Author Topic: Mash PH  (Read 1876 times)

Offline Semper Sitientem

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Mash PH
« on: April 29, 2020, 08:47:55 AM »
If 5.2 is the ideal PH and 5.2 - 5.6 is the “good range”, is there any benefit of lowering my mash PH from say a 5.6 to a 5.5 or lower?
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Offline Silver_Is_Money

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Re: Mash PH
« Reply #1 on: April 29, 2020, 09:57:47 AM »
This entire subject opens a major can of worms and leads you to rabbit holes you might fall into.  And stepping outside of the modern line of reasoning here is not a great way to win friends (ask me how I know).  Despite taking much flak from moderns who follow myriads of modern era magazines and books (typically not peer reviewed) of pablum/mantra published with an opinion to the contrary, I've come to the opinion that much of the older peer reviewed literature indicates upon a careful analysis that mash pH's were (back then) measured at mash temperature.  Sometimes this is even made explicit and comparisons to room temperature are made (almost universally by adding 0.3).

This implies that mash pH back then was something accomplished at a range somewhat higher than is considered normal today, wherein we tend to look at all pH related things in terms of their room temperature pH measure, and we also somehow collectively contort the masters words of yore to conform to our modern worldview that pH is always to be taken at room temperature, thus seeing their 5.4 ideal as being at room temperature (albeit that it was not).

Off the top of my head it was Briggs who most explicitly expressed this, when he openly stated in writing that his ideal mash pH range when converted to room temperature (wherein he specifies an added 0.3 pH points to facilitate the conversion) becomes 5.5 to 5.8 pH.  Similar data can be teased from others such as Narziss and the rest if one desires to take the effort to do so.  Modern pH instrumentation seems to more closely adhere to a difference of 0.2 points when converting from mash temperature to room temperature pH readings, so for today's pH meters Briggs room temperature ideal mash pH range becomes 5.4 to 5.7 (with a mid-range ideal of 5.55).

But there is a catch.  Today we tend to conflate what was once two separate pH adjustments that were commonly made in yore into only one.  And we generally presume that if we mash at ~5.4 as measured at room temperature we will exit the boil at a cooled to room temperature Wort pH of ~5.1-5.2.  The masters of yore acid adjusted the boil to 5.2 as measured at room temperature (after earlier having adjusted the (room temperature) "Mash" to 5.5 - 5.8 pH (5.4 to 5.7 for a modern meter), thus making two adjustments.

All literature mentions a drop in pH across the boil, but some of the peer reviewed literature which actually took the time to measure this (as opposed to regurgitating the presumptions of others) speaks of a drop in pH across the boil that is greater in magnitude when entering the boil with Wort at room temperature pH's of 5.4 and above, and with the observation that once Wort is at ~5.2 pH (room temperature) or below this pH drop witnessed across the boil ceases. So the magnitude of the pH drop across the boil is greater the higher ones pH is going into the boil, but somewhere around pH 5.1-5.2 any further drop across the boil ceases.  The boil drop is therefore not fixed in magnitude (typically with a presumed 0.3 point drop), as is commonly believed today, and was presumed incorrectly even as such within much peer reviewed literature of yore.

I believe it was Bamforth who made it clear that this pH drop across the boil can not be relied upon to occur at any predictable degree of reliable measure (or magnitude), so the presumption that we make today of hitting 5.2 post boil and cooling when starting at around 5.4 at room temperature in the mash is not something we should "take to the bank" (such as we do).

But since once a room temperature measured ~5.2 pH is achieved there is little to no further drop in pH anticipated to be observed across the boil, your choice of mashing at room temperature 5.2 and then lautering, sparging, and boiling should easily accomplish the task of exiting the boil at 5.2 pH or right close (perhaps as low as 5.1).  5.2 mash pH may however be below the ideals seen for enzymes and saccharification yield and the like, as 5.55 room temperature pH for the mash seems to best tickle all of these buttons (as attested by the masters of yore).  By considering mashing at room temperature 5.2 pH you are among those (nearly all of us) today who have conflated two acidification steps into one.  But a growing trend is emerging to once again revert to two pH adjustments.
« Last Edit: April 29, 2020, 10:40:40 AM by Silver_Is_Money »

Offline ynotbrusum

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Re: Mash PH
« Reply #2 on: April 29, 2020, 11:02:00 AM »
That is a lot to absorb from Silver_Is_Money, but for simplicity, I would answer it this way:
If your mash pH is in the range you want for the style you want, there is no need to further adjust it.  Further, adding salts that put your beer out of the right flavor profile is not worth doing, obviously.  Adjusting with phosphoric or lactic acid should not be terribly noticeable from a flavor profile, so if you want to push it lower yet within range, consider the liquid acid additions or acidulated base grain.

I am not taking issue with the prior poster, because I tend to rely on the calculators, rather than actual measurement, so I don’t have verification of mash or boil pH predictions each time, rather when I have measured pH in the past it was at room temperature and it was only of the mash - which hit the predicted marks so closely and consistently that I found it unnecessary to continue with that practice.  Others may want assurance each time and that is cool with me!
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Offline Silver_Is_Money

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Re: Mash PH
« Reply #3 on: April 29, 2020, 11:46:40 AM »
Here is the Cliff's Notes (like) version of my above lengthy dissertation.

1) Mash while targeting a room temperature measured 5.55 pH.
2) Adjust pH to 5.1-5.2 (as measured at room temperature), either just before, or sometime during the boil.  Some even choose to do this post boil.

Since pH fluctuates across the mash, I should also mention that you are deluding yourself if you are taking mash pH readings at less than 30 minutes into the mash.  For a 60 minute mash, a sample taken at the 60 minute mark will give you the most reliable "Mash pH".  But you shouldn't typically see much change after 30 minutes.

Offline BrewBama

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Mash PH
« Reply #4 on: April 29, 2020, 12:23:53 PM »
I brewed a series of the same APA recipe last summer only changing the hops.  For each I took readings every 20 min. My mash pH did not fluctuate appreciably over the mash (+/- .03). Below is an example but every batch looked nearly identical. I could overlay them on a graph and it would be very difficult to distinguish one from the other.

20 min 1.045, 5.47 pH,
40 min 1.056, 5.47 pH,
60 min 1.060, 5.50 pH,
80 min 1.065, 5.44 pH,
90 min 1.069, 5.46 pH,

Therefore, I now take a reading at 20 min just to see if my prediction and addition to my brewing liquor prior to mash in is correct. My target is 5.4 at room temp. I make no further adjustments.

If 5.2 is the ideal PH and 5.2 - 5.6 is the “good range”, is there any benefit of lowering my mash PH from say a 5.6 to a 5.5 or lower?

I refer you to this table from the Water Knowledge page of Bru’n Water:




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« Last Edit: April 29, 2020, 12:38:46 PM by BrewBama »
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Re: Mash PH
« Reply #5 on: April 29, 2020, 12:35:49 PM »
I've come to the opinion that much of the older peer reviewed literature indicates upon a careful analysis that mash pH's were (back then) measured at mash temperature. 

I always go back to DeClerck, who in his 1947 book, "Cours de Brasserie", later translated as "A Textbook of Brewing" in 1957 (emphasis added for dates), cites "cooled wort" exclusively, throughout the 2 volumes, when referring to mash pH.

Frankly I don't even think metering capable of accurate measurement at mash temps was available until well into the 1960s, but I have been wrong before. YMMV.

If 5.2 is the ideal PH and 5.2 - 5.6 is the “good range”, is there any benefit of lowering my mash PH from say a 5.6 to a 5.5 or lower?

We've had good luck with a universal target of 5.4 (room temp) in the mash and acidifying to 5.1-5.2 near knockout. There are benefits with respect to wort quality, DMS formation and removal properties, etc. but for the time being that may be outside the scope of your post.

Good luck!

Offline Silver_Is_Money

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Re: Mash PH
« Reply #6 on: April 29, 2020, 12:41:56 PM »
Not all pH meters use glass electrodes.  I was using analog pH meters with antimony electrodes in the early 1970's in a professional setting.  And these instruments looked primitively ancient and well past their prime to me back then.

Offline BrewBama

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Re: Mash PH
« Reply #7 on: April 29, 2020, 01:00:17 PM »
Not all pH meters use glass electrodes.  I was using analog pH meters with antimony electrodes in the early 1970's in a professional setting.  And these instruments looked primitively ancient and well past their prime to me back then.
  I use a MW101 pH meter operated by a hack home brewer in a definitely unprofessional setting.


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Offline Silver_Is_Money

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Re: Mash PH
« Reply #8 on: April 29, 2020, 01:26:24 PM »
I should add that I'm not at all advising or recommending in any of this that anyone at the homebrewer level actually measure their mash pH at mash temperatures.  I will however state that in an industrial setting it is quite possible to continuously monitor pH at such high temperatures as for mash.

Offline HopDen

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Re: Mash PH
« Reply #9 on: April 29, 2020, 01:38:21 PM »
All literature mentions a drop in pH across the boil, but some of the peer reviewed literature which actually took the time to measure this (as opposed to regurgitating the presumptions of others) speaks of a drop in pH across the boil that is greater in magnitude when entering the boil with Wort at room temperature pH's of 5.4 and above, and with the observation that once Wort is at ~5.2 pH (room temperature) or below this pH drop witnessed across the boil ceases. So the magnitude of the pH drop across the boil is greater the higher ones pH is going into the boil, but somewhere around pH 5.1-5.2 any further drop across the boil ceases.  The boil drop is therefore not fixed in magnitude (typically with a presumed 0.3 point drop), as is commonly believed today, and was presumed incorrectly even as such within much peer reviewed literature of yore.

My observations are the opposite, I always check the boil pH at the end and at room temperature (60*)and my pH is always higher. It is only after fermentation that I see a drop in pH, again at 60*

Offline Die Beerery

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Re: Mash PH
« Reply #10 on: April 29, 2020, 01:59:17 PM »
Coming from a guy who measures mash, and room, every brew session, and chases perfection and is also has some professional schooling. I target 5.4 mash, then 5.1 knockout.
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Offline PORTERHAUS

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Re: Mash PH
« Reply #11 on: April 29, 2020, 02:07:52 PM »
If 5.2 is the ideal PH and 5.2 - 5.6 is the “good range”, is there any benefit of lowering my mash PH from say a 5.6 to a 5.5 or lower?

Like many things in life and brewing, certainly there is benefit to be within the ideal range of 5.2-5.6...5.6 being the very limit. I have listened to several podcasts with commercial breweries indicating a target mash temp...Sierra Nevada indicated they target 5.3 for their Pale Ale, Lagunitas indicated 5.3-5.4, and said they don't worry if it's as high as 5.5. I target ~5.35 so that I have some cushion either way and be fine. There are reasons for the ideal range, maximum efficiency, enzyme activity, color development...etc. Mash ph will have an impact on everything else downstream from it.

One thing I want to note is I had confusion on this early on between the ph at mash temp/vs room temp thing. I do not know where it started for me or where I went wrong but it's important to realize that when mash ph is referenced it is at room temp...that is the standard. There are some out there that adjust for the difference or literature that speaks of doing so...forget all all and just remember mash ph is referenced with a room temp sample.

Offline HopDen

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Re: Mash PH
« Reply #12 on: April 29, 2020, 02:22:03 PM »
https://www.homebrewersassociation.org/seminar/czech-plz-what-i-learned-brewing-with-the-czech-masters/

If interested, this seminar given by Annie Johnson, speaks about Czech Pilners and her visits to Pilsner Urquell. In it, she claims their "mash' pH is 4.7-4.9 She also claims this was stated to her by Head Brewmaster Vaclav Berka. She states that that is the pH she targets for her Czech Pilz and claims it is that low pH that drives the familiar flavor of Pilsner Urquell specifically and Czech beers in general.

If anything, it is a good seminar to watch.

Offline goose

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Re: Mash PH
« Reply #13 on: April 29, 2020, 02:47:50 PM »
I brewed a series of the same APA recipe last summer only changing the hops.  For each I took readings every 20 min. My mash pH did not fluctuate appreciably over the mash (+/- .03). Below is an example but every batch looked nearly identical. I could overlay them on a graph and it would be very difficult to distinguish one from the other.

20 min 1.045, 5.47 pH,
40 min 1.056, 5.47 pH,
60 min 1.060, 5.50 pH,
80 min 1.065, 5.44 pH,
90 min 1.069, 5.46 pH,

Therefore, I now take a reading at 20 min just to see if my prediction and addition to my brewing liquor prior to mash in is correct. My target is 5.4 at room temp. I make no further adjustments.


I too have noticed this when I took readings across a set of intervals through the mash.  It doesn't change that much and I normally measure about 10-15 minutes into the mash on a brew day (draw a sample, cool to room temp, measure) and either leave it alone or adjust to bring it into range.  I know that others say this is too soon, but it seems to work for me and reflects Brewbama's data and the data I have collected.

I don't dispute any of the comments made by Silver_Is_Money or others.  However for the sake of information purposes, I have been taking both mash and post boil gravity measurements, based on an older thread on this forum, for quite a while now so that I could gather some data points.  Here is data from my last 6 brews all taken at room temperature with a Milwaukee SM-102 pH meter calibrated every 30 days.  Obviously, this is not in a lab environment.


Beer          Mash pH          Post Boil pH
Saison          5.18(5.37)         5.20                     Mash pH was adjusted to 5.37 with baking soda to bring it into range
Irish Red       5.46                  4.93
Amarillo IPA   5.46                  5.32
Black IPA       5.47                  5.18
Tripel            5.47                  5.40
Wee Heavy    5.30                  4.93

Is this conclusive, probably not.  I suspect the lower post boil readings for the Irish Red and the Wee Heavy might come from the dark grains, but who can be sure.  I am just sharing what I have observed.  I will continue to do this to gain more data
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Re: Mash PH
« Reply #14 on: April 29, 2020, 03:15:10 PM »
https://www.homebrewersassociation.org/seminar/czech-plz-what-i-learned-brewing-with-the-czech-masters/

If interested, this seminar given by Annie Johnson, speaks about Czech Pilners and her visits to Pilsner Urquell. In it, she claims their "mash' pH is 4.7-4.9 She also claims this was stated to her by Head Brewmaster Vaclav Berka. She states that that is the pH she targets for her Czech Pilz and claims it is that low pH that drives the familiar flavor of Pilsner Urquell specifically and Czech beers in general.

If anything, it is a good seminar to watch.

Anyone who has tried Annie's pils knows of what she speaks.
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