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General Category => All Grain Brewing => Topic started by: narcout on August 04, 2012, 10:50:50 PM

Title: Shift in thought regarding optimal mash pH
Post by: narcout on August 04, 2012, 10:50:50 PM
Note: all pH measurements referenced in the below post are room temperature measurements.

In How to Brew, Palmer states that the goal is to hit a mash pH of between 5.4 and 5.8.

However, I've read a lot of posts on this forum where people state their target mash pH is 5.3.  I've also read some posts where it has been posited that a mash pH higher than 5.6 can cause problems - regardless of the style of beer being brewed.

Has there been a recent shift in thought concerning optimal mash pH?
Title: Re: Shift in thought regarding optimal mash pH
Post by: nateo on August 04, 2012, 11:22:35 PM
The short answer is there is no "optimal" mash pH.

Have you seen this: http://braukaiser.com/wiki/index.php?title=How_pH_affects_brewing

"A commonly accepted optimal range for mash pH is 5.2 - 5.7 with 5.5 being optimal for starch conversion activity but many authors report wort and beer quality benefits if the pH is lowered into the 5.2 - 5.4 range [Kunze, 2007][Narziss, 2005]. Kunze in particular lists the following benefits for a mash pH as low as 5.2. Since it is a good and fairly comprehensive list I cited it here. Some of these benefits listed will be explained in the following sections [Kunze, 2007]:"

I know a lot of people love John Palmer, but I think a lot of his advice is a bit off.
Title: Re: Shift in thought regarding optimal mash pH
Post by: tom on August 05, 2012, 12:29:03 AM
And they don't always mention whether the mash pH was measured at room temperature or mash temperature.

The higher mash temperature can lower the pH by 0.3 pH.  So 5.4 to 5.8 at room temperature is actually 5.1 to 5.5 at mash temperature.
Title: Re: Shift in thought regarding optimal mash pH
Post by: positiverpr on August 05, 2012, 06:56:39 PM
sierra nevada mashes at 5.2 from what i've read. i'll trust that they've done their homework on outcomes from hitting that number.
Title: Re: Shift in thought regarding optimal mash pH
Post by: nateo on August 05, 2012, 07:27:12 PM
sierra nevada mashes at 5.2 from what i've read. i'll trust that they've done their homework on outcomes from hitting that number.

That makes sense. Their brewhouse is German and Kunze says there are a lot of benefits to mashing at 5.2.
Title: Re: Shift in thought regarding optimal mash pH
Post by: narvin on August 05, 2012, 10:44:47 PM
sierra nevada mashes at 5.2 from what i've read. i'll trust that they've done their homework on outcomes from hitting that number.

Is this at mash temp?  That would be 5.4-5.5 at room temp, which is pretty typical.  I think someone (Denny?) said they measure all pH at the intended use temperature when he was talking about their water adjustments.  Please correct me if I made that up :-)

At any rate, the range for conversion is actually pretty large, so I don't think John is wrong.  In practice, I think most brewers aim for the lower end of that range for other benefits.
Title: Shift in thought regarding optimal mash pH
Post by: denny on August 05, 2012, 11:10:32 PM
I don't recall saying that, but I cool to room temp (70-75) for measuring.


Sent from my iPad using Tapatalk HD
Title: Re: Shift in thought regarding optimal mash pH
Post by: narvin on August 06, 2012, 03:10:28 AM
I don't recall saying that, but I cool to room temp (70-75) for measuring.


Looks like it was Gordon who said it.  Close enough (sorry Gordon!).

http://www.homebrewersassociation.org/forum/index.php?topic=12253.msg161096#msg161096
Title: Re: Shift in thought regarding optimal mash pH
Post by: davidgzach on August 08, 2012, 02:44:35 PM
From what I have read, all the breweries take their readings at room temp in the lab.

Dave
Title: Re: Shift in thought regarding optimal mash pH
Post by: mmitchem on August 08, 2012, 03:10:51 PM
I recently had a discussion on mash pH with alot of heavy hitters weighing in. All said that you measure mash pH at room temp. It is what the testing equipment (strips, probes)are calibrated for. The specific temperature might vary a few degrees based on the manufacturer, but still around what we all would consider room temp.
I also recall saying that which end of the optimal range your mash pH falls in will result in a slightly different flavor profile. For me that is getting pretty granular so I just try to hit 5.2-5.7 at room temp. :)
Title: Re: Shift in thought regarding optimal mash pH
Post by: narvin on August 08, 2012, 03:55:21 PM
I agree that you should cool your sample for the sake of your equipment.  Unfortunately, it doesn't seem to be a reasonable assumption that all breweries and texts quote their readings at room temp.  My impression of what Gordon said was the Sierra Nevada was either measuring or correcting their reading to be represented at mash temp. Perhaps he can add some more insight to this.
Title: Re: Shift in thought regarding optimal mash pH
Post by: denny on August 08, 2012, 04:19:24 PM
From what I have read, all the breweries take their readings at room temp in the lab.

Dave

Sierra Nevada did when I was there.
Title: Re: Shift in thought regarding optimal mash pH
Post by: Kaiser on August 08, 2012, 05:18:28 PM
For a while now I'm trying to find a commercial brewing equipment manufacturer that offers in-line pH probes. The description for that probe may show how to convert between between mash and room temp measurements.

High temp in-line pH probes do seem to exist for food processing.

Kai
Title: Re: Shift in thought regarding optimal mash pH
Post by: denny on August 08, 2012, 05:58:13 PM
I don't know how much use this will be, but here's the pH testing setup at Sierra Nevada's pilot brewery...

(http://i794.photobucket.com/albums/yy221/dennyconn/Beer%20Camp/DSCN0527.jpg)
Title: Re: Shift in thought regarding optimal mash pH
Post by: Kaiser on August 08, 2012, 06:42:20 PM
At least in my mind, and I have thought about this a lot) there is little doubt that pH measurements at room temp are standard practice. I'm curious though, if there are brewers in the industry that also have the ability to measure pH at process temp and how they correlate this with room temp pH measurements taken in the lab.

Kai
Title: Re: Shift in thought regarding optimal mash pH
Post by: narvin on August 08, 2012, 06:49:13 PM
Cool photo.  Does that say 52.5 C?
Title: Re: Shift in thought regarding optimal mash pH
Post by: euge on August 08, 2012, 06:57:16 PM
Cool photo.  Does that say 52.5 C?

52.5 degree Celsius = 126.5 degree Fahrenheit

So maybe they aren't waiting to cool it completely...

So remind me again why we measure at room temp and then do a conversion? Are pH meters significantly off at any higher or lower than room temp?
Title: Re: Shift in thought regarding optimal mash pH
Post by: CB-Illinois on August 08, 2012, 07:24:52 PM
Hi all,

I have used the pH meter Denny posted, and I can say with some certainty that the probe they are using is VERY sensitive and must be almost constantly in a buffer solution at room temp except when the probe is in the beer (and the beer must be at room temp also).

I have used probes that are designed to be much more robust and could measure solutions at high temps, but the readings were only for information (to make sure we were on track with pharmaceutical batch production).  When needed we would always cool a sample and take a reading at room temp for an actual in-process check.  I seem to remember the degree of error increasing quite a bit once a sampe was more than a few degrees above room temp.

Hope that helps.
Title: Re: Shift in thought regarding optimal mash pH
Post by: denny on August 08, 2012, 08:12:45 PM
Cool photo.  Does that say 52.5 C?

52.5 degree Celsius = 126.5 degree Fahrenheit

So maybe they aren't waiting to cool it completely...

So remind me again why we measure at room temp and then do a conversion? Are pH meters significantly off at any higher or lower than room temp?

It sat there for quite a while and I'm pretty sure that it ended up at room temp.  Mike K., you out there?  Do you recall?
Title: Re: Shift in thought regarding optimal mash pH
Post by: mrcceo on August 10, 2012, 07:03:01 PM
I know this information is specific to my probe but thought it might prove useful in regards to this thread.

"The GK733526B electrode is rated for use from 0 - 100 °C.  That does not mean is should be continuously used at that kind of elevated temperature, but if you are doing grab samples, it should not be a problem.

Accuracy should not be affected if you are using it at an elevated temperature, but you should be using a temperature sensor on your pH meter for accuracy at those temperatures, and yes, for most accuracy, you should also have your calibration standards at 68 °C when calibrating.

Also, do not expect to see the same pH readings at 68C as you do at 25C.  I am not sure how your sample will respond to that kind of temperature change, but as an example, the pH 4 calibration buffer that reads 4.005 at 25C will read 4.116 at 70C; the pH 7 buffer that reads 7.000 at 25C will read 6.982 at 70C.

If you have any other questions, please let me know.

Thank you.

Sincerely,
Tim Schmitt
Technical Support
Hach Company
Title: Re: Shift in thought regarding optimal mash pH
Post by: weithman5 on August 10, 2012, 07:43:19 PM
so over a wide range 0f 25c-70c we are off by at most 0.116?
Title: Re: Shift in thought regarding optimal mash pH
Post by: Kaiser on August 10, 2012, 07:53:04 PM
so over a wide range 0f 25c-70c we are off by at most 0.116?

The temperature dependent pH shift that we are talking about here is dependent on the solution and is likely different between the buffer solutions mentioned in above statement and mash or wort. This is why we can't compensate for them universally. Aside from the fact that they are actual changes in pH.

Kai
Title: Re: Shift in thought regarding optimal mash pH
Post by: tomsawyer on August 10, 2012, 09:48:05 PM
Also keep in mind that there is temperature compensation because of the difference in the electrical signal at different temps, and then theres temp changes in the solution that Kai is referring to.  When your meter has ATC (auto temp comp) it is only adjusting the readout based on temp.  Its not converting your reading to what it is at 68F.
Title: Re: Shift in thought regarding optimal mash pH
Post by: weithman5 on August 10, 2012, 10:09:04 PM
yes, but if the meter can handle the temperature with good repeatability, an individual could make a small correlation table between mash temp ph and at room temperature ph.
Title: Re: Shift in thought regarding optimal mash pH
Post by: nateo on August 10, 2012, 11:32:40 PM
yes, but if the meter can handle the temperature with good repeatability, an individual could make a small correlation table between mash temp ph and at room temperature ph.

I don't think so, because it depends on the composition of the solution. I assume it's also related to water chemistry and wort gravity.
Title: Re: Shift in thought regarding optimal mash pH
Post by: narvin on August 11, 2012, 12:08:32 AM
yes, but if the meter can handle the temperature with good repeatability, an individual could make a small correlation table between mash temp ph and at room temperature ph.

I don't think so, because it depends on the composition of the solution. I assume it's also related to water chemistry and wort gravity.


Well, to be fair, the pH range of enzyme activity is measured at the temperature they are active, meaning they're measured at mash pH.  So we are making this correction when we measure wort pH at room temperature.
Title: Re: Shift in thought regarding optimal mash pH
Post by: Kaiser on August 11, 2012, 02:04:14 AM
I too think that the pH over temp curve will be fairly similar between wort samples.

Kai
Title: Shift in thought regarding optimal mash pH
Post by: bluesman on August 11, 2012, 04:40:15 AM
I realize that ideal mash conditions are in the 5.2-5.7 range, but what is the real difference of a mash conducted at 5.2 vs. 5.6 in terms of beer flavor.  This would be a great experiment.  How does this effect mash efficiency or beer flavor.  I think Kai has conducted some experiments in this regard.  I've made excellent beers at both ends of the pH spectrum. Tannin extraction increases with increasing pH, but what can be said for a mash conducted on he higher side of the range?

This is an interesting mechanism that isn't clearly understood in terms of it's effect on the end product. I would like to see some further experimentation on the effects of mash pH on beer flavor.
Title: Re: Shift in thought regarding optimal mash pH
Post by: tomsawyer on August 11, 2012, 12:41:12 PM
While we're discussing pH, why is the final pH of wheaqt beer so much loer than all-barley beer in spite of both starting at a similar mash pH?
Title: Re: Re: Shift in thought regarding optimal mash pH
Post by: Kaiser on August 11, 2012, 01:40:55 PM
While we're discussing pH, why is the final pH of wheaqt beer so much loer than all-barley beer in spite of both starting at a similar mash pH?

The more aggressive fermentation leads to a faster and larger pH drop. You can also observe this with different pitching rates: http://braukaiser.com/blog/blog/2012/06/21/pitching-rate-experiment-tasting/ look at pH over pitching rate.

Kai
Title: Re: Shift in thought regarding optimal mash pH
Post by: mabrungard on August 11, 2012, 01:58:29 PM
While we're discussing pH, why is the final pH of wheaqt beer so much loer than all-barley beer in spite of both starting at a similar mash pH?

Its less a factor of the mash or wort pH and more a factor of the yeast.  Some yeast produce more acids which results in a more acidic beer.  Weizen yeast has a number of factors that are quite different from other yeasts.
Title: Re: Shift in thought regarding optimal mash pH
Post by: nateo on August 11, 2012, 02:40:21 PM
Its less a factor of the mash or wort pH and more a factor of the yeast.  Some yeast produce more acids which results in a more acidic beer.  Weizen yeast has a number of factors that are quite different from other yeasts.

I've noticed the same thing with wine yeasts. Some are dramatically more acidic than others, even when fermenting in the exact same must.
Title: Re: Shift in thought regarding optimal mash pH
Post by: tomsawyer on August 13, 2012, 06:49:45 PM
While we're discussing pH, why is the final pH of wheaqt beer so much loer than all-barley beer in spite of both starting at a similar mash pH?

Its less a factor of the mash or wort pH and more a factor of the yeast.  Some yeast produce more acids which results in a more acidic beer.  Weizen yeast has a number of factors that are quite different from other yeasts.
Interesting, do we know what organic acids are produced in greater abundance?  I suppose its citric, malic or lactic.  If it were mostly malic I could maybe do malolactic fermentation on my wheat beer like I do for red wine.  Given the description of a citric character, I would have to guess citric acid although malic has a pretty tart character as well.  Then theres the ferrulic acid possibility which is found at higher levels in wheat, but is decarboxylated by the yeast and is no longer an acid once converted.
Title: Re: Shift in thought regarding optimal mash pH
Post by: tomsawyer on August 13, 2012, 06:57:07 PM
Its less a factor of the mash or wort pH and more a factor of the yeast.  Some yeast produce more acids which results in a more acidic beer.  Weizen yeast has a number of factors that are quite different from other yeasts.

I've noticed the same thing with wine yeasts. Some are dramatically more acidic than others, even when fermenting in the exact same must.
I haven't heard of this before, which ones do you think produce more acid?
Title: Re: Shift in thought regarding optimal mash pH
Post by: nateo on August 13, 2012, 08:11:49 PM
I haven't heard of this before, which ones do you think produce more acid?

In my mead fermentation trials, RC 212 lowered the pH much more than the others. The pH for Cote des Blanc was a little higher, K1V was higher still, and 71B and Premier Cuvee tied for the highest pH.
Title: Re: Shift in thought regarding optimal mash pH
Post by: mabrungard on August 13, 2012, 08:45:21 PM
At the seminar on Berliner Weisse at this summer's AHA National Convention, the presenter pointed out that the Wyeast 1007 produced a larger pH drop than other yeasts evaluated.  Obviously this result is only qualitative and not quantitative, but its a data point for your reference.
Title: Re: Shift in thought regarding optimal mash pH
Post by: Kaiser on August 13, 2012, 08:46:58 PM
To a large extent it is not the secretion of a given acid by yeast but its ability to pump protons (H+) into the surrounding beer during fermentation. This lowers the beer pH and the resulting pH gradient between beer and yeast aids the yeast's nutrient uptake.

Kai
Title: Re: Shift in thought regarding optimal mash pH
Post by: tomsawyer on August 13, 2012, 09:13:13 PM
To a large extent it is not the secretion of a given acid by yeast but its ability to pump protons (H+) into the surrounding beer during fermentation. This lowers the beer pH and the resulting pH gradient between beer and yeast aids the yeast's nutrient uptake.

Kai

Maybe but I don't think you can taste hydrogen ions at a low concentration.  Soda pop doesn't taste tart and its pH is on par with wheat beer.  If you are tasting something tart its an organic acid or its salt.  So I'm guessing theres something tart produced either by the yeast or from the wheat.  Since you don't expect a lower mash pH just from using wheat, it must be something produced during fermentation.

Now maybe its simply that the pH of wheat beer is what it is, and has nothing to do with an organic acid that is also present and giving the tartness.  It would just seem convenient to think that an organic acid at detectable levels, is also contributing to the low pH.
Title: Re: Shift in thought regarding optimal mash pH
Post by: tomsawyer on August 13, 2012, 09:15:31 PM
At the seminar on Berliner Weisse at this summer's AHA National Convention, the presenter pointed out that the Wyeast 1007 produced a larger pH drop than other yeasts evaluated.  Obviously this result is only qualitative and not quantitative, but its a data point for your reference.
Odd, I've never thought of altbier as being acidic or at least not tart.  This may suggest that the two (pH and tartness) are not necessarily tied to one another.
Title: Re: Shift in thought regarding optimal mash pH
Post by: tomsawyer on August 13, 2012, 09:17:31 PM
I did recently make a wheat beer with WY1056 and it was initially one of the sweetest most lovely American wheat beers I ever made.  One keg seemed to get tart after a few weeks of storage (during which time we drank the first keg) but this may have been from a minor infection.
Title: Re: Shift in thought regarding optimal mash pH
Post by: morticaixavier on August 13, 2012, 10:43:34 PM
[...]  Soda pop doesn't taste tart and its pH is on par with wheat beer.  [...]

to be fair soda pop is packed with sugars and sweet will disguise tart just as it disguises bitter.
Title: Re: Shift in thought regarding optimal mash pH
Post by: tomsawyer on August 13, 2012, 11:20:02 PM
[...]  Soda pop doesn't taste tart and its pH is on par with wheat beer.  [...]

to be fair soda pop is packed with sugars and sweet will disguise tart just as it disguises bitter.

OK then think about how smooth a dry red wine can taste at a pH of 3.7.  Its likely gone through MLF to convert the tarter malic to less tart lactic acid.
Title: Re: Shift in thought regarding optimal mash pH
Post by: Kaiser on August 14, 2012, 01:49:49 AM
Soda pop doesn't taste tart and its pH is on par with wheat beer.  If you are tasting something tart its an organic acid or its salt.

Tom,

I don't think wheat beer tastes tart.

Pepsi has a pH of 2.5, if I remember correctly, and that is 1.5 pH units below a normal wheat beer.

Good point about the organic acid and the tart taste. It must be something else than the low pH that causes this.

Kai
Title: Re: Shift in thought regarding optimal mash pH
Post by: tomsawyer on August 14, 2012, 12:19:17 PM
I know there are commercial weizens htat are not tart, but a lot of people report a certain citric tartness in their wheat beers.  Some like it, some don't.  I've tried to minimize this with mixed results, which is why I'm interested to know the underlying causes.
Title: Re: Shift in thought regarding optimal mash pH
Post by: mabrungard on August 14, 2012, 12:28:56 PM
Don't forget that the anion associated with the acid can have a profound effect on the perception of tartness.  Malic acid is the stuff used in those sour candies.  Phosphoric acid is one of the more neutral tasting acids.  Lactic acid is somewhere between.
Title: Re: Shift in thought regarding optimal mash pH
Post by: brewmichigan on August 14, 2012, 02:36:52 PM
Cool photo.  Does that say 52.5 C?

52.5 degree Celsius = 126.5 degree Fahrenheit

So maybe they aren't waiting to cool it completely...

So remind me again why we measure at room temp and then do a conversion? Are pH meters significantly off at any higher or lower than room temp?

It sat there for quite a while and I'm pretty sure that it ended up at room temp.  Mike K., you out there?  Do you recall?

A little late to the party but they started with it at mash temps and put the probe directly in. It then sat for a long time and eventually cooled to almost room temp. I remember it being spot on, 5.2 ph, when it finished.
Title: Re: Shift in thought regarding optimal mash pH
Post by: denny on August 14, 2012, 04:12:34 PM
A little late to the party but they started with it at mash temps and put the probe directly in. It then sat for a long time and eventually cooled to almost room temp. I remember it being spot on, 5.2 ph, when it finished.

Thanks, man.  That's how I recalled it, too.
Title: Re: Shift in thought regarding optimal mash pH
Post by: jmcamerlengo on August 17, 2012, 06:59:35 PM
This has always been a very confusing topic to me. I've tried to standardize my practice with things Ive read from Kai, Martin and Gordon among others(thanks guys!). What Ive come  up with as my standard is this.
Assuming the bulk of my mash time is spent in the 148-158F range.
I will measure pH at room temperature and adjust about .2 for the pH of the mash.
I typically try to achieve a ph of 5.2 - 5.5 at mash temps. So 5.4-5.7 at room temps.
I do 5.2 for beers that I want to have a bit of twang(heffs, wits)
I do 5.5 for beers that I want malty(stouts, scot beers etc)
5.3-5.4 for everything else.

Not sure if my logic is flawed but at least its something that is consistent from batch to batch and I can adjust from there with acid/pickling lime.
Title: Re: Shift in thought regarding optimal mash pH
Post by: positiverpr on August 18, 2012, 11:32:11 PM
i'm doing about the same as you except that i like a little more sharpness so i shoot for 5.2 - 5.4(room temp). i always assumed that i was helping to preserve my beer a little better by keeping a slightly lower ph. interestingly, i was re-listening to an interview with dr bamforth last week and he commented that although beer
"cleanliness" was enhanced with acidity its "freshness" was shorthened. i'm paraphrasing on the terminology. no reference for the data but it was his visit on the brewing network session last year. anyone have input on this subject? does the source of the acidity make a difference(phos or lactic acid versus dark malt with their included anti-oxidants?) so much research to be done!
Title: Re: Shift in thought regarding optimal mash pH
Post by: Kaiser on August 18, 2012, 11:43:20 PM
There is actually data that shows that the beer pH will be higher when the mash pH was lower.

the reason for this is that the low mash pH favors enzymes that increase the wort's buffer capacity. The yeast has a harder time lowering pH in this environment.

As a result many German breweries do some acidification in the mash and then more in the kettle.

Kai
Title: Re: Shift in thought regarding optimal mash pH
Post by: dbarber on August 25, 2012, 01:47:08 AM
I realize that ideal mash conditions are in the 5.2-5.7 range, but what is the real difference of a mash conducted at 5.2 vs. 5.6 in terms of beer flavor.  This would be a great experiment.  How does this effect mash efficiency or beer flavor.  I think Kai has conducted some experiments in this regard.  I've made excellent beers at both ends of the pH spectrum. Tannin extraction increases with increasing pH, but what can be said for a mash conducted on he higher side of the range?

This is an interesting mechanism that isn't clearly understood in terms of it's effect on the end product. I would like to see some further experimentation on the effects of mash pH on beer flavor.

Ron, sounds like a great talk for the NHC next year.
Title: Re: Shift in thought regarding optimal mash pH
Post by: zorch on September 04, 2012, 10:48:25 PM
As a result many German breweries do some acidification in the mash and then more in the kettle.

I'm curious - How would a German brewer acidify a wort that's already in the kettle?   I was under the impression that spiking it directly with an acid would not be allowed according to the Reinheitsgebot.
Title: Re: Shift in thought regarding optimal mash pH
Post by: Kaiser on September 04, 2012, 11:28:44 PM
With wort soured throug lactic bacteria from malt.

Kai
Title: Re: Shift in thought regarding optimal mash pH
Post by: denny on September 05, 2012, 03:58:13 PM
As a result many German breweries do some acidification in the mash and then more in the kettle.

I'm curious - How would a German brewer acidify a wort that's already in the kettle?   I was under the impression that spiking it directly with an acid would not be allowed according to the Reinheitsgebot.

Kai can likely speak to this more authoritatively, but I'm under the impression that most German breweries don't worry about the R'gebot.
Title: Re: Shift in thought regarding optimal mash pH
Post by: Kaiser on September 05, 2012, 04:18:49 PM
Kai can likely speak to this more authoritatively, but I'm under the impression that most German breweries don't worry about the R'gebot.

No, they still do. I'm not exactly sure what the legal situation is, but beer brewed in Germany has to comply with the RHG to be called beer. Imported beer may not. However, the most value that brewers see in following the RHG is its marketing value. You don't want to be the first brewery who does not follow it. There was some severe backlash last when in 2006 Bitburger mentioned that they would consider rice and corn if the barley harvest doesn't supply enough malt. They had to release a statement saying "the purity law is untouchable".

Germans are very inventive when it comes to complying with the purity law yet being able to advance brewing technology. Just look at CO2 hop extract it complied with the purity law b/c fermentation CO2 is used for extracting the resin.

Kai
Title: Re: Shift in thought regarding optimal mash pH
Post by: denny on September 05, 2012, 04:44:59 PM
Thanks, Kai!