Dec 17 BYO response to Mash pH questions

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jwalkermed

jwalkermed

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There was quite a storm in the new BYO that just dropped regarding mash pH measurements. Specifically weather the ideal mash pH is 5.2 - 5.6 @ mash temp or room temp. Starting on pg 21.

It seems Ashton Lewis (Mr. Wizard) feels this ideal pH range refers to measurements taken mash temp and quoted some references. This contradicts what others have claimed ( that the pH refers to room temp measurements).

I'm interested in what AJ Delange or Martin Brungard's thoughts are on this response.

EDIT: Name typo
 
reason #2 why i decided not to renew BYO this year after having it for 7 years. this article, along with a few others, seriously questions the validity of everything they publish.
 
schematix said:
reason #2 why i decided not to renew BYO this year after having it for 7 years. this article, along with a few others, seriously questions the validity of everything they publish.
Click to expand...

Ya know its like everything in life. Sometimes you have to wade through the garbage to find the gems. I still like BYO. I'd just encourage everyone to seek out the truth and not believe everything you hear or read. Just good advice for life in general.

I won't really change my process regardless. I use brew n water and target the appropriate range in that spreadsheet. I don't even take measurements anymore because I found the spreadsheet was close enough and the resulting beer is good.
 
Hmm...... Kai Troester and Gordon Strong have weighed in on this previously..... Kai seems to think (or at least did in 2011) that the oft-quoted range of 5.1-5.5 is for mash temperatures, and that at room temperature this range should be closer to 5.4-5.8.

I know, I know -- I had to do a double-take, too. See here:

https://www.homebrewersassociation.org/forum/index.php?topic=6168.0
 
I think the active range of amylases is the usual explanation for the pH range between 5.2 and something. For that reason one should check the original papers that describe this range to see how they measured the pH, did they cool down the mash or calibrate some other way?

In practice it is more complicated. pH will have an effect on yeast, proteins and hops (and many more things) as well and I don't think we can say that there is one specific pH or a narrow range that would be ideal. At the end, it all comes to taste and the recipe.

I recently found this. As I understand, it suggests some very low mash pH ranges for some beer styles in slide nr 14 or 15. In fact, much lower than pH5.2 (or is there some mistake in that slide, maybe final pH of the beer?). Probably mashing that low would take extra time. Would be interesting to see some practical experiments on this.
 
I finally found it! Difference between pH at mash temperature vs. room temperature is approximately 0.2 (0.18-0.22 or something like that). So the goal then really, from what I can tell, is to aim for 5.2-5.3 at mash temperature OR 5.4-5.5 at room temperature. Take your pick. Measurement at mash temperature is easier but hurts your gauge. And whenever documenting a pH, the convention is that you MUST report it at room temperature. So if measuring at mash temperature, you need to add 0.2 and report THAT number, NOT the room temperature number.

Make sense to anybody out there!? Here is the key to the universe:

https://www.homebrewersassociation.org/forum/index.php?topic=4739.msg55106
 
I finally had a chance to read Ashton Lewis's response in Dec 2017 BYO, and have to say that he and I are on the same page. For measuring pH at room temperature vs. mash temperature, Lewis reports a pH swing of 0.25, which is consistent with Kai Troester's 0.22 and Gordon Strong's 0.2-0.3. Lewis says the 0.25 is second-hand sourced from John Palmer and that it was "empirically determined", i.e., by hard science. If all these sources, plus others that Lewis provides, are all finding pretty much the same thing, heck, that's confirmation enough for me.

Bottom line is like I said above -- we need to be shooting for 5.4-5.5 at room temp. Lewis says this is more like 5.45-5.75. Whatever. It's right around there. My 5.4-5.5 is based on my own experience for the batches that turned out the best in my own homebrewery -- looks like I prefer to aim for the lower end. And, when measuring directly in my mash which yes I do, I'm actually shooting for 5.2-5.3 now at mash temps around 150 F or so.

Clear as mud, right!? I think Lewis did a pretty O.K. job pulling together multiple sources to try to provide a more definitive answer. And I think the links I've provided above can be added to the mix as well.

IF anyone gives a crap, read ALL of this material, then make up your own mind. I wouldn't take any one person's word for it either. Review all inputs and make informed decisions.

Cheers.
 
Ok, so its ~5.2 pH ideal if measured at mash temperature or 5.45 pH ideal if measured at room temperature. All that one needs to remember is that most if not all mash pH assistant software expects room temperature measurement, and compensate for it if taking the reading at mash temperature. Therefore nothing has changed due to the publication of this article in BYO.
 
Disagree. I learned long ago that the optimal mash pH is 5.3. What I did not know until now is that this is at mash temp, not room temp. True, if you shoot for like 5.3 or 5.4 without caring at all about temperature, you'll probably be okay! But on the other hand, if you're "just a little off" and measure 5.5 at mash temp, or 5.2 at room temp, you might not get as great efficiency or flavor as if you'd adjusted.

Knowledge is power. Soak it up.
 
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My own experience has been that lagers are best with a room temp mash pH of 5.45 - 5.55. Depending on what you consider to be mash temp (beta glucan rest, protein rest, saccharification rest) and the glides (shift in DI mash pH with temp.) that could correspond to 5.3 at mash temp.
 
Absolutely and only...ROOM-TEMPERATURE MEASUREMENT!!!!

As already pointed out, inserting a pH probe in and out of hot wort WILL shorten its life. In addition, the pH offset due to temperature difference is well-known. So there is little problem in extrapolating what a mash's pH is at it's mashing temperature.

While crappy pH meters that few would place much confidence in, are cheap, a reliable and trustworthy meter is going to be more expensive. Protecting that investment is worthwhile to me. I've got plenty going on during mashing and my experience is that collecting a sample and placing it in a glass to cool, is no big deal for me.

To say that there is an "optimum" pH that we should mash at, is a fool's errand. There are a lot of "optimums" at work in the mash and its the brewer's prerogative to decide what that value should be for the brew at hand. Keying that optimum to mashing temperature is just chasing your tail.

The bottom line is that brewers should measure mashing pH with a room-temperature measurement and key that information to how the beer turns out. Successive brews at slightly differing pH will define what the brewer really wants to target.

Who cares what pH is at mashing temperature?
 
mabrungard said:
Who cares what pH is at mashing temperature?
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With all due respect, sir... see link at #12 above. Even you were interested in this topic at one point in time, perhaps at a time when there were a lot more people a lot more intelligent than I to argue with online. The questions of "which temperature" or "why care" are questions that probably thousands of brewers have had in the past, and will continue to have in the future.
 
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You're right Dave, but the knowledge and understanding has advanced in the 7+ years since that conversation. I still feel that brewers are better off 'calibrating' their brewing results to the more stable and repeatable room-temperature pH measurement.
 
I always point out that when one says "mash temperature" we need to ask what mash temperature he is referring to. Cold dough in (as in some lager brewing)? Beta glucan rest? Protein rest? Low saccharification rest? High saccharification rest? Leaving out cold dough in we have a range of from 110 to 150 °F. The drop depends on temperature. There is a slope which, in my experience, is somewhere around 0.0055 pH/°C but different malts have different values.

This to me is a strong argument fort specifying at room temperature. It's always room temperature. The reason we don't care about the actual mash pH is because we know that if we get it correct at the standard temperature things will turn out well for us. It's sort of like pilots setting their altimeters to 29.92 above 18,000 ft irrespective of the local barometer. They don't care what altitude they are actually at being confident that if their altimeters read FL 200 they won't run into traffic at FL 201.
 
Just read the December BYO article and it caught me a little off guard to be honest. I have usually targeted 5.2 - 5.4 at room temp (typically 5.3 nowadays). At the lower end that seems to be out of the accepted range. A lot of contradictory (or unspecific) information out there.

If I were a new AG brewer it seems 5.5 - 5.6 at room temp would be a better "starting" spot and adjust from there based on results - which is NOT what is commonly disseminated on home brew forums.
 
mabrungard said:
You're right Dave, but the knowledge and understanding has advanced in the 7+ years since that conversation. I still feel that brewers are better off 'calibrating' their brewing results to the more stable and repeatable room-temperature pH measurement.
Click to expand...

I agree with you here. Room temperature reporting (STP, i.e., standard temperature & pressure) is the standard in most science, and always should be. That is why I record everything as room temperature measurements even when I might choose to measure at mash temp. Am I naughty? Sure, probably. But I also try to be as accurate and honest and forthright as possible, and I really won't try to talk anyone out of doing the right stuff even if I myself am crazy enough to do the wrong stuff.
 
popquizkid said:
Just read the December BYO article and it caught me a little off guard to be honest. I have usually targeted 5.2 - 5.4 at room temp (typically 5.3 nowadays). At the lower end that seems to be out of the accepted range. A lot of contradictory (or unspecific) information out there.

If I were a new AG brewer it seems 5.5 - 5.6 at room temp would be a better "starting" spot and adjust from there based on results - which is NOT what is commonly disseminated on home brew forums.
Click to expand...

Exactly. You get it. This is why I'm being so vocal about all this (on this thread anyway), because I believe the vast majority of brewers blindly accept the misinformation that's being fed to us.
 
dmtaylor said:
Room temperature reporting (STP, i.e., standard temperature & pressure) is the standard in most science, and always should be. That is why I record everything as room temperature measurements even when I might choose to measure at mash temp. Am I naughty?
Click to expand...

Naughty? No. In fact taking measurements at mash and room temperature is really the way to go. To eliminate stress on the probe gently warm some DI water to mash temperature with the probe in it i.e. bring the probe up to mash temperature slowly. Now take your mash temperature sample and move the probe to it quickly. 'Stir' the sample well to be sure to rinse the DI water off and record pH. Do this at several temperatures as the sample cools and record. You will get a curve which is pretty nearly linear which you can fit and from which you can deduce the 'glide' for this particular grist. Let is know what you get.
 
ajdelange said:
Naughty? No. In fact taking measurements at mash and room temperature is really the way to go. To eliminate stress on the probe gently warm some DI water to mash temperature with the probe in it i.e. bring the probe up to mash temperature slowly. Now take your mash temperature sample and move the probe to it quickly. 'Stir' the sample well to be sure to rinse the DI water off and record pH. Do this at several temperatures as the sample cools and record. You will get a curve which is pretty nearly linear which you can fit and from which you can deduce the 'glide' for this particular grist. Let is know what you get.
Click to expand...

I like the way you think. I will do this and report back. My next batch will probably happen sometime the first week of December, plus or minus the whenever-I-get-around-to-it factor.
 
so here's a question --

brunwater shows "mash pH" in your minerals and summary pages. dont see anything in comments or instructions stating what temp that's at.

but without a mash temp to calculate for pH drop due to heat, i'd assume this figure could only be accurate for pH measured at room temp. so is it actually pH at room temp?

because at first glance, i'd think most folks would assume its at mash temp.

What say you MATT Brungard?
 
My experience is the pH calculations in the water calculators is that they line up(pretty accurately for me) to room temperature mash readings that I have taken.

At this point maybe I am mistaken on that as well. The fact that I was unintentionally undershooting my mash pH (5.2 - 5.4 at room temp) for the past three years still has me scratching my head a bit.
 
SanPancho said:
so here's a question --

brunwater shows "mash pH" in your minerals and summary pages. dont see anything in comments or instructions stating what temp that's at.

but without a mash temp to calculate for pH drop due to heat, i'd assume this figure could only be accurate for pH measured at room temp. so is it actually pH at room temp?

because at first glance, i'd think most folks would assume its at mash temp.

What say you MATT Brungard?
Click to expand...

Bru'n Water, on the instructions page (Tab 0), says pH should be at room temp (at least in the supported version).

This is off the Bru'n Water website on the "Water Knowledge" page: "Brewers should note that Automatic Temperature Compensating (ATC) pH meters only compensate for the response of the pH meter's electrode at varying temperature. That feature does not compensate for the actual pH shift produced chemically in the mash as mentioned above. All mash pH measurement should be performed at room-temperature. Another consideration is that most pH probes use a thin glass bulb that will be subjected to more thermal stress when inserted into a hot mash and the probe is more likely to fail prematurely. Therefore, ATC-equipped pH meters are not necessary for brewing use since it is important to cool the sample to room temperature to avoid the chemical mash pH variation and damage to the pH probe.
 
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Probably time to update that. I think you would be hard pressed to find a modern pH meter without ATC though if you look hard enough you will probably find a couple. Not too far back I did stumble across one such with a mirrored D'Arsonval meter and knobs and thought that would be pretty cool to play around with but they wanted several hundred dollars for the thing. It's still there! https://www.coleparmer.com/i/cole-parmer-laboratory-ph-mv-meter-analog/0599650. This is one of their 'economy' ($350 is economy at Cole Parmer) meters.
 
shetc said:
Does this mean it is okay to use my Milwaukee pH Meter With ATC at mash temps?
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Not necessarily. It means that all modern meters contain the ATC function. It would be rather pointless to build a digital meter without ATC. Your Milwaukee meter, if recent, has it.

The question is as to whether it is prudent to measure at mash temperature. As indicated here whenever people are talking mash pH they are talking room temperature. I guess there are still a couple of people out there who are unaware of this but most are. Also, rapid temperature changes impose stresses on pH sense bulbs and thus shorten their lives. Most people use their meters at room temperature for these reasons. But if you choose to use your meter at mash temperature it will report actual pH at mash temperature with the inclusion of a small error if your meter's isoelectric pH isn't exactly 7.0. This can usually be ignored.
 
So, if I use a pH meter with ATC in, say, the 70-90°F range, I'll be ok? The last pH meter I used weighed 80lbs, used vacuum tubes, and looked like a Frankenstein movie prop, so I've got some catching up to do.
 
The old classic doubtless had knobs for slope (gain) and offset and probably a third knob for temperature. The offset knob adds a small voltage (equal in magnitude and opposite it sign) to the probe's voltage at pH 7. The gain knob adjusts the gain of the op amp such that the meter reads 4 in pH 4 buffer. The temperature knob dials in extra gain in proportion to the temperature relative to a reference temperature. You have to measure the temperature of the sample and set the dial to the measured temperature. In ATC the same things are done except the gains and offsets are simply scale factors determined from measurements of voltage when the probe is in solutions (buffers of know pH) and temperature. And its all automatic.

Between 70 and 90 you aren't going to stress the probe too much but if you arrange to have the temperature change slowly from room to 90 and then slowly back t0 70 you will stress it even less.
 
Thank you, that's just what I hoped to hear. I've bought a truly horrible 'disposable' import meter, just to get over the steep part of the learning curve. No expectation of long life.

I thought, take a sample in a small (1 cup?) ss mixing bowl.

It will cool quickly, and with ATC I won't need to sweat 5-10°F variations.
 

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