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Old 06-27-2013, 01:30 AM   #1
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Default Brew Strong 5/13 Podcast

I just finished listening to Brew Strong from 5/13/2013. Palmer spoke in length about their new findings for the upcoming Water book.

It sounds like the new paradigm in Water Chemistry will basically be controlling Mash pH. It sounds like salt additions will only be used for fine tuning well developed recipes, if at all. It seems this has been a slowly developing trend that started with rejecting city water profiles, to down playing sulfate/chloride ratio, and I believe this book maybe the final catalyst to stop worrying about salt additions altogether. The switch being to controlling residual alkalinity with the use of acids for pale beers and calcium hydroxide for darker beers to reach the target 5.2 - 5.6 mash temperature range.

The most interesting topic covered involved malt acidity and malt color trends. There seems to be a maximum malt acidity occuring between 325L - 350L, which coincides with a transition in the milliard reaction color shift from red to brown. The currently proposed mechanism claims there's a maximum acetic acid concentration resulting from the millard reactions occuring in the 325L - 350L range, and that the acetic acid concentration drops off in malts higher than 350L. John even stated that Kai did some research a few years ago and found that Special B has a higher mash acidity compared to Chocolate and Black malts. However, Jamil and Palmer indicisted that there's more involved than just color with Kai's experiment that was probably attributed by malster process and/or the grain's lactobacillus levels.

The other interesting finding was AJ's titrations results from several mashes using Calcium Carbonate to increase residual akalinity to counteract the darker malts acidification effects on mash pH. AJ's findings were that CaCO3 is poorly soluble without pressurizing the water. Secondly, he found that Chalk's alkalinity impact took nearly three hours to see significant increases in residual akalinity. Apparently, Ca(OH)2 is more effective, but still takes 10-15 minutes to show increases in residual akalinity in the mash.

I'm looking forward to the book even more after listening to the podcast.

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Old 06-27-2013, 02:12 AM   #2
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The main findings with Ca(OH)2 and CaCO3 are that, and this should be no surprise, they don't deliver all the alkalinity they should because the calcium reacts with phosphate to release acid which neutralizes some of the alkalinity.

The long, long time required for carbonate reactions to take place was another finding. Lime reacts much faster. I don't think it takes as long as 10 - 15 minutes but I'd have to look at my notes.

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Old 06-27-2013, 03:08 AM   #3
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I understand that introducing calcium ions (use of Ca(OH)2 or CaCO3) in the mash is counter productive when attempting to increase akalinity due to the release of hydrogen ions in the production of calcium phosphate.

However, I am curious why the reaction kinetics are substantially faster for Ca(OH)2 compared to CaCO3 (10 - 15 minutes compared to 3 hr, per Palmer). I understand you did the testing, so feel free to update the time for the lime, if you'd like.

Either way, what are your thoughts on the substantial time difference between the two options? Was it just a solubility issue? If chalk was in solution, I would expect the carbonate ions would be scavenging free hydrogen ions to form bicarbonate and to a lesser extent, depending on pH, some carbonic acid.

Thanks for your comments and sharing your results AJ.

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Old 06-27-2013, 02:17 PM   #4
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Quote:
Originally Posted by novahokie09 View Post
I understand that introducing calcium ions (use of Ca(OH)2 or CaCO3) in the mash is counter productive when attempting to increase akalinity due to the release of hydrogen ions in the production of calcium phosphate.
Everyone should have but it seemed everyone had been mystified as to why chalk didn't deliver what it should and attributed it to it taking a long time to dissolve. When I realized part of the explanation was the calcium it was a sort of a Homer Simpson moment for me at least and the reaction to it was not exactly 'Oh yes, that's obvious!' though, like so many other things once the light comes on, it is. It should also be clear that the same thing would happen with lime but I'll admit I hadn't thought of it.

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However, I am curious why the reaction kinetics are substantially faster for Ca(OH)2 compared to CaCO3 (10 - 15 minutes compared to 3 hr, per Palmer).
Me too! I can understand (or think I understand) equilibrium processes but when the kinetics get into it I run out of steam quickly. Carbonic acid/bicarbonate/carbonate definitely have some strange properties in this regard and I'm sure they are better understood by real chemists than they are by me. We regulate blood pH in part, for example, by respiring CO2. This would not work, because of the time it takes for the reaction CO2 + H2O <--> CO2(aq) <--> HCO3- + H+ were it not for the presence of the enzyme carbonic anhydrase. Open a beer and it is still giving off gas bubbles an hour or more later. If you put even a small amount of chalk in water and bubble CO2 through it it will take forever and a day for it to dissolve completely. OTOH if you dump vinegar over chalk it fizzes up and is gone in seconds.

It was clear to me during my experiments, in which I added aliquots of chalk slurry to test mashes or solutions of phosphate salts and recorded pH, that the speed of the reaction was pH dependent. Sometimes it took minutes before pH leveled off and sometimes it took hours. Under some conditions protons were released by the calcium/phosphate reaction faster than the carbonate could absorb them so that the pH actually went down after the addition of chalk (though eventually it came back up).


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I understand you did the testing, so feel free to update the time for the lime, if you'd like.
I'm away for the summer and somehow failed to get the relevant files onto my laptop before I left so I can't look up the data but I am pretty sure that with the lime the pH settled out within a couple of minutes.


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Either way, what are your thoughts on the substantial time difference between the two options?
It's buried in the mysteries of carbonic acid system kinetics.


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Originally Posted by novahokie09 View Post
Was it just a solubility issue?
I don't think so. The pH reduction I'd see when chalk was added under some conditions tells me that it was dissolving making the calcium available to react with the phosphate.
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If chalk was in solution, I would expect the carbonate ions would be scavenging free hydrogen ions to form bicarbonate and to a lesser extent, depending on pH, some carbonic acid.
The fact that the calcium went into solution indicates that the carbonate was in solution too and, thus, what we both would expect to happen is, thus, not happening.

There is lots more to experiment with here. I was under the gun to get results to John and Colin when I did this stuff and as such am a bit nervous about its quick and widespread broadcast. Some of these findings which, at this point are really anecdotal, may wind up becoming gospel, as happens to so may bits of brewing lore, before they should.
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Old 07-19-2013, 03:48 PM   #5
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Incredibly dumb question... but if Carbonic acid is the acid being produce to acidify the mash, would it make sense to simply pre-treat mash water in a keg with CO2? If you're kegging you have a CO2 source and kegs so it might be feasible. I'm not sure of the level of acidification expected from carbonation though.

Feel free to tell me I'm a clueless noob with regards to water chemistry. just tell me WHY I am

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Old 07-19-2013, 06:51 PM   #6
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Would KOH be an alternative to raise the mash pH?

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Old 07-19-2013, 07:01 PM   #7
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Carbonic acid is not the acid that acidifies the mash. Its largely a reaction of calcium and malt phytins that react and liberate protons (acid) that acidify the mash.

When water is heated, the solubility of CO2 in the water decreases. Although most of that CO2 is in the form of carbonic acid at room temperature, it quickly reverts upon heating to release the CO2 into the water. The CO2 slowly leaves the water with the heating, but that rate increases when the water reaches a boil and the steam bubbles sparge the dissolved CO2 from the water. In the absence of boiling, stirring, spraying, or otherwise exposing more of the water to the air will speed the release of CO2 from heated water.

Another thing to remember is that the quantity of CO2 that can be dissolved into water is quite small and the amount of acid that carbonic acid can deliver is also small.

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Old 07-20-2013, 03:04 AM   #8
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Quote:
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Incredibly dumb question... but if Carbonic acid is the acid being produce to acidify the mash,
Carbonic acid isn't the acid being produced to acidify the mash. Carbonic acid is the product of the acidification. The brewer's biggest enemy in his brewing water is often alkalinity which manifests itself exclusively in the form form of sodium bicarbonate. When protons (acid) are supplied from an acid source HA the bicarbonate (HCO3-) reacts with the acid by

HA + HCO3- ---> A- + H2CO3 ---> A- + H2O + CO2

Most of the carbonic acid formed (H2CO3) quickly converts to hydrated CO2 and, at mash temperature, particularly with stirring/agitation, much of the hydrated CO2 decomposes into water and carbon dioxide gas which leaves the solution. Thus alkalinity is, by the agency of added acid, converted to water and carbon dioxide gas.

The added acid is, in continental brewing, traditionally lactic acid (from the fermentation of wort by lactic acid bacteria), in British brewing a mixture of hydrochloric and sulfuric acids and often, in American brewing, phosphoric acid.

If the water is hard (contains a lot of calcium) some acid is released by the reaction of this calcium with malt phosphate but this is usually a small contributor to the establishment of mash pH unless the water is really hard.

If dark malts are used they supply organic acids.

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would it make sense to simply pre-treat mash water in a keg with CO2?
No. Though CO2 is quite soluble in water at elevated temperature and exposure to the air the equilibrium CO2 content is small. What happens if you pour a beer into a saucepan and heat it to mash temperature?

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I'm not sure of the level of acidification expected from carbonation though.
Carbonic acid is a weak acid with a first pK of about 6.38. At that pH about half the acid molecules would yield their protons. At pH 5.38 (approximate mash pH) there will be 10 times more carbonic acid molecules that kept their first proton than molecules that released them.


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...I'm a clueless noob with regards to water chemistry. just tell me WHY I am
No idea. Probably because you haven't studied it before.
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Old 07-27-2013, 03:55 AM   #9
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>>I just finished listening to Brew Strong from 5/13/2013. Palmer spoke in length about their new findings for the upcoming Water book.

This shouldn't be new to anyone who reads these forums. I've read this type of information at least 2 years ago and probably longer.


>>It sounds like the new paradigm in Water Chemistry will basically be controlling Mash pH. It sounds like salt additions will only be used for fine tuning well developed recipes, if at all. It seems this has been a slowly developing trend that started with rejecting city water profiles, to down playing sulfate/chloride ratio, and I believe this book maybe the final catalyst to stop worrying about salt additions altogether. The switch being to controlling residual alkalinity with the use of acids for pale beers and calcium hydroxide for darker beers to reach the target 5.2 - 5.6 mash temperature range.

I don't see how this is anything new. Salts have a small impact on pH, but aren't the main way we adjust the pH of our water.
Add acid (Phosphoric or Lactic) to alter the pH.

My understanding was that salts are added for taste, not pH.

>>to down playing sulfate/chloride ratio,

Why? Not for pH but for taste. Or is Palmer saying it has little impact on the taste of the beer?


As for copying some historic water profile (like Burton) it's well known that brewers in those cities adjusted their water and didn't brew using the water right out of the river - so you shouldn't change your water to match an historical profile.


>>The other interesting finding was AJ's titrations results from several mashes using Calcium Carbonate to increase residual akalinity to counteract the darker malts acidification effects on mash pH.


Why bother adding Chalk? Just don't mash the dark grains. The latest Stout I made, I steeped the Roast Barley and kept it separate from the mash, and poured it in during the boil.



I will get the book, but it doesn't sound like it has anything new to offer.

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Old 07-27-2013, 12:28 PM   #10
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Books seldom have any thing new to offer. New findings are published in primary sources i.e. peer reviewed journals, papers presented at conferences etc. The job of the author of a technical book is to distill all the primary sources into an integrated, coherent presentation of the state of the art. You won't find a single thing in the book that hasn't been hashed over in this forum or previously published in another book or been derived from long held knowledge of chemistry and brewing practice. The value of the book is in that it is a compendium of knowledge from multiple sources presented in a way that may give readers new perspective in terms of the current environment. Today we have sauermalz on every LHBS shelves, inexpensive but functional pH meters and ready access to RO/DI water. These make the possibilities for practical brewing liquor preparation far different from what they were as little as 10 - 15 yrs ago. I am speaking of readers with familiarity with the subject here. In addition to offering new perspectives the book should also serve as a reference for them - a place to look things up. For people new to brewing water adjustment it will be, of course, much more.

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