pH Stabilizer Recipe

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althalos

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Hey all-
I was suddenly intrigued by a product I had passed up for years without a second thought. It is supposed to stabilize your strike/mash water to a pH of 5.2. I hadn't given pH in mashing a thought until I listened to some brew strong podcasts and did some research. With a triple decocted doppelbock in the works, I thought it may be a good idea to stabilize the pH. I had read that a certain pH stabilizer commercially sold (ahem) uses phosphate buffers. Sodium phosphate makes an excellent buffering system that is supposed to work between 5 and 8, and I had the reagents in the lab I work in. An online calculator quickly reveals the amounts of reagents to add to achieve the following:

For a 5mM (milliMolar) final buffering solution:
25.57g Monobasic Sodium Phosphate, Monohydrate
1.08g Dibasic Sodium Phosphate, Heptahydrate
Dissolve the above in 100ml final volume, split into two 50ml aliquots.
Each 50ml aliquot will treat 5 gallons of water to yield a final buffer concentration of around 5mM.

I chose 5mM as this yielded around a tablespoon of dry reagent per 5 gallons. Ideally, 10mM may have been a better idea, but I figured this was just an aid, as the phytases in the mash should already be doing a good enough job. pH of the mash stayed around 5 the entire process (as measured by the pH paper [I know they are slightly inaccurate]).

Yes, I realize it's probably not necessary for most water, but some people would also argue that fly sparging is not necessary while batch sparging exists; do with this information what you will. The commercial example probably wouldn't exist without worrywarts like me.

Update: Did some price checking. It's cheaper to buy the commercial version.
 
So we talk about adding 5 grams of one salt or another to adjust water chemistry for taste and the 5.2 stabilizer has 25 grams of something I can't pronounce in it? How does that compare to the mineral levels? Would this alter the taste more that a few grams of salt will alter it?
 
Phosphates do indeed make good buffers if you follow the general rule for buffer formulation and that is to prepare buffers for stabilization at a pH within 1 pH unit of the pK of the acid/base pair being used. For the pair phosphoric acid/mononbasicphosphate the pK is 2.12 (at 20 °C). For the pair monobasic phosphate/dibasic phosphate it is 7.21 (the pH 7 technical buffer widely sold for pH meter calibration is a phosphate buffer). A buffer has maximum buffering capcacity at the pK of it's acid base pair and reduced buffering capcacity the farther away you get. Your clue that something was wrong here is the high ratio of monobasic to dibasic salt you calculated. If you are familiar enough with this subject that you can design a buffer yourself (i.e. without reliance on an online calculator) you will also be able to calculate the buffering capacity of a phosphate buffer at pH 5.2 and compare it to the buffering capacity of water with a given alkalinity and/or to the buffering capacity of malt (which is around 20 mEq/kg). You won't do much of this before you conclude that a phosphate buffer is completely unsuitable as a mash pH stabilizer and that's the case whether you formulate it yourself or buy it from someone else.

Interestingly enough the product you refer to is designed to buffer at about pH 6.0 in DI water. Apparently it relies on the malt itself to supply some of the monobasic phosphate. It still isn't at all effective at anywhere near the recommended dose and to exceed the recommended dose would load the beer with way too much sodium.

The commercial example wouldn't exist if the manufacturer didn't have ethical shortcomings.
 
I’ve often wondered how the same company that sells the wonderful StarSan could sell 5.2. As far as I know, everything else they sell works. Do you suppose the chemists are gone and the company is now being run by lawyers and accountants? (Sigh) I’ve sent them two emails recently that went unanswered. It could be worse, it might be (gasp) marketing.

I fear that 5.2 is worse than useless; they’re selling false hope. It would be easy for someone to ignore an actual pH problem in the belief that they were covered.

I’m with you AJ, I don’t like salty beer. Especially salty astringent beer.
 
Hmmm, interesting points. If we consider that 25g of sodium anything creates 1320ppm sodium (that is, 25,000mg/18.9271L), it is way over anything that occurs in most water sources. (Someone please check my math). However, I have not tasted any noticeable difference in the water, but I may not be a good taster. That's why I said it's probably not necessary. I understand that with today's well modified malts, this is not usually a problem, and had a brewing buddy do a pH test on his mash and it was within range without any pH adjustments. However, I have heard that commercial breweries treat their water with food grade phosphoric acid to lower the pH before doughing in.

In your all's opinion, does the mash even need a phytase rest to lower the pH? Or will the phytases be active enough at the higher saccharification temperatures to get the job done?
 
The Ph and buffering capability of the grain seems to drive the pH the most, and for me it seems it's never the same, and never matches the various calculators. I always dough in, then measure the pH then adjust with lactic acid. After experimenting with several mashes, the water calculators, and doing a little reading on pH I came up with this simple equation that works for me:

mL of lactic acid needed = change in pH * weight of grain in lbs

oh yeah, I never do an acid rest.
 
Hmmm, interesting points. If we consider that 25g of sodium anything creates 1320ppm sodium (that is, 25,000mg/18.9271L), it is way over anything that occurs in most water sources. (Someone please check my math).

You gotta make sure and only take out the sodium's mass if you add something like sodium phosphate or something else. It is the sodiums weight by itself that contributes to ppm sodium. You can figure that by taking a ratio of their masses within the whole molecule. So for Na2HPO4(dibasic) the ppm Na can be found by multiplying the weight you added times the ratio.

46(molar mass of 2 sodiums)/whatever the bottle says for molar mass (it is either anhydrous or probably the hydrate)
 
In your all's opinion, does the mash even need a phytase rest to lower the pH? Or will the phytases be active enough at the higher saccharification temperatures to get the job done?

It all depends on buffering capacity and stress on the buffers. There are multiple buffers. One of the major ones is from the inorganic phosphates in malt but there are lots of other buffering pairs as well. The buffering capacity of the water also comes into play. The calcium/phytin reaction is a player too but not a major player.

Even for DI/RO water (0 buffering capacity) most beers will need some acid. This can be in the form of acid from a bottle (lactic acid, phosphoric acid, CRS) or from acidulated malt or sauergut or from dark malts. You can make life simple for yourself by brewing with 0 (or very low) alkalinity water and using sauermalz. See the Primer in the stickies for how to do this. Of course this simplistic approach denies you the flexibility you might want in which case there are several spreadsheets and calculators you can use. But there is no 'silver bullet' that ties your pH to the desired value irrespective of what else you do.
 
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