Potential Water Pitfalls in All Grain Brewing

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ajdelange

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I am offering this thread as a Sticky based on a recent post in which a first time all grain brewer made many of the mistakes listed here. Most of these mistakes result from adherence to recommendations from old brewing references. In the last 5 years or so we have learned a lot about how to manage brewing water and slain a few sacred cows in the process.

1) Don't do anything to your water until you know what is in it. If you don't have a valid water ion content report get one from your supplier or by sending a sample to Ward Labs. In the interim use RO water from the health food store (or wherever) and follow the guidance at https://www.homebrewtalk.com/showthread.php?t=198460

2) Don't rely on pH test strips in making decisions concerning the addition of alkali or acid to mash or brewing water. They simply aren't accurate enough. Obtain a good pH meter (far and away the best) or at least get an estimate of mash pH from one of the calculators/spreadsheets.

3) Don't add alkali (chalk, bicarbonate, lime...) to mash or brew water until you have verified, preferably by measurement, that it is actually necessary. Do not rely on the beer's color for guidance on how much alkali to add. If you can't measure a test mash then use a calculator but be aware that these sometimes call for alkali additions when they are not necessary.

4) Don't use chalk as a source of alkali. It does not react fully for days and continues to add alkalinity to your wort even into the fermenter. This is not a good thing.

5) Don't rely on 'mash pH stabilizers'. These do not work. All they do is add sodium to your beer (and phosphate ions).

6) Don't assume that because a container is labeled 'calcium chloride' that it contains 100% calcium chloride nor that a container labeled 'lime' contains 100% calcium hydroxide. The former picks up water from the air (even during the brief times it is open while you are removing material from the container) and the latter picks up carbon dioxide from the air. See https://www.homebrewtalk.com/showthread.php?t=501377 for how to handle calcium chloride. Ask on Brew Science about how to handle lime if you want to use it.

7) Don't be a slave to profiles nor assume that there is an ideal water chemistry for a particular beer but rather understand that a satisfactory representation of a particular style can be had with waters that are appreciably different from one another as long as they have the same general qualities as the water on which the beer is based. The satisfaction with a style is a matter of personal preference (taste).

8)Don't assume that the ratio of chloride to sulfate ion content is a proxy for some malty - hoppy scale. There are two degrees of freedom here and you must learn what the effects of each ion on beer flavor are and adjust them to suit your tastes (or those of your customers).

I don't expect much argument about any of these except perhaps #8. The validity of the ratio persists in some people's minds. You can, of course, always keep track of the ratio (the concentration of one salt and a ratio is two degrees of freedom and as long as you are aware that there are 2 DOF or even that a large number of people think that there are 2 DOF you should be OK).

Finally a "Do": Do drop in on Brew Science from time to time where topics related to these items are all under pretty continuous discussion.

And another "Do": Do be aware that all beers require acid in some form in order to reach a mash pH in the desired range of 5.3 - 5.6 as measured at room temperature. In some cases the specialty malts can supply it but in general it will have to be supplied by the brewer usually in the form of lactic acid, phosohoric acid or acidulated malt.
 
Great guidance!

All mashing requires an acid for the mash pH to end up in the desired range. For most brewing, that means that some external acid such as lactic or phosphoric, acid malt, or roast and crystal malts will be needed.

For some brewing, the quantity of roast or crystal malts may be high and the extra acidity of those grains will supply the needed acid for the mash. In some cases, these grains may actually supply too much acid and then some form of alkalinity is needed to neutralize that excess acid. Adding alkalinity is a fairly rare requirement in brewing, but it can be needed in some darker styles.

The sulfate/chloride ratio can be a poor descriptor for brewing water taste and perception. However, it can provide some guidance when applied properly. I find that its applicable when the chloride content is generally within the range of 25 to 100 ppm.

Enjoy!
 
I've had great-tasting beer so far using water from a spring here in Montana; it is capped off at the source and piped in unaltered as the water supply for a town I used to live in. Back in the day, the same water was the foundation for beer a local brewry, and it has always been in my opinion the best water in the world.

I'm afraid to post the "stats," for fear of finding out that it's just not "right" for "quality" beer; all I know is that it's been working great for me! :mug:
 
This is great that this is a sticky outside of the brew science forum. I fell victim to 3 of the listed errors owing to the glaring gaps in my knowledge.

There should be another sticky thread however, that simply states "pH 5.2 stabilizer is junk. Do not use"

I am one, of no doubt many thousands who have purchased this product in good faith, working off the thought process that manufacturers and vendors wouldn't produce a home-brewing product so demonstrably useless and some would argue detrimental to its purported aims, and put it up for sale to the public.

Countless brewer videos show its use, all the major vendors online sell it and it is also on the shelves of many if not most homebrew stores; as is chalk.

It is analogous to doctors in the 1940's promoting the use of tobacco to sanitize ones bronchial tree. Perhaps that's a little over zealous. I just feel like such a mug for having bought the product and used the product as a total novice; (still, a novice, just lost the "total" on foot of some homework), only to subsequently be advised against it's use. Finally seeing the error of my ways after a handful of batches, I trashed it many months ago.

Just this week, I got a Morebeer catalog in the mail. In it, 1-2 pages of various products to test and tweak ones water and there, center stage is pH5.2 rendering all the other chemistry players obselete. A novice brewer,albeit an ill-informed one like myself, looks at this and says to themselves, "why would I purchase all these items when this one product does it all". A panacea for all of life's water chemistry ailments if you will.

Let the word get out. Let there be a HBT banner article, a blimp with neon lights over next years Bluebonnet (insert your own states/country's big homebrew shindig), a popup warning on the website, a flyer campaign or just a couple of unshaven strangely aromatic oddballs shouting it from street-corners. It is worse than useless! Don't buy it! Testify!

Whew, three exclamation points in one paragraph, I guess it's no more Biermuncher's Centenial Blonde for me. Maybe one of Yooper's Oatmeal Stouts before I put the belligerent head down.

In summary, a huge thanks to @AJDelange and @Mabrungard for all their great work and tireless efforts, to educate, at times, what must seem like a non-attentive class of home brewing miscreants. I like many am deeply indebted to you both.

As a side note. Today I created calcium chloride solution of known concentration to be used as a water addition. The more you know......
 
We often say it works great if you don't own a pH meter.

Don't worry, I won't click the like button again.

Used my freshly calibrated Hach Pro+ again today and Bru'n Water.

The predicted pH in the spreadsheet were very similar to measured mash pH. Targeting 5.4 for a Munich Helles

Bru'n Water predicted 5.4
Mash sample 25mins into a mash 5.33 at 25.3C
 
We often say it works great if you don't own a pH meter.

I am stealing this to use!! lol

Anyway... Gavin... I feel the same way. i bought the 5.2 at one point as well. Whats even better is when i here people in my brew club talking about how great it is. LMAO. I tried to tell them that i TESTED it with my ph meter but some people still have it stuck in their head that you need it. Oh well.

AJ, thanks for the great sticky. as usual your advice is rock solid. FTR adn anyone else that hasnt tried yet, If this si a topic you are interested in, AJ's advice about getting a PH meter is in dispensable. There is no way you can acurately check all this without one.

what i have been following for my water practices is the Brun water spreadsheet (the paid version is absolutely worth the money IMO) and my ph meter. for the most part, my ph has been pretty close (my water table changes sources on a regular basis), and i have been using mostly just a little calcium chloride, and lactic acid. The info in the brewing water chemistry primer (also by AJ) is a great place to start and not get over whelmed either!

Cheers! :mug:
 
I'd like to remind people that in certain areas you may need to have your water checked several times a year, since the source of household water can change seasonally.

I had my water checked a few years ago and it's well past time again. Even areas that are very stable might fluctuate over longer periods of time.
 
I'd like to remind people that in certain areas you may need to have your water checked several times a year, since the source of household water can change seasonally.

I had my water checked a few years ago and it's well past time again. Even areas that are very stable might fluctuate over longer periods of time.

That's a good point and one reason it is useful to consider getting not only a brewer's report; I got a one from Ward Labs, but also one from your local water authority. I found my city people to be very helpful and have been able to get it more than once. I can compare the city's values over the course of the year to see if any notable changes are present, thus prompting the possible need for a new water report from Ward Labs.

Thus far I have found that people working for the city are only too happy to provide what information they have. I also found the averaged numbers from the information with regard to the water from the three taps supplying my home, was not too dissimilar from the actual numbers provided by Ward Labs.
 
I'd like to remind people that in certain areas you may need to have your water checked several times a year, since the source of household water can change seasonally.

Good recommendation. However, you may not have to have a full water test conducted. The main concern with variability is its effect on mash pH and that is due to hardness and alkalinity variation. Relatively inexpensive hardness and alkalinity test kits for aquarium use could be good additions to your brewing kit. Of course, this assumes that flavor ions such as Na, SO4, and Cl don't vary too much.

Another way to quickly gauge if your water has varied is to check with a TDS meter. If there are periods when the water has higher or lower TDS, that could be a good time to collect a sample for testing. With those full test results, you can get an idea of how the ionic content varies with respect to TDS. This is imprecise, but if your water company has a source with high ionic content and another with low content, then you will be quickly forewarned of the change.
 
So with regards to water chemistry fluctuations, I have a question. It seems as the discussion thus far has focused on municipal water supplies.
How much would well water fluctuate?
 
I'd like to remind people that in certain areas you may need to have your water checked several times a year, since the source of household water can change seasonally.

I had my water checked a few years ago and it's well past time again. Even areas that are very stable might fluctuate over longer periods of time.

Good idea. Particularly if your water comes from a well. It's my guess that water would have a lot more dissolved everything if it's a dry vs a wet period. Also, my municipal water pulls from 8 different wells. I'm guessing it changes drastically depending on the well they're pulling from
 
Good recommendation. However, you may not have to have a full water test conducted. The main concern with variability is its effect on mash pH and that is due to hardness and alkalinity variation. Relatively inexpensive hardness and alkalinity test kits for aquarium use could be good additions to your brewing kit.

Do you mean something like this?

https://www.amazon.com/dp/B003SNDDAU/?tag=skimlinks_replacement-20

What would be the products I would likely use to"fix" hard water? Not sure if there is one quick and easy answer to that question.
 
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So with regards to water chemistry fluctuations, I have a question. It seems as the discussion thus far has focused on municipal water supplies.
How much would well water fluctuate?
It can fluctuate quite a bit. Here are some random data from my well (200')
Date Alkalinity PO4 NO3-N
11/06/14 111 0.64 4.95
11/13/14 93.8 0.41 4.82
11/24/14 135 0.33 4.14
12/08/14 122
11/29/14 145
04/26/15 134
05/22/15 69.325 0.16 4.73
05/26/15 82.3 0.15 4.48
05/29/15 120 0.11 4.17

n 9 6 6
Average 112.4916667 0.3 4.548333333
Standard Deviation 25.73739983 0.203371581 0.341374672
Max 145 0.64 4.95
Min 69.325 0.11 4.14
Range 75.675 0.53 0.81

These are parameters I can measure quickly and easily. You can assume the hardnesses vary with the alkalinities. Sulfate and chloride are pretty steady as are, evidently, the phosphate and nitrate.

Hardness is not something that one usually sets out to fix but brewers do try to fix high alkalinity and in two of the most popular methods (boiling and lime treatment) an equivalent amount of hardness is removed for each unit of alkalinity removed.
 
I just bought property with a well that hasn't been used for years. What has to be done to get an accurate test sample for the well?

You should get it tested anyway just to make sure it is healthy to drink. Your state department of health should have information on well testing. They may even send a free test kit. Otherwise you can buy test kits. Plus you can send a sample to Ward Labs for brew water testing.
 
Water is pretty good in the Willamette Valley and my only concern is the Summer-Fall higher levels of chloramine.

My first few batches of home brew tasted fine to excellent to me using water directly from the tap. However, after a recommendation from the local Brew Supply store, I began using a carbon water filter (same type that I use with the RV). I just run my tap water (8 to 10 gallons) very slowly through the filter into my brew pot the night before I start a brew.

Perhaps, my palate is not educated enough to pick up imperfections in my beer but, so far, I am quite happy with all but two of my ten batches, and those were "carbing" problems. My friends also seem very happy with my beer.
 
I don't think it can ever be overstated that, "You can't know for sure unless you actually measure."
 
Water is pretty good in the Willamette Valley and my only concern is the Summer-Fall higher levels of chloramine.

My first few batches of home brew tasted fine to excellent to me using water directly from the tap. However, after a recommendation from the local Brew Supply store, I began using a carbon water filter (same type that I use with the RV). I just run my tap water (8 to 10 gallons) very slowly through the filter into my brew pot the night before I start a brew.

Perhaps, my palate is not educated enough to pick up imperfections in my beer but, so far, I am quite happy with all but two of my ten batches, and those were "carbing" problems. My friends also seem very happy with my beer.
Carbon filters are very inefficient at removing chlorine/chloramine. You would be much better off just adding 1/2 a campden (potassium metabisulfite) tablet per 10 gal of brewing water. Sitting overnight (uncovered) should allow the chlorine to dissipate, but not chloramine.

Brew on :mug:
 
I always use bottled - I can get a decent 5L bottle of English or Scottish spring water for £2 at Asda - even cheaper at budget supermarkets and haven't had a nasty brew yet
 
Would you need acid if using distilled water for a pale beer? Seems like the calcium added from calcium sulfate and chloride would be enough to lower the pH right?
 
Would you need acid if using distilled water for a pale beer? Seems like the calcium added from calcium sulfate and chloride would be enough to lower the pH right?

It can be. If you use the Pale Ale profile in Bru'n Water, its high calcium and magnesium additions drive down the wort pH too much and the mashing water needs a bit of alkalinity in it to avoid that excessive pH drop. However, if your Ca and Mg additions are modest, you could achieve a desirable mash pH without an acid addition when starting with RO or distilled water.
 
Calcium and magnesium have a small effect on mash pH. Everyone seems to grab onto Kolbachs observation that x amount of calcium reduces pH by y pH units but few seem to notice that this observation refers to knockout rather than mash and additional calcium is precipitated in the boil. A more sophisticated approach is to consider Kolbach's other observation in that same paper to the effect that 3.5 equivalents of calcium neutralize 1 mEq of alkalinity and 7 mEq of magnesium do the same. By proceeding in this way we can take mash buffering into account rather than just relying on Kolbach's pH observations fixed to the kinds of beers he brewed. Again this is at knockout so the numbers for the mash must be less than these. Assuming half the reaction take place in the mash and half in the kettle we would expect it to take 7 mEq of calcium and 14 of magnesium to neutralize 1 of alkalinity. Plug those numbers into a spreadsheet and I think you will find it takes a lot of calcium to appreciably shift pH by itself. I'm not saying it doesn't happen but I do say you should not rely on calcium for pH adjustment. That's what we have sauermalz and sauergut for.
 
Unfortunately, AJ is stuck on this myth that the Kolbach effect isn't as effective as stated in the original paper. With literally hundreds of pH trials in mashes with fairly high calcium content, I can assure anyone that the Kolbach effect still holds true to a large degree. Bru'n Water does properly account for the pH depression created by calcium and magnesium addition.
 
It is as effective as stated in the paper - at knockout. To say that one sees the same depression in the mash as one does at knockout is to say that no calcium precipitation takes place in the kettle. Is that really what you want to say?
 
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I am offering this thread as a Sticky based on a recent post in which a first time all grain brewer made many of the mistakes listed here. Most of these mistakes result from adherence to recommendations from old brewing references. In the last 5 years or so we have learned a lot about how to manage brewing water and slain a few sacred cows in the process.

1) Don't do anything to your water until you know what is in it. If you don't have a valid water ion content report get one from your supplier or by sending a sample to Ward Labs. In the interim use RO water from the health food store (or wherever) and follow the guidance at https://www.homebrewtalk.com/showthread.php?t=198460

2) Don't rely on pH test strips in making decisions concerning the addition of alkali or acid to mash or brewing water. They simply aren't accurate enough. Obtain a good pH meter (far and away the best) or at least get an estimate of mash pH from one of the calculators/spreadsheets.

3) Don't add alkali (chalk, bicarbonate, lime...) to mash or brew water until you have verified, preferably by measurement, that it is actually necessary. Do not rely on the beer's color for guidance on how much alkali to add. If you can't measure a test mash then use a calculator but be aware that these sometimes call for alkali additions when they are not necessary.

4) Don't use chalk as a source of alkali. It does not react fully for days and continues to add alkalinity to your wort even into the fermenter. This is not a good thing.

5) Don't rely on 'mash pH stabilizers'. These do not work. All they do is add sodium to your beer (and phosphate ions).

6) Don't assume that because a container is labeled 'calcium chloride' that it contains 100% calcium chloride nor that a container labeled 'lime' contains 100% calcium hydroxide. The former picks up water from the air (even during the brief times it is open while you are removing material from the container) and the latter picks up carbon dioxide from the air. See https://www.homebrewtalk.com/showthread.php?t=501377 for how to handle calcium chloride. Ask on Brew Science about how to handle lime if you want to use it.

7) Don't be a slave to profiles nor assume that there is an ideal water chemistry for a particular beer but rather understand that a satisfactory representation of a particular style can be had with waters that are appreciably different from one another as long as they have the same general qualities as the water on which the beer is based. The satisfaction with a style is a matter of personal preference (taste).

8)Don't assume that the ratio of chloride to sulfate ion content is a proxy for some malty - hoppy scale. There are two degrees of freedom here and you must learn what the effects of each ion on beer flavor are and adjust them to suit your tastes (or those of your customers).

I don't expect much argument about any of these except perhaps #8. The validity of the ratio persists in some people's minds. You can, of course, always keep track of the ratio (the concentration of one salt and a ratio is two degrees of freedom and as long as you are aware that there are 2 DOF or even that a large number of people think that there are 2 DOF you should be OK).

Finally a "Do": Do drop in on Brew Science from time to time where topics related to these items are all under pretty continuous discussion.

And another "Do": Do be aware that all beers require acid in some form in order to reach a mash pH in the desired range of 5.3 - 5.6 as measured at room temperature. In some cases the specialty malts can supply it but in general it will have to be supplied by the brewer usually in the form of lactic acid, phosohoric acid or acidulated malt.

Wow, I must be lucky. Been brewing BIAB for a number of years and have never had my water checked for anything other than temp. Water comes from the City from a 1600 deep well in the mountains above my home. This water has been filtered by lava rock as it slowly works it's way down thru the mountain to the low water table.

Can't say I've ever had a bad beer unless there was an infection.
 
This is great that this is a sticky outside of the brew science forum. I fell victim to 3 of the listed errors owing to the glaring gaps in my knowledge.

There should be another sticky thread however, that simply states "pH 5.2 stabilizer is junk. Do not use"

I am one, of no doubt many thousands who have purchased this product in good faith, working off the thought process that manufacturers and vendors wouldn't produce a home-brewing product so demonstrably useless and some would argue detrimental to its purported aims, and put it up for sale to the public.

Countless brewer videos show its use, all the major vendors online sell it and it is also on the shelves of many if not most homebrew stores; as is chalk.

It is analogous to doctors in the 1940's promoting the use of tobacco to sanitize ones bronchial tree. Perhaps that's a little over zealous. I just feel like such a mug for having bought the product and used the product as a total novice; (still, a novice, just lost the "total" on foot of some homework), only to subsequently be advised against it's use. Finally seeing the error of my ways after a handful of batches, I trashed it many months ago.

Just this week, I got a Morebeer catalog in the mail. In it, 1-2 pages of various products to test and tweak ones water and there, center stage is pH5.2 rendering all the other chemistry players obselete. A novice brewer,albeit an ill-informed one like myself, looks at this and says to themselves, "why would I purchase all these items when this one product does it all". A panacea for all of life's water chemistry ailments if you will.

Let the word get out. Let there be a HBT banner article, a blimp with neon lights over next years Bluebonnet (insert your own states/country's big homebrew shindig), a popup warning on the website, a flyer campaign or just a couple of unshaven strangely aromatic oddballs shouting it from street-corners. It is worse than useless! Don't buy it! Testify!

Whew, three exclamation points in one paragraph, I guess it's no more Biermuncher's Centenial Blonde for me. Maybe one of Yooper's Oatmeal Stouts before I put the belligerent head down.

In summary, a huge thanks to @AJDelange and @Mabrungard for all their great work and tireless efforts, to educate, at times, what must seem like a non-attentive class of home brewing miscreants. I like many am deeply indebted to you both.

As a side note. Today I created calcium chloride solution of known concentration to be used as a water addition. The more you know......
Amen Brother
 
Basic question: Should the pH of the water or the pH of the mash be measured, since adding grain to the water will alter the pH depending on the grain. Meaning, do you start the mash and then measure pH and adjust accordingly or adjust the pH of the strike water prior to mashing?
 
Chasing mash pH in real time is a losing proposition in many ways (temperature maintenance a big one). The goal is to have calculated the minerals/salts and acid required - given the grain bill and water volumes needed - in advance, so hopefully if there is any pH error it's small.

I use Bru'n Water for this, but there are other tools.

I take a pH reading 10 minutes after dough-in (then cooled to 68F).
If the mash pH was over or under I note it for the next time I brew that recipe...

Cheers!
 
Chasing mash pH in real time is a losing proposition in many ways (temperature maintenance a big one). The goal is to have calculated the minerals/salts and acid required - given the grain bill and water volumes needed - in advance, so hopefully if there is any pH error it's small.

I use Bru'n Water for this, but there are other tools.

I take a pH reading 10 minutes after dough-in (then cooled to 68F).
If the mash pH was over or under I note it for the next time I brew that recipe...

Cheers!
Thank you for that information. I did wonder how it would be possible to have an acceptable pH range especially if using multi step infusion. It seems that one does not want to wait 10 minutes to know the pH when using the multi step method. So I intend to begin pH measurement after dough in, unless pH is not as important for the protein rest step
 
Unfortunately, mash pH does not stabilize for about 20 minutes so we really don't have much choice in the matter. You can take readings before 20 minutes and with a little practice predict pretty closely from a 10 minute reading what the 20 minute reading will be but to get the equilibrium mash pH (or close to it) you will have to wait 20 minutes or more. The object is, as stated in #32, to have made additions that will get you close to the desire pH as verified with a test mash. Small errors in the equilibrium pH should be noted for adjustment of the amount of acid (or base) used to set pH in future brewings of this beer. Large errors should be corrected and while they will not completely remove problems that have been caused by improper mash pH fully at least you will be going into the kettle and fermenter with pH in the right range.
 
I settled on testing pH on 15-minute intervals during the mash. I find that the first pH result at 15 minutes into the mash is only a few hundreths off the following measurement results. When I used to collect at the 10 minute mark, the difference was larger. I'd say that AJ's recommendation for about 20 minutes is close enough.
 
Ok, 20 minutes. Given that there is an initial protein rest step for 10 minutes at 122 F, what should be done for pH there? Or will it not affect the later steps where the temperature is raised?
 
Ok, 20 minutes. Given that there is an initial protein rest step for 10 minutes at 122 F, what should be done for pH there? Or will it not affect the later steps where the temperature is raised?

If you've applied the measures recommended from a competent brewing water chemistry tool, the pH should be close enough. I don't chase pH after I've applied those measures. I just monitor pH and log the results in my record so that I can alter my target in future brews.
 
Ok, 20 minutes. Given that there is an initial protein rest step for 10 minutes at 122 F, what should be done for pH there? Or will it not affect the later steps where the temperature is raised?
A malt's influence on mash pH depends on its DI mash pH and a couple of buffering terms which describe its resistance to pH change as protons are added (from acid) or taken away (absorbed by a base). The DI pH depends on temperature. The buffering terms less so. Thus when a malt's acid/base characteristics are measured it is done at some temperature reasonably representative of mash conditions. At the same time the rate of change of DI mash pH with temperature is measured. In order to determine the amount of acid needed for a particular malt for a particular pH one uses the formula a*(pH - pHDI) + b*(pH - pHDI)^2 + c*(pH - pHDI)^3 in which pH is the pH of interest (target pH), pHDI the DI mash pH and a, b and c the buffering coefficients. Strictly speaking this malt characterization is accurate only for the temperature at which the measurements of a, b, c and pHDI were made. But as the expansion is about pHDI we can obtain the proton requirement (or surfeit) at any temperature simply by changing the pHDI value by the amount of temperature glide (as I like to call it). Thus, from measurements ( a complete set would be pHDI, a, b, c, T at which these were measured and the glide i.e. rate of change of pHDI per degree temperature) made at, say 40 °C we can obtain the deficit at 50 °C (122 °F), 25 °C (room temperature) or any other temperature of interest. Temperature of interest is an input parameter to a spreadsheet that implements the pH control/prediction algorithm correctly. Unfortunately, none do this but then none that I am aware of implement the deficit formula properly either.

Now since one is going to check mash pH at room temperature the obvious temperature to enter into the calculator is room temperature. Thus one could make a proper spreadsheet or calculator which implements the formula properly by shifting each malts pHDI to room temperature if it were understood that all estimated pH's are for room temperature and, in the control mode, all acid additions are for target pH as measured at room temperature.

As pHDI, a, b, c, T, and ∂pHDI/∂T are all measured 25 minutes after the sample is 'doughed in' it also has to be understood that results obtained using them only strictly apply to measurements of mash pH made 25 minutes after strike. The idea here is that if the glide theory reasonably represents reality (and it appears to but this does need to be investigated further) it doesn't matter if you dough in in the cold, at a ß-glucan rest temperature, at a protein rest temperature, or at a saccharification rest temperature.
 
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Went back to the bible (John Palmer). Also looked at a few other sites. Best to adjust pH after doughing-in the mash. No one really knows in advance what will happen to pH when grains are added unless one has the experience. Since I do not, The basic approach will be to measure pH after grain addition to strike water and have something on hand to adjust it if needed. Yes, a water report is a good idea to get. I think the bottom line is that one can make 'good' beer without necessarily fretting over pH, but it would be a lot better beer if pH is paid attention to and one knows the composition of the water being used. The commercial breweries are certainly aware! There are so many possible grain combinations that of course pH should be measured after grain and water are well mixed. Since this particular recipe I have calls for the option of multi-step infusion (and I am going to try it), I will probably be constantly monitoring pH especially the first protein rest step.
 
The problem with the approach you are proposing to follow is that by the time you get a stable mash pH reading (20 - 25 min), calculate the correction needed (how will you do that if you don't know the buffering?), measure out the acid or base add it to the mash and get it mixed in it is really too late to obtain the major benefits of proper mash pH (but it is better than doing nothing). There is a simple way around this, however, and that is to mash a small portion of grains using scaled water treatment. If you miss your target, try again with a small correction to the acid amount. From the change in pH brought about by the change in the amount of acid you can calculate the buffering and thus the amount of acid required to hit the target. Scale that back up to the full mash and proceed. This is some extra work but well worth it. As you note, with experience you won't need the test mash. Your notes from previous brewing of this beer will direct you though you may still make some small changes based on those notes. If your water is stable (use RO or the 0 effective alkalinity method to insure that it is) seasonal variations in the malts shouldn't have much effect.
 
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