numbers are of limited value, but perhaps these give some insight into the process of someone who is very secretive about techniques. I do find it curious that the two values are so similar.

 

[Clyde McCoy]

I don’t think you can draw anything from those videos or photos. There is an old Pro Brewer post where Shaun says that pre and post boil pH are the most important... however who knows if he still feels that way or not. He did say they dumped an insane amount of beer when they expanded and that he had to relearn everything he thought he knew about brewing....

Great tip about the Pro Brewer forum, the relevant post you mentioned:

Q: How many of you check wort, beer pH?

Shaun Hill: "Every beer I brew. Constant surveillance on brew day throughout production. Especially pre and post boil. What is the alkalinity of your water? If you're using RO, probably not as necessary..."

Shaun has other revealing posts about using 35% malted oats in one beer, US-05 yeast in several, etc.

See posts here: https://discussions.probrewer.com/member.php?3029-grassrootsvt

 

[Big Monk]

Great tip about the Pro Brewer forum, the relevant post you mentioned:

Q: How many of you check wort, beer pH?

Shaun Hill: "Every beer I brew. Constant surveillance on brew day throughout production. Especially pre and post boil. What is the alkalinity of your water? If you're using RO, probably not as necessary..."

Shaun has other revealing posts about using 35% malted oats in one beer, US-05 yeast in several, etc.

See posts here: https://discussions.probrewer.com/member.php?3029-grassrootsvt

I’m very disappointed your avatar is not the famous Wah Wah pedal that bears your name.

We need to work on that.

 

[Clyde McCoy]

I’m very disappointed your avatar is not the famous Wah Wah pedal that bears your name.

We need to work on that.

fixed

 

[Big Monk]

fixed

That’s what I’m talking about!

 

[ShaLaH]

I'm resurrecting this post since this topic has become relevant to me and there's great info in here. In regards to boil ph, are you all pulling a ph sample at the start of the boil, cooling it down to room temp, then adjusting ph if necessary?

For Post Boil or KO ph, does it matter when you acidify to lower ph? Prior to chilling or after?

My process has been this: After boil is done, I chill the wort and transfer to the fermenter. Since the wort is at room temp, I'll pull a sample now and then acidify to the desired ph before pitching yeast.

 

[Brooothru]

A very simple summary of German process could be to target mash pH of 5.5-5.6 (for attenution, protein break, wort viscosity, lauter effeciency and low color) with some form of lactic acid in the mash and then acidify in kettle to 5.0-5.2 for the aforementioned reasons. Final beer pH should be around 4.4-4.5.

Very good information, and is exactly the guidance I was looking for several months ago when I was brewing my (mostly) German lagers for winter time storage. As luck would have it, I settled on a process that would target pH 5.4-5.6 in the mash, and then acidify to a target of 5.0-5.2 for the boil. I was able to hit those marks and am getting ready to to tap the first keg that's been lagering since October, as soon as either my Blonde ale or IPA kicks, which should be soon. I'm curious to see if the finished beer pH has actually dropped to the mid 4.4-4.5 range.

I also targeted 5.4-5.6 mash and 5.0-5.2 boil pH values for the ales. I'm curious what affect highly hopped beers have on pH since supposedly lots of hops = higher alkalinity. I've been monitoring pH at different stages (mash, ferment, finished), rather than just mash, since last summer and didn't notice more than 0.1~0.2 pH decrease in the finished beer from ~5.1 post-boil/pre-ferment. They were pales and IPAs and I would expect them to drop less than the lightly hopped lagers. The lagers were all in the 50-100 Ca ppm range, and the ales were 150~200 Ca ppm, in addition to higher sulfate and Cl/SO4 ratios.

I only wish I had realized in High School and college how interesting and useful chemistry is!

 

[Silver_Is_Money]

The general consensus is that so called lager yeast (I prefer to label it as cold fermenting yeast) will finish fermenting at pH's in the 4.3-4.6 range, and ale (warm fermenting) yeasts will finish in the 3.9-4.3 pH range. I believe that most have attributed this to the yeast, but there may be a different reason. Pilsners and other lagers are often acidified with organic acids such as Lactic Acid, Acid Malt, or Sauergut, with all of these being in the end Lactic Acid. Lactic Acid increases the buffering capacity of the Wort. Ales are often acidified with mineral acids such as Phosphoric Acid, CRS (AMS), HCl, or Sulfuric Acid, and these do not increase the buffering capacity of the Wort. It may be that (at least in part) the increased buffering induced via Lactic Acid impedes the yeasts ability to lower the pH during fermentation.

 

[Brooothru]

The general consensus is that so called lager yeast (I prefer to label it as cold fermenting yeast) will finish fermenting at pH's in the 4.3-4.6 range, and ale (warm fermenting) yeasts will finish in the 3.9-4.3 pH range. I believe that most have attributed this to the yeast, but there may be a different reason. Pilsners and other lagers are often acidified with organic acids such as Lactic Acid, Acid Malt, or Sauergut, with all of these being in the end Lactic Acid. Lactic Acid increases the buffering capacity of the Wort. Ales are often acidified with mineral acids such as Phosphoric Acid, CRS (AMS), HCl, or Sulfuric Acid, and these do not increase the buffering capacity of the Wort. It may be that (at least in part) the increased buffering induced via Lactic Acid impedes the yeasts ability to lower the pH during fermentation.

So, given those data, I shouldn't be surprised if/that the pH values of my finished ales and lagers are relatively close. ("close" and "relative" being, well, 'relative', since pH is a Log scale measurement).

 

[Silver_Is_Money]

So, given those data, I shouldn't be surprised if/that the pH values of my finished ales and lagers are relatively close. ("close" and "relative" being, well, 'relative', since pH is a Log scale measurement).

If they are close, it would lend credence to the organic acid vs. mineral acid theory, and if they are not, it will provide evidence against the theory. All theories are only as good as the verification or negation of them by real world testing.

 

[Silver_Is_Money]

So, given those data, I shouldn't be surprised if/that the pH values of my finished ales and lagers are relatively close. ("close" and "relative" being, well, 'relative', since pH is a Log scale measurement).

Here is some relevant scientific evidence backing my speculation as seen in post #67 above:

The regression analyses suggested that the buffering capacity of wort linearly increased with an increase in the level of organic acids,including acetic acid, lactic acid, citric acid, succinic acid, furmaric acid and pyruvic acid in wort.

Organic acids contributed substantially to the buffering capacity of wort.

Phosphate, which has been said to be responsible for some of the buffering capacity of wort, was found to be an ineffective buffer at the pH of wort.

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/jib.286

Thus lactic acid additions to wort substantially contribute to increasing the initial buffering capacity, and phosphoric acid additions to the wort do not.

 

[Silver_Is_Money]

Expanded quote from the above web linked peer reviewed dissertation:

Phosphate was added into a wort with a buffering capacity of 1.645, according to the concentrations of 100, 300, 500 and 700 mg/L; then the buffering capacity of the wort after the addition of phosphate was determined. The results were 1.615, 1.647, 1.636 and 1.679, respectively, when the concentrations of phosphate added were 100, 300, 500 and 700 mg/L, respectively. It can be inferred that phosphate, which has been said to be responsible for some of the buffering capacity of wort, is not an effective buffer at the pH of wort.

This study used log based buffering capacities, as is typical of commercial brewing level buffering applications. To convert to terms such as I have used requires the following:

10^1.645 = 44.16 mEq/Kg_pH

Thus when the study concluded that:

The regression analyses suggested that the buffering capacity of wort linearly increased with an increase in the level of organic acids,including acetic acid, lactic acid, citric acid, succinic acid, furmaric acid and pyruvic acid in wort.

The linearity of the noted buffering coefficient increase was plotted on a log scale, and as such it was actually log base 10 exponential.

 

[Silver_Is_Money]

If you ever wondered why many on this forum have discovered via pH meter testing that a popular commercial/retail phosphate salts based "buffering" product is not likely to stabilize a wort at pH "5.2" during the mash, the above is the reason.

Thus all of the literature and books of the past which express the view that phosphate is the main buffering contributor to wort are wrong. Quoting @dmtaylor from above in post #48:

What if... everything you've ever read is wrong?!

 

[Silver_Is_Money]

If phosphates are not the primary buffering compounds found within wort, what actual compounds are?

The effective buffers in wort are carboxylic acid groups, related to glutamate and aspartate, peptides/ poly-peptides containing glutamate and aspartate, and organic acids (e.g., citrate).

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/j.2050-0416.1997.tb00932.x

 

[Brooothru]

If phosphates are not the primary buffering compounds found within wort, what actual compounds are?

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/j.2050-0416.1997.tb00932.x

Excellent summations, Professor!

This forum never fails to provide the explanations of qualifiable and quantifiable data points at the juncture of science and the art of brewing beer. The more I learn, the more I want to learn.

 

[Silver_Is_Money]

AJ deLange alternately quantified this "increasing wort buffer with the addition of lactic acid, or organic or weak acids in general" phenomenon differently, as to the relative "acid strength" of lactic acid (etc..., I.E., for weak organic acids in general) decreasing as wort pH falls [and in 'lock step' math-model relation to each acids molecular Ka or pKa based H+ ion (or proton, as AJ calls it) release dissociation constant(s)]. It appears that one can either look at this observed and documented and quantified phenomenon in terms of decreasing acid strength as per AJ, or as a 'linear' (albeit log base 10 linear) function of increasing wort buffering capacity with the addition of ever more and more of an organic or 'weak' acid, but one should never attempt to apply both methods simultaneously, as applying both methods at one time would amount to what is commonly referred to as "double dipping".

 

[Brooothru]

I'd never thought of the process as decreasing the buffering as opposed to increasing the acidity, but clearly either is a valid point of view (i.e., glass half full or half empty) but without the imprimatur of optimism or pessimism. Indeed, isn't the mathematical notation of logarithms actually a negative log to a negative exponential, thus annotated as a positive value? I'm probably wrong about this, but it's been more than 5 decades since high school math and I probably had it messed up back then as well.

The "double dipping" metaphor, however, is spot on and much easier to grasp.

 

[Silver_Is_Money]

I clearly struggle with logarithms as well, and that's why I created this almost forgotten (even by me) linked thread:

Miscellaneous ramblings with regard to Buffering Capacity (BC) expressed as mEq/Kg_pH vs. as a log (base 10)

Note of disclaimer: All of the following is mere speculation on my part pending verification, and I welcome independent verification and/or comment by my peers and superiors. Being mere speculation it is certainly open to being incorrect thinking in part or in total, but I'm tossing my...

www.homebrewtalk.com

I pretty much laid my soul bare for all to see in that thread. I accordingly asked for help throughout, but never got any.

 

[VirginiaHops1]

Great tip about the Pro Brewer forum, the relevant post you mentioned:

Q: How many of you check wort, beer pH?

Shaun Hill: "Every beer I brew. Constant surveillance on brew day throughout production. Especially pre and post boil. What is the alkalinity of your water? If you're using RO, probably not as necessary..."

Shaun has other revealing posts about using 35% malted oats in one beer, US-05 yeast in several, etc.

See posts here: User Profile - ProBrewer Discussion Board

Also the post circa 2010(when Hill Farmstead opened) where he highly recommends WLP510(belgian) in response to someone asking for a belgian yeast to experiment with in non-belgian styles like pale ales