Ideal pre and post boil PH

[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.

 

[Broothru]

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.

 

[Broothru]

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

 

[Broothru]

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".

 

[Broothru]

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:

https://www.homebrewtalk.com/thread...ssed-as-meq-kg_ph-vs-as-a-log-base-10.686617/
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

 

[Unicorn_Platypus]

A few conflicting considerations. Actually a higher pH, toward 5.5, gives better break coagulation. But the lower end does produce a much smoother hop bitterness, though at the expense of efficient utilization (less but more pleasant bitterness.) And if you're using kettle finings like Irish moss or Whirlfloc, these are really only effective between pH 5.0 and 5.2. Below that wort fails to fine at all, above that it's much less effective. So a strategy many brewers use is to aim for a preboil pH of 5.4-5.5, and acidify to 5.0-5.2 before adding Whirlfloc. The lower pH of the chilled wort is also beneficial to fermentation for various reasons. But @Dgallo's advice is sound. 5.2-5.5 is a good compromise, and if you have his ~100ppm Ca, you can expect the wort pH to drop by up to 0.2 during the boil, helping you to maximize all these goals in the compromise.

Great info! A few follow up questions for folks


1) for a hoppy beer, if the late boil adjustments are made to ~5.0 to ~5.2 with whirfloc, but are done prior to a large hopstand... Is it recommended to add more acid post whirlpool to ensure you are still in that range? Thinking a decent strategy could be to aim for a single addition to hit 5.0 with whirlfloc and figure the whirlpool kicks PH back up to 5.1 ish

2) Thoughts on ideal preboil & post boil PH for a stout? My current practice is to Mash at 5.5 for darker color beers to avoid acrid roasty character

 

[whattabrau]

2) Thoughts on ideal preboil & post boil PH for a stout? My current practice is to Mash at 5.5 for darker color beers to avoid acrid roasty character

For almost all beers I target the mash at 5.5 and drop the kettle pH to around 5.2 -- I've never understood why you should use mash pH to fully determine wort pH. There are some exceptions to the kettle pH such as with Voss kveik. If I'm going for a very pale beer, I might drop the kettle pH preboil, but for most I do it at 10min. Can't really say I "take advantage" of the better hop utilization at a higher pH, but the 10min is a habit, and it gives me enough time to measure the boil pH before and after acidification and react if necessary.

Specifically for dry stouts, I try to get a bunch of lactic acid in there, given how Guinness is supposedly a blend of a small amount of sour beer. I acknowledge that pouring in lactic acid by the scoop to neutralize my water's alkalinity (5+mEq/L) might lead to a higher beer pH, but I'm going for a) 5.2 pH for a good kettle break b) the flavor. Given that my beer lives in relatively cool and dark conditions for its entire lifespan, I'm not overly concerned with shorter shelf life due to slightly elevated beer pH.

 

[jambop]

I’ve never seen pH fall .3 during any of my 90 minute boils.

Me neither I have seen usually a drop of 0.1-0.2 over a 90 min boil using my Grainfather kit. However pH for me is very misleading for mash liquor, I only go by alkalinity which varies depending on beer type but I am of the opinion that if you get the alkalinity of your brew liquor right you can forget all about pH. each to their own as they say.

 

[Unicorn_Platypus]

Me neither I have seen usually a drop of 0.1-0.2 over a 90 min boil using my Grainfather kit. However pH for me is very misleading for mash liquor, I only go by alkalinity which varies depending on beer type but I am of the opinion that if you get the alkalinity of your brew liquor right you can forget all about pH. each to their own as they say.

I agree about alkalinity of brew liquor before you mash in, but doesn't the PH reading after mashing matter and then making adjustments in the boil etc become relevant?

In other words the alkalinity of strike water impacts the mash PH. But after the mash is done the alkalinity becomes less relevant as everything has already been buffered

The starting PH of the strik water isn't as essential as the Alkalinity though I agree

Although I'm not a chemist and rely on Bru'n water. Bru'n water tends to not really care as much about strike water PH as alkalinity as far as I can tell

 

[jambop]

I agree about alkalinity of brew liquor before you mash in, but doesn't the PH reading after mashing matter and then making adjustments in the boil etc become relevant?

In other words the alkalinity of strike water impacts the mash PH. But after the mash is done the alkalinity becomes less relevant as everything has already been buffered

The starting PH of the strik water isn't as essential as the Alkalinity though I agree

Although I'm not a chemist and rely on Bru'n water. Bru'n water tends to not really care as much about strike water PH as alkalinity as far as I can tell

I maybe could have explained my brew liquor better. I use a water calculator as well
Firstly I make my brew liquor at the correct alkalinity for the mash but I also add Calcium and magnesium salts to get the correct balance for my chosen beer style of course these salts also add Sulphate and Chloride. After mashing is over I sparge with liquor that is only adjusted to the correct alkalinity and add the salts directly to the boiler.
If we look at the great brewing nation Germany, much revered on this site as far as I can see, they get by with only malt, hops, yeast and water ... I think if you can make a brewing liquor to mimic the approximate ionic characteristics of those of a chosen beer style eg. English Bitter, German Lager or Czech Pilsner pH and meters are not needed . However the Hi-Fi brewer must have his day

 

[Unicorn_Platypus]

I maybe could have explained my brew liquor better. I use a water calculator as well
Firstly I make my brew liquor at the correct alkalinity for the mash but I also add Calcium and magnesium salts to get the correct balance for my chosen beer style of course these salts also add Sulphate and Chloride. After mashing is over I sparge with liquor that is only adjusted to the correct alkalinity and add the salts directly to the boiler.
If we look at the great brewing nation Germany, much revered on this site as far as I can see, they get by with only malt, hops, yeast and water ... I think if you can make a brewing liquor to mimic the approximate ionic characteristics of those of a chosen beer style eg. English Bitter, German Lager or Czech Pilsner pH and meters are not needed . However the Hi-Fi brewer must have his day

My understanding is that Germans use Sauergut to adjust post boil PH & acidulated malt to adjust Mash PH which abide by the Reinheitsgebot. What matters in the end though is how your beers taste. If your process is working and you are happy with the results, no need to rock the boat.

http://www.germanbrewing.net/docs/On_Brewing_Bavarian_Helles_v3.pdf

 

[jambop]

My understanding is that Germans use Sauergut to adjust post boil PH & acidulated malt to adjust Mash PH which abide by the Reinheitsgebot. What matters in the end though is how your beers taste. If your process is working and you are happy with the results, no need to rock the boat.

http://www.germanbrewing.net/docs/On_Brewing_Bavarian_Helles_v3.pdf

I knew they used acid malt but was unaware of the cultured lactic acid wort. The German brewers certainly used their collective brains to get around some of the hurdles posed by the beer law.

 

[mac_1103]

I think the point is that if you adjust the water chemistry correctly the pH will be what it's supposed to be, right? Saying that you don't need a pH meter is not the same as saying that pH doesn't matter.

 

[Unicorn_Platypus]

I think the point is that if you adjust the water chemistry correctly the pH will be what it's supposed to be, right? Say that you don't need a pH meter is not the same as saying that pH doesn't matter.

I generally agree that you can rely on calculators to dial in your mash PH for lighter colored beers empirically without a meter. I did this for years and my lighter colored beers were still great.

However for darker beers due to greater variability in how the roasted grains effect PH, I didn't start brewing great ones until I got a PH meter. So far years, I just stuck to lighter styles.

More recently, I've been fine tuning and gotten into making acid adjustments after the boil and after dry hopping. For the post fermentation dry hops adjustments you could rely on taste and a calculator so a PH meter isn't as crucial. For the post boil adjustments its a little more crucial.

Also, I like having the PH meter to take notes on where beers ended up so I have it for future reference and can adjust if I didn't hit a target, or if I feel that target left something to be desired.

I cannot recommend enough using lactic acid at dry hopping (especially large dry hops) to bring the PH down. I've found this greatly combats hop burn and the acidity helps the citrus and tropical flavors of the hops pop. I've seen PH increase as much as 0.1 from a large dry hop

Adjusting boil PH is a little newer to me which is why I've started following this thread

 

[mac_1103]

Of course, saying that you don't NEED a pH meter is also not the same as saying that pH meters are useless.

 

[jambop]

"I think the point is that if you adjust the water chemistry correctly the pH will be what it's supposed to be, right? Saying that you don't need a pH meter is not the same as saying that pH doesn't matter."

I don't think anybody did say pH does not matter and what is the right pH ? The correct pH is going to fall into a pH range. Using alkalinity you can hit that range without knowing the pH of your brewing liquor

Of course, saying that you don't NEED a pH meter is also not the same as saying that pH meters are useless.

Beer must have been awful before pH meters came along... eh no actually. For the avoidance of doubt I never said pH meters were useless or pH does not matter. Rather I made the point that if you have the alkalinity of your brewing liquor right a pH meter is not really needed your mash will be in the right pH range. If I had the choice between a pH meter or an alkalinity testing kit I would take the testing kit it tells you more about you brewing liquor than a pH meter does at the most important point of the brewing process.... before you start to do anything . I do have a pH meter I definitely have no reliance on it though. As I said each to their own.

 

[VikeMan]

I agree the starting point should not be mash liquor pH, which is essentially irrelevant. But mash liquor total alkalinity also is not enough information by itself. The reason is that Calcium and Magnesium in the water also affect mash pH. As an example, you could have two different waters with 100 ppm Total Alkalinity as HCO3, as follows (ppm). I'm omitting other balancing ions for clarity:

Water 1...
Ca: 10
Mg: 1
Alkalinity as HCO3: 100

Water 2...
Ca: 100
Mg: 10
Alkalinity as HCO3: 100

With a given grain bill, these two waters will result in very different mash pH. There's no getting around it. If you want to be able to predict mash pH (and adjust accordingly) for a given grain bill, you need to know Calcium, Magnesium, and Total Alkalinity.

Now, you can learn from experience how to adjust alkalinity to hit "within range" mash pH with various grain bills and your water. But for someone with substantially different water (even if is has the same total alkalinity as yours), your hard earned data/method (i.e. adjust alkalinity down to "X") will not work.