Construct a dry food grade pH buffer

Not a chemist but the pH5.2 threads have me curious if it's even possible to construct a dry food grade buffer to a specific pH within the recommended mash range 5.2-5.6? Are the necessary acids even able to be dried? Are they stable in such a state?

(I know the theory of a one size fits all buffer is flawed but just humor me anyway.)

Theoretically you ought to be able to start with a citric acid solution, add sodium hydroxide to it until the pH hit 5.2 and then evaporate the water. The result would be a mix of mono and dibasic sodium citrate which ought to make a better buffer than a mix of phosphates because citrate has a pK, 4.77, which is within 1 unit of desired mash pH's.

Or you could obtain mono and dibasic food grade sodium citrate salts and mix them in the proper ratio (1:2 for pH 5.4; 1:1.29 for pH 5.2). As with the phosphate buffer you would introduce a lot less citrate and no sodium if you use the acid instead of the salts.

Ahh yes, citric acid and lye. I kept searching for sulfuric/phosphoric which ends up with some pretty nasty stuff unless you're a plant.

Makes me wonder why liquid buffers (a buffer pouch) haven't been developed/marketed.

I assume you are kidding here. pH buffer pouches are pretty popular:
http://static.coleparmer.com/large_images/35653_02_2.jpg

I'm referring to a food grade magic buffer pouch that I can add to my mash to buffer it at the desired pH. One company has dry ones based on LoviBond.

http://www.northernbrewer.com/shop/...s/salts-finings/water-treatment/accumash.html

esahlong said:

I'm referring to a food grade magic buffer pouch that I can add to my mash to buffer it at the desired pH. One company has dry ones based on LoviBond.

http://www.northernbrewer.com/shop/...s/salts-finings/water-treatment/accumash.html

Click to expand...

Some people report that the 5.2 mash stabilizers either don't work all that well, or are largely unnecessary. I can't remember which. Just FYI if you are interested in researching further.

You're right, they don't work and they don't work very well.

My proposition is that if a liquid version was developed, one could include actual acid and eliminate some of the sodium.

For example, using the Lovibond scheme, one would include an acid pouch and a salt pouch such that when used with RO/DI water it would stand a chance at working as expected.

esahlong said:

I'm referring to a food grade magic buffer pouch that I can add to my mash to buffer it at the desired pH. One company has dry ones based on LoviBond.

http://www.northernbrewer.com/shop/...s/salts-finings/water-treatment/accumash.html

Click to expand...

I actually have some opportunities for investments involving well known bridges in key metropolitan areas if you are interested.

ajdelange said:

I actually have some opportunities for investments involving well known bridges in key metropolitan areas if you are interested.

Click to expand...

You're right, those don't work very well.

From a marketing, product development perspective, if one had an acid pouch and a salt pouch for the various lovibonds, it would certainly be useable especially with a spreadsheet and/or pH Meter.

Seriously, though, if I can be for a minute or two, check the ingredients in these packets: phosphate buffers, gypsum, calcium chloride, epsom salts, bicarbonate and carbonate. It is well known (or I thought it was well known by now) that you can't formulate brewing water based on the color of the beer you want to brew, you cannot adequately buffer a mash to a reasonable pH using phosphate buffers and you should not, except under relatively unusual circumstances, add alkali to brewing water.

ajdelange said:

Seriously, though, if I can be for a minute or two, check the ingredients in these packets: phosphate buffers, gypsum, calcium chloride, epsom salts, bicarbonate and carbonate. It is well known (or I thought it was well known by now) that you can't formulate brewing water based on the color of the beer you want to brew, you cannot adequately buffer a mash to a reasonable pH using phosphate buffers and you should not, except under relatively unusual circumstances, add alkali to brewing water.

Click to expand...

But it's patented!!!!:cross:

Or so it says, I couldn't find any patents for selling pre-packaged brewing salts

ajdelange said:

Seriously, though, if I can be for a minute or two, check the ingredients in these packets: phosphate buffers, gypsum, calcium chloride, epsom salts, bicarbonate and carbonate. It is well known (or I thought it was well known by now) that you can't formulate brewing water based on the color of the beer you want to brew, you cannot adequately buffer a mash to a reasonable pH using phosphate buffers and you should not, except under relatively unusual circumstances, add alkali to brewing water.

Click to expand...

Forget about pH5.2, buffers, phosphates, ingredient packets, etc..

Think acid pouch and salt pouch (no buffering salts, just normal water salts).

Don't certain spreadsheets operate off of a lovibond principal?

Here's your pH5.4 Lovibond 6 packet.... etc...

I'm not saying it's accurate, practical or even useful, but from a marketing/product perspective one would think that's the approach that the makers of some these "buffers" would have taken.

esahlong said:

Don't certain spreadsheets operate off of a lovibond principal?

Here's your pH5.4 Lovibond 6 packet.... etc...

I'm not saying it's accurate, practical or even useful, but from a marketing/product perspective one would think that's the approach that the makers of some these "buffers" would have taken.

Click to expand...

Only in the broadest sense can wort color be used to drive mineral and acid adjustments...and they would not be very precise. For instance, Bru'n Water presents some water profiles that are wort-color based and serve as a STARTING POINT, but the actual final water adjustments have to be made in conjunction with the actual grains used in the recipe and their approximate acidity characteristics.

I haven't done much with water chemistry in my brewing, but my impression was that water adjustments are made to hit a particular style (e.g. "Burtonized" water for English pale ales/IPAs) or to fix any issues (high carbonate, low sulfate, etc) in your current source of water.

This is the first time I've heard of changing water profiles for beer color...I wonder if it is a "the tail wags the dog" phenomenon because Bru'n water takes it into their calculations?

broadbill said:

This is the first time I've heard of changing water profiles for beer color...I wonder if it is a "the tail wags the dog" phenomenon because Bru'n water takes it into their calculations?

Click to expand...

Then you haven't been around long. A few years back everyone thought that the design of a brewing water ion profile was driven by color. I think John Palmer probably gets the credit for this concept as it was in one of his books (which included a color based nomograph from which you would calculate how much chalk to add). Time and knowledge advance and the idea that color is a design parameter has for the most part faded except in the broadest sense (as Martin says in #13) nor do we add chalk to our beers except where pH estimation or measurement indicates it to be necessary (beers with lots of high kilned malts).

ajdelange said:

Then you haven't been around long. A few years back everyone thought that the design of a brewing water ion profile was driven by color. I think John Palmer probably gets the credit for this concept as it was in one of his books (which included a color based nomograph from which you would calculate how much chalk to add). Time and knowledge advance and the idea that color is a design parameter has for the most part faded except in the broadest sense (as Martin says in #13) nor do we add chalk to our beers except where pH estimation or measurement indicates it to be necessary (beers with lots of high kilned malts).

Click to expand...

thanks for the lit review professor. as I said, I haven't really explored the topic of water chemistry fully.

Cream of tartar is a food-grade acid buffer, but its pH is about 3.5. I don't know if that's useful or not (besides as a cheap pH meter calibrating solution)

You are most welcome. But more important is the fact that we don't in fact add chalk to our beers even when measurement shows it to be necessary. We add a different alkali because there are several problems with chalk (also a fairly recent finding).

z-bob said:

Cream of tartar is a food-grade acid buffer, but its pH is about 3.5. I don't know if that's useful or not (besides as a cheap pH meter calibrating solution)

Click to expand...

Cream of tarter is the monobasic potassium salt of tartaric acid which has pKs of 2.98 and 4.34 and as such exhibits pH of ~(2.98 + 4.34)/2 = 3.66. As is always the case when half way between the pK's the buffering is worst. OTOH if one were to take a cream of tartar solution and add potassium hydroxide to it until the pH reached 4.32 he would have a buffer though probably not a terribly good one as those pKs are pretty close. Adding more KOH to reach mash pH would, for pH < 5.32, satisfy the "stay within 1 pH of a pK" rule but again the buffering wouldn't be that great as the pKs are close. The broad observation is that in effect a buffer consisting of a mix of Hn-1A- and Hn-2A-- is really using Hn-1A- as an acid to pull the mash pH down. You aren't going to get much regulation of pH unless there is a lot of Hn-1A- relative to whatever else is in the mash and setting its pH. That means it takes a lot of the buffer (with the attendant cations) to get good buffering action. It is much more effective to use HnA as the acid and there are no cations.

Apropos of nothing - Rolaids would be an interesting salt addition. They would add calcium (via chalk) and magnesium and then soothe your stomach after a pint. Seems like a win-win. N_G

ajdelange said:

...you cannot adequately buffer a mash to a reasonable pH using phosphate buffers ....

Click to expand...

Some more reflection on this subject has led me to think that while the statement above is certainly true with respect to ortho-phosphate buffers it may be less so with pyro-phosphate ones. A little digging turns up sodium pyro phosphte (also known as sodium acid phosphate) that is fairly commonly used in the food industry where a dry acid is needed. The graph shows the buffering capacities of a mmol of each of a ortho and pyro phosphate salt near mash pH. As it shows, the pyro phosphate has quite a bit more than ortho phosphate in the 5 - 6 region. The pyro phospahte, with its pK at 6.68, would violate the buffer rule for any mash pH < 5.68 but not by too much.

Practically speaking, a typical ale mash using 88% MO and 12 % 40L crystal using 1.4 qts of water with hardness 1.5 mVal and alkalinity of 2 mVal (100 ppm as CaCO3) could be set to pH 5.5 with a sodium load of 81 mg/L in the mash water using disodium pyrophosphate. That's still quite a bit but much better than with the ortho salt. And it would get diluted down somewhat in the beer.

So this isn't the magic powder we all seek but it does represent some improvement over the usual phosphate. Perhaps this is the basis of the new product referred to earlier.

Thinking still further on this I have been asking myself whether home brewers shouldn't be adding sodium acid phosphate to the list of 'acids' we consider for mash pH control. I've put it in my mash pH prediction spreadsheet. It is commonly used in the food industry and is GRAS but I can't find any source of small quantities e.g. health food stores don't seem to sell it nor does Duda Diesel. Looking at the curves in the previous post it really isn't that great but it could conceivably be used where the proton deficit to be overcome is modest and the water low in sodium.

So where to get it becomes the major question. The potential answer: from 5.2! This is mostly monobasic sodium phosphate which, if heated to 169 °C should yield up water and convert to sodium acid phosphate. Maybe we have answered the question 'What is 5.2 good for?'. I'm not near my lab and can't try this so I don't know the practical aspects of it. There is, in 5.2, some dibasic sodium phosphate as well. The temperature required to convert that to pyrophosphate is much higher (500 °C) so its alkalinity will remain to offset the acidity of the disodium pyrophosphate generated by heating the monobasic salt.

Interesting!

Would that sodium acid phosphate be hygroscopic and revert back to the base salt if exposed to moisture in the air?

That's a good question. There are hydrated forms (a hexahydrate in particular) but I think it safe to assume that if you just take it out of the oven where it has baked at 350 °F for an hour or so that it will be the anhydrous form. The question is how long will it take to pick up water from the air. Were I at home I would try this roasting and then put some on the balance monitoring for weight increase over time. I'd also then do a titration to see how acidic the baked stuff really is. This will have to wait until the fall.

It would not revert to the ortho form in becoming hydrated at room temperature (AFAIK) but it will if boiled. This is part of a 'total phosphate' test. This is potentially a plus for brewers because that will happen in the kettle where the orthophosphate would convert thus insuring no weird phosphate in the beer and it would also, to some extent, precipitate with calcium as it normally does thus keeping pH low (i.e. the precipitation would offset the loss of acidity when the less alkaline pyro form is converted to the more alkaline ortho). All theoretical considerations at this point.