Brew Day pH results

[North_of_60]

I brewed a Wit beer today based of Brad Smith’s recipe. Brad’s is a 10 gallon, I reduced it to 5 gallons, reduced the IBUs and used WY 3068. Other than that, I followed his recipe pretty close.

Below is the data. I don’t know if there is anything useful in it, but never-the-less here it is:

8.5 gallons Ft Worth Water adjusted to Yellow Balanced profile using BS3.
(Ft Worth Water: 44 ppm Ca, 5.3 ppm Mg, 17.8 ppm Na, 29.6 ppm SO4, 23.9 ppm Cl, 126 ppm HCO3)
5 ml Lactic Acid 88% (Per Bru’n Water)
3 g Epsom Salts (Per BS3)
2 g Calcium Chloride (Per BS3)
4.5 lbs. Pale 2 Row Belgium 3.0 SRM
4.5 lbs. Flaked Wheat 1.6 SR
.6 oz East Kent Goldings (60 minutes boil)
.75 oz Coriander Seeds crushed (5 minutes boil)
.75 oz Bitter Orange Peal (5 minutes boil)
WY 3068

I did a full volume BIAB Mash for 90 minutes and added the salts (as recommended in BS3) and 5 ml of Lactic Acid (as calculated in Bru’n Water) before I started to heat the mash water. I added the mash at 154 F and after a thorough stirring the mash temp was 150 F. I checked the pH at the following intervals:

23 Min pH 5.57 cooled to 80 F
55 Min pH 5.66 cooled to 80 F
90 Min pH 5.71 cooled to 80 F
(Room temperature at my house is 72 F)

My pH meter was calibrated just prior to taking the first reading. When it came out higher than expected I cleaned, dried and tested it in the 6.86 solution and it read 6.86. This was repeated in the 4.01 solution and it read 4.01. The wort then retested and again read 5.57.

Bru’n Water recommended 5 ml of lactic acid for a pH of 5.30 (below 23 Min by .27)
Mash Made Easy predicted that 5 ml would yield a pH of 5.64 (over 23 Min by .07)
BeerSmith 3 predicted that 5 ml would produce a pH of 5.59 (over 23 Min by .02)

To achieve a pH of 5.30:
Bru’n Water recommended 5.0 ml
Mash Made Easy recommended 8.78 ml
BeerSmith 3 recommended 10.3 ml

I may have made some errors inputting numbers into the various calculators, but I don’t see them. Next brew day I’ll use MME for lactic acid and report the results.

 

[Silver_Is_Money]

Nice report!

PS: As I see this (I.E., in my opinion) I would suggest that if your mash pH was 5.71 at the very end of the mash, that is your actual mash pH, as that is when the very last traces of starches were being converted into sugars.

Which versions were used for MME and BW please?

 

[North_of_60]

Nice report!

Which versions were used for MME and BW please?

BW 1.23
MME 3.10

EDIT: My OG was 1.50 estimated 1.49

 

[ScrewyBrewer]

Just an observation. @Silver_Is_Money yesterday I thought you said 30 minutes into the mash was 'the standard' for taking mash pH measurements?

@North_of_60's recipe as posted is using a 3.78 qt/lb mash thickness. I point that out because I brew my Witbier recipe using BIAB and a 2.0 qt/lb mash thickness and I though that was high.

Starting out with 8.5 gallons of RO water I wasn't able to exactly replicate @North_of_60's source water....
44 ppm Ca, 5.3 ppm Mg, 17.8 ppm Na, 29.6 ppm SO4, 23.9 ppm Cl, 126 ppm HCO3. [Fort Worth water]
44 ppm Ca, 5.0 ppm Mg, 47.0 ppm Na, 91.0 ppm SO4, 24.0 ppm Cl, 126 ppm HCO3. [RO water with additions]

Adding 4.5 lbs of Belgium Pale 2-Row and 4.5 lbs Flaked Wheat this is what I get...

Then I add in @North_of_60's additions of 5 ml Lactic Acid 88%, 3 g Epsom Salts, 2 g Calcium Chloride and get.

Please let me know if I have gone about this in the same way you have.

 

[Silver_Is_Money]

Just an observation. @Silver_Is_Money yesterday I thought you said 30 minutes into the mash was 'the standard' for taking mash pH measurements?

As of only this morning I have abandoned any attempt to standardize upon mash pH timing as frivolous. I'm moving to "wort pH" as the standard, since standards require reaction end point level stability, and the only time such a static condition is to be seen within the mash is when it is deemed to have been fully completed. And since most don't mash out any longer, even this point of stability is thereby laid open to questioning (due to the chance for the not yet deactivated enzymes to continue doing their thing until all wort has been separated from grain contact and enzymes have been deactivated by heating at the beginning of the boil). And if you sparge that tosses a monkey wrench of change into the mix, so for the sake of standardization, "wort pH" should be measured when the mash step is mystically deemed (or better, starch tested with iodine) to be complete.

With mash times ranging from 30 to 90 (or more) minutes for single infusion, and then with step and decoction mashing tossed into the mix, and with water to grist ratios all over the board (up to and including no sparge/BIAB), etc... how can anyone suggest that within such a variable ridden moving target can be found a standardized early "mash pH" sampling time?

If you were going to measure the elapsed time for a dragster on a 1/4 mile track, would you do it when the dragster is only about a quarter to perhaps a third of the way down the track? If you are doing a chemical titration to precisely determine sample concentration, would you stop titrating and then merely "project" the titration endpoint at the quarter to third of the way done point, or take the titration to completion? Etc... And by association, why on earth have we been attempting to do likewise when mashing beer and taking pH measurements?

 

[North_of_60]

I was intending to do a 20 and 30 minute pH sample but time slipped away. Although I pulled the first sample at 23 minutes it was a good 20 or 30 minutes before I tested the first sample. When it came in so high I took another, by then 55 minutes had passed. I added the final sample at 90 minutes just because it was fun to use my new pH meter.

Questions:
Is conversion still happening in the sample while it's cooling? If it is, I pulled the sample at 23 minutes but tested it at 50 minutes.
Should I filter out the grist in the sample to stop the conversion?

@North_of_60's recipe as posted is using a 3.78 qt/lb mash thickness. I point that out because I brew my Witbier recipe using BIAB and a 2.0 qt/lb mash thickness and I though that was high.

I may be misunderstanding BIAB full volume mash. This is the note on BIAB from BeerSmith: "Brew in a bag method where the full boil volume is mashed within the boil vessel and then the grains are withdrawn at the end of the mash." Does the higher water volume increase the pH?

When I lived in Alaska I made 5 gallon batches in a 7.5 gallon kettle. So my BIAB method was to mash with about 5 to 5.5 gallons. This is about 2.0 qt/lb. Then sparge the bag with 170 F water to bring the level up to about 6 and then very carefully boil. (I never had a boil over). Then after the boil I would add whatever water was necessary to bring it up to my post boil volume. Now I have a 10 gallon kettle so I use the full volume for mash and boil.

I'm thinking of going back the my old method. The beers I made in Alaska were much better than what I am getting now. I was contributing that to the water quality, not the mash volume. In Alaska I had my own 175 foot deep well. The water temperature was 42 F year around. The only thing I know about the composition is that it was high in calcium. I know this because the water kettle we kept on the wood stove was always caked with it. We also had to run vinegar through the coffee pot once every two months or so to keep it working. Visitors from the lower 48 said our water tasted better than bottled water.

Maybe it was the water or maybe it was my method that made those beers taste so much better. I used to give a lot of beer to friends and they all said how good it was. Now I'm embarrassed to even let my family taste them. My Alaska beers were great and my TX beers are mediocre at best. I got into water adjustments because I can't get a descent batch of beer down here. Just one more reason that moving to TX was a mistake.

 

[Silver_Is_Money]

Cooling the sample greatly slows down the enzymes, but they are still going to have some lesser conversion effect.

 

[ScrewyBrewer]

With mash times ranging from 30 to 90 (or more) minutes for single infusion, and then with step and decoction mashing tossed into the mix, and with water to grist ratios all over the board (up to and including no sparge/BIAB), etc... how can anyone suggest that within such a variable ridden moving target can be found a standardized early "mash pH" sampling time?

@ajdelange documented how mash pH continues to change when sampling at different time intervals during the mash. I landed on 20 minutes as the most favorable because not everyone does 90 or 60 minute mashes these days. A high diastatic power malt like domestic 2-row can convert in about 5 minutes. But the quality of the wort produced is dependant on time temperature and pH. If 90% of conversion is done in the first 5 to 20 minutes I don't see the point in waiting to sample pH much later.

If you were going to measure the elapsed time for a dragster on a 1/4 mile track, would you do it when the dragster is only about a quarter to perhaps a third of the way down the track? If you are doing a chemical titration to precisely determine sample concentration, would you stop titrating and then merely "project" the titration endpoint at the quarter to third of the way done point, or take the titration to completion? Etc... And by association, why on earth have we been attempting to do likewise when mashing beer and taking pH measurements?

To predict the elapsed time of a dragster's 1320 run I would want to know who the driver is. What the average elapsed times are in the dragster and what type of fuel it's burning. What size racing slicks and what the track and weather conditions are. I would then use the information to predict what the elapsed time should be based on past experience.

 

[ScrewyBrewer]

I may be misunderstanding BIAB full volume mash. This is the note on BIAB from BeerSmith: "Brew in a bag method where the full boil volume is mashed within the boil vessel and then the grains are withdrawn at the end of the mash." Does the higher water volume increase the pH?

No, but the thinner a mash is the more it requires water adjustments to stay within a recommended pH range. There is a direct relationship between mash pH thickness conversion time and wort quality.

 

[ajdelange]

If you were going to measure the elapsed time for a dragster on a 1/4 mile track, would you do it when the dragster is only about a quarter to perhaps a third of the way down the track?

Were I given the opportunity to place a bet based on that measurement, you bet I would. Why, because that would be a pretty good predictor of the outcome of the race just as the 20 -25 minute mash measurement is a good predictor of the outcome of the mash.

 

[North_of_60]

No, but the thinner a mash is the more it requires water adjustments to stay within a recommended pH range. There is a direct relationship between mash pH thickness conversion time and wort quality.

From the link you referenced: "A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars."

So, by using >2 quarts of mash water per pound, (3.75 qt./lb. in my case) it takes longer to complete the conversion process. Hence the 90 minute mash recommended for BIAB full volume mash.

Quoting the link again: "Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90."

Based on this, there does not appear to be a standard time for checking the pH of the mash. A 20 or 30 minute pH sample taken from a 2 qt/lb mash is going to be quite different than a 20 or 30 minute sample taken from a 3.75 qt/lb mash. I think @Silver_Is_Money is correct, the proper time to check pH is after conversion is complete.

 

[ajdelange]

From the link you referenced: "A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars."

I've noticed in others of his posts that he evidently thinks the conversion of starch to sugar is one of the acid base reactions we are talking about here. Thre's even one in this thread:

As I see this (I.E., in my opinion) I would suggest that if your mash pH was 5.71 at the very end of the mash, that is your actual mash pH, as that is when the very last traces of starches were being converted into sugars.

(C6H12O6)n --> (C6H12O6)m<n. Where's the proton exchange there?

So, by using >2 quarts of mash water per pound, (3.75 qt./lb. in my case) it takes longer to complete the conversion process. Hence the 90 minute mash recommended for BIAB full volume mash.

Maybe. But what has that to do with the pH change during the mash? What have you measured?

Quoting the link again: "Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90."

Based on this, there does not appear to be a standard time for checking the pH of the mash. A 20 or 30 minute pH sample taken from a 2 qt/lb mash is going to be quite different than a 20 or 30 minute sample taken from a 3.75 qt/lb mash. I think @Silver_Is_Money is correct, the proper time to check pH is after conversion is complete.

There is an evolving standard. It is 25 - 30 minutes in. Measurements made at that time match the predictions of good estimation software quite well and as such they are tools useful to the brewer. A program that attempted to predict end of mash pH would be pretty useless. Were I to try to write one I sure as hell wouldn't put a pH rise of 0.2 pH relative to what the chemistry predicts into it because it wouldn't match what I have observed. And it doesn't match what Martin or anyone else I know of has observed either. The implications of what Martin posted here are that if mash pH is higher than 5.4 early it will drift towards 5.4 over time i.e. decrease and it will if that's the equilibrium pH for that mash.

Here we have a case where a member who has never made a mash pH measurement except at the beginning of the mash conjecturing that there is a dramatic rise in pH at the end relative to the beginning based on a presentation that is basically trying to explain the benefits of sauermalz which presentation is riddled with glaring errors. I always try to keep an open mind but that doesn't mean that things shouldn't be questioned and in that sense it is good that this is being kicked around. The only way I can think of that mash pH would increase so dramatically over time beyond the first half hour or so is if the mash or liquor (especially if it is in the form of powder mixed in with the mash as some recommend) contains calcium carbonate. But please, let's get some measurements that support the hypothesis and then reopen the discussion.

 

[North_of_60]

There is an evolving standard. It is 25 - 30 minutes in. Measurements made at that time match the predictions of good estimation software quite well and as such they are tools useful to the brewer.

Forgive my ignorance. It seems that taking a pH sample 25 - 30 minutes into a low water to grist ratio mash that only takes 30 minutes is the end of mash. Where on a high water to grist ratio mash that requires a 90 minute mash the conversion is only 33% complete. Would not the predicted pH at 25 -30 minutes differ for each of these mashes.

What water to grist ratio are estimation software using?

Should we have a standard water to grist ratio as well as standard time for taking samples?

 

[ajdelange]

I recommended the taking of pH measurements at various times during a mash so that you can see how it assymtotically approaches an equilibrium value. I'll now recommend that you do some starch conversion tests. While the only readily available test is the iodine test and it certainly has its limits I think you will be able to see from it that conversion is much more than 33% complete after 30 minutes. I quit doing them because they always showed a complete reaction after a few minutes. The conversion reaction, like the acid base reactions, proceeds quickly at first and then slows as the reactants are consumed. This doesn't mean that you shouldn't hold the whole 90 minutes as there are other reactions going on besides the conversion reactions and these are responsible for producing the flavor and aroma compounds that make good as opposed to acceptable beers.

I wasn't aware that thicker mashes only take 30 minutes to complete. Well, per what I said above they are probably 90% complete after 10 minutes. I seem to remember some maltster publishing conversion times on his malt data sheets and that they were 10 - 25 minutes but that's a vague memory for sure. In any case, I do mostly decoction mashes so it's hard to say how long the saccharification rest is but with ales I hold an hour - to get those flavor reactions 100% complete.

Evidently you missed one of the major points of No. 12. The conversion reactions are NOT the reactions that bring about changes in mash pH. They are, however, mediated by pH and that's why we try to control it.

I have no idea what the various programs use. In my own work I depend on malt characterization parameters based on measurements of the real malts. I've standardized, for malt tests, 50 grams of malt and 100 mL of water as that represents a pretty typical mash. There is no reason to suppose that my results would be any different with 50 mL/50 g or 200 mL/50 g but I have not checked this. Were I to find that thinner mashes gave different results I would measure the malts at a higher water to malt ratio and feed that data to the program were it being used for thinner mashes.

 

[micraftbeer]

My brewing bible is Palmer's "How to Brew". It's a very humbling and misleading title as it goes into the science of brewing in great detail. Palmer recommends measuring the pH somewhere between 5 and 10 minutes into the saccharification rest. He justifies this because: 1) the pH will decrease slowly throughout the mash, and 2) conversion happens quickly and enzymes can be denatured quickly due to non-optimum pH. Of course from a practical perspective, you aren't adjusting during the mash, you have to just plan, and take notes of your results to grow your personal database of knowledge for next time.

I've also read that a lot of mash pH prediction can be go out of whack for various reasons, so they are a guideline. It seems your best bet is to pick a tool and stick with it. With notetaking on multiple batches you'll figure out when to believe it and when you want to adjust.

 

[ajdelange]

John has learned a lot about brewing science since he wrote that book. Check his "Water".

The rest of us have learned a lot too (in no small measure from helping John write that book - the water one that is). The first generation mash pH estimation programmes relied on empirically derived algorithms to estimate mash pH. We now have algorithms based on the science. There are still problems to be worked though.

 

[ScrewyBrewer]

Quoting the link again: "Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90."

Based on this, there does not appear to be a standard time for checking the pH of the mash. A 20 or 30 minute pH sample taken from a 2 qt/lb mash is going to be quite different than a 20 or 30-minute sample taken from a 3.75 qt/lb mash. I think @Silver_Is_Money is correct, the proper time to check pH is after conversion is complete.

Well, that would depend on the grain bill. Pale malts with high diastatic power will convert faster. Like a SmAsH mash using 100% Pale Ale malt which is categorized as a base malt. Malts with no diastatic power like dark crystal and roasted or flaked torrefied grains and raw cereal grains rely on the diastatic power of base malts for conversion. They will slow conversion down.

"As a homebrewer, the important thing to know is that the standard 60-minute mash gives sufficient time for almost any base malt to completely convert an all-malt mash. If you add starchy adjuncts, the mash time may need to be extended for the malts with the lowest amount of diastatic power However, your mash may convert more quickly if you are using a high diastatic power (or “hot”) malt. A mash of just American 2-row can, in some cases, convert completely in as little as 5 minutes." ~Chris Colby

I think of it this way. I once read that mash temperature should be set within the first 20 minutes of the mash. If your planning to brew a thinner higher alcohol beer by mashing at 148F but you start out at 155F you have very little time to cool it to 148F before ending up with wort that makes a fuller lower alcohol beer. The same goes for mash pH since the majority of conversion also happens within the same timeframe.

It can't hurt if you have time on a busy brewday to take pH readings beginning at 30 minutes again at 60 and again at 90 just to see how much the values change. But in my mind the majority of conversion the point when mash pH matters the most happens closer to 30 minutes.

 

[ScrewyBrewer]

Forgive my ignorance. It seems that taking a pH sample 25 - 30 minutes into a low water to grist ratio mash that only takes 30 minutes is the end of mash. Where on a high water to grist ratio mash that requires a 90 minute mash the conversion is only 33% complete. Would not the predicted pH at 25 -30 minutes differ for each of these mashes.

What water to grist ratio are estimation software using?

Should we have a standard water to grist ratio as well as standard time for taking samples?

In addition to mash thickness you also need to take into account the diastatic power of each recipe's grains. The percentage of high diastatic power grains used in the mash in combination with mash thickness pH and temperature all work together to determine the length of conversion.

 

[North_of_60]

I wasn't aware that thicker mashes only take 30 minutes to complete.

I was not aware of this either until I read in in Palmer:

"A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars." (John Palmer, How To Brew, Chapter 14, How the Mash Works)

"Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90." (John Palmer, How To Brew, Chapter 14, How the Mash Works)

http://howtobrew.com/book/section-3/how-the-mash-works/manipulating-the-starch-conversion-rest

 

[ScrewyBrewer]

I've pasted below some information from the Chris Colby article giving insight into the diastatic power for some popular grains.

"Diastatic power is usually expressed in degrees Lintner (°L) — not to be confused with degrees Lovibond, a measure of color, which is also written in shorthand as °L. Diastatic power is a function of the protein content of the malt, as enzymes are proteins, and also the relative amounts of alpha and beta amylase.

N. American 6-Row 160–180 °L
N. American 2-Row 120–140 °L
European Pilsner 90–110 °L
English Pale 80 °L
Vienna Malt 50–80 °L
Darker English Pale 40 °L
Munich Malts 20–50 °L"

 

[North_of_60]

In addition to mash thickness you also need to take into account the diastatic power of each recipe's grains. The percentage of high diastatic power grains used in the mash in combination with mash thickness pH and temperature all work together to determine the length of conversion.

I think I understand what you are saying. On my previous attempt the pH only changed 0.14 over the last 67 minutes. So, initially, if the pH falls within the 5.20 to 5.6 range during the mash I would be happy with that for a starter. Then with some tweaking maybe I can get it dialed in even closer. With so many variables affecting conversion (mash pH, water ratio, temperature, grist composition) it seems that after the science there is also an art to making good beer. Perhaps, that is why some refer to our hobby as craft beer.

Next brew day I'll use a different pH estimator and be more diligent to get samples at 20, 30, 60, and 90 minutes during the mash. I'll take another after cooling the wort to pitching temperature.​

 

[Silver_Is_Money]

Next brew day I'll use a different pH estimator and be more diligent to get samples at 20, 30, 60, and 90 minutes during the mash. I'll take another after cooling the wort to pitching temperature.

It would be particularly interesting (from a standardization standpoint) to see how this turns out for the exact same recipe you just made (including all grist components being from the same brands and sources as before, and mash water analyticals and quantities being kept the same also), but I realize that making the same recipe over and over is hard to do. I'm always tweaking something.

Given that for your most recent brew, you targeted 5.4 pH and came up with 5.71 pH at the end of the 90 min. mash (while monitoring rising pH values with the progression of time), it would be interesting to see where some of the other of such current edition spreadsheets for mash pH assistance bring your 90 minute mark mash pH to. Others will potentially disagree, but it seems to me that if 5.4 mash pH is the goal, then 5.4 pH at the end of the mash is the only possible outcome that actually meets the goal.

 

[ajdelange]

Now there are three who aren't grasping an essential point. STARCH HYDROLYSIS IS NOT AN ACID BASE REACTION. pH CHANGE IS NOT RELATED TO CONVERSION. pH CHANGE IS BROUGHT ABOUT BY ACIDS AND BASES IN THE MALTS AND WATER REACTING WITH ONE ANOTHER. NOT BY THE CONVERSION OF STARCH TO SUGAR.

But in any case the Weyermann presentation's revelation that mash pH rises to to 5.7 or 5.8 needs to be put in perspective with the much more significant revelation on slide 14 that mash pH SHOULD be between 3.2 and 4.8 depending on beer style! For years I've been mashing my wheat beers at 5.4 - 5.5. According to this slide I should have been mashing them at 4.1 - 4.4! Surprising how tasty they were given, that they should be at 4.3 and wound up at 5.7 (so I guess I'd better stop buying pH meters from Hach because all of them read 5.4-5.5 throughout my mashes). The sky is falling in! Thank god for the internet!

 

[Silver_Is_Money]

A.J., I'm confused. For a mash pH target of 5.4, would you rather that @North_of_60 see 5.71 pH at the end of 90 minutes of mashing, or 5.4 pH?

Yesterday you stated that you would not be happy to see 5.8 pH at the end of the mash. 5.71 pH is approaching 5.8 pH.

 

[ajdelange]

My pH meter was calibrated just prior to taking the first reading. When it came out higher than expected I cleaned, dried and tested it in the 6.86 solution and it read 6.86. This was repeated in the 4.01 solution and it read 4.01. The wort then retested and again read 5.57.

You are aware that you are using a NIST buffer as opposed to a NIST traceable operational buffer? That is, of course, fine if you are using a meter that accepts NIST buffers but most do not. Most of the meters that use NIST buffers are cheap knockoffs offered on Amazon but, of course, $1000 laboratory instruments accept the NIST buffers (or any buffer you like) too. So tell us about your pH meter.

 

[ajdelange]

A.J., I'm confused. For a mash pH target of 5.4, would you rather that @North_of_60 see 5.71 pH at the end of 90 minutes of mashing, or 5.4 pH?

I am too! Yesterday I would have preferred that he see 5.4 but today I see, from more careful study of the Weyermann presentation, that we should be seeing 4.2.

Yesterday you stated that you would not be happy to see 5.8 pH at the end of the mash. 5.71 pH is approaching 5.8 pH.

Yes, that's what I said and no, I would not be happy if I saw that at the end of a wheat beer mash but I've never seen that at the end of a wheat beer mash. Now I'd feel a lot better throwing out these numbers if I had my brewing logs in front of me but I don't. I am well aware that at my age relying on memory isn't always wise.

 

[North_of_60]

You are aware that you are using a NIST buffer as opposed to a NIST traceable operational buffer? That is, of course, fine if you are using a meter that accepts NIST buffers but most do not. Most of the meters that use NIST buffers are cheap knockoffs offered on Amazon but, of course, $1000 laboratory instruments accept the NIST buffers (or any buffer you like) too. So tell us about your pH meter.

No, I was not aware. My meter is a cheap Amazon knockoff. I used the buffer that was included with the meter. Does that invalidate the data I collected?

If it is a accurate in the buffers that were used to calibrate it, is it not safe to asume that it will be accurate in other solutions?

 

[North_of_60]

It would be particularly interesting (from a standardization standpoint) to see how this turns out for the exact same recipe you just made (including all grist components being from the same brands and sources as before, and mash water analyticals and quantities being kept the same also), but I realize that making the same recipe over and over is hard to do. I'm always tweaking something.

Given that for your most recent brew, you targeted 5.4 pH and came up with 5.71 pH at the end of the 90 min. mash (while monitoring rising pH values with the progression of time), it would be interesting to see where some of the other of such current edition spreadsheets for mash pH assistance bring your 90 minute mark mash pH to. Others will potentially disagree, but it seems to me that if 5.4 mash pH is the goal, then 5.4 pH at the end of the mash is the only possible outcome that actually meets the goal.

I agree that to collect relevant data one should brew the same recipe. Whether I brew this beer again Depends on how it turned out this time. I have high expectations for it but even then it will be months before I brew it again. My next is going to be an Irish Red so it will be quite different.

 

[Silver_Is_Money]

A.J., I fully agree that starch hydrolysis is not an acid/base reaction, but where we may differ is in my belief that ongoing/active starch hydrolysis is an "indicator" that the mash water has not yet permeated into the deepest reaches of the grist/kernels, and as such (for the OP's recipe) the basic (with respect to the mash pH target of 5.4) grist has not yet liberated the last of such, its basic nature. And if the mash water is acidic, and the grist is still "relatively" basic, then the acid/base reactions required to achieve mash pH equilibrium are not yet achieved. This is why I feel that the termination of saccharification (end of the mash) is a useful tool of indication to the brewer that the deepest confines of the basic (with respect to pH 5.4) malt grains have been reached by the mash water. And as such the malts reaction with the mash water should at this juncture be in static equilibrium, and therefore this is why I suggest that mash pH sampling should be justified as being most reliable at this juncture.

 

[ajdelange]

OK. But it seems that using sachharification to tell you when to read pH rather than the other way around is the reverse of what common sense dictates as it is very hard for a home brewer to detect completion of saccharification whereas it is quite easy to tell when the pH has stabilized. Now OP posted that as a BIAB mash takes 90 minutes it's only 33% complete at the end of a half hour. That is not, of course, true. It will follow an assymptotic curve just as pH does. It's essentially complete in 10 - 15 minutes. We just wait an hour with a thick mash to be sure we've got every ounce of sugar we're going to get (but I believe, its really to get flavor, head etc.). And, reasoning that lower enzyme concentration will slow conversion and proteolysis, we wait longer for a thin mash (90 min). Acid base reactions are not by and large enzyme catalyzed AFAIK. An enzyme expert might correct me on this. I'm aware of carbonic anhydrase which catalyses the extraction of water from carbonic acid but that's not an acid base reaction and doesn't happen in the pH range of interest in brewing.