5.2 mash stabilizer - why is it not recommended

[ArcLight]

Some of the knowledgeable members of home brew talk are highly skeptical of 5.2 mash stabilizer.
Why?

I just read some of a chemistry book, and given my limited knowledge of chemistry, the idea seems sound, at least to some degree. But I may not be fully understanding whats happening.

1 - I assume 5.2 mash stabilizer doesn't add off flavors , as that would clearly make it ill suited for brewing.

2 - It appears that if the pH is too low, the 5.2 mash stabilizer will buffer it to around 5.2. The excess Hydronium ions will be neutralized by the conjugate base of the 5.2 mash stabilizer. I assume this is rare in brewing, unless using lots of dark grains or acidic water.
Or am I misunderstanding?


3 - if the brew water has some hardness, and that buffers the pH and prevents it from dropping to the desired range, would the 5.2 mash stabilizer cause the pH to drop to 5.2?
Or is what happens is the Hydronium ions in the mash bond with the elements in water that are making it hard, and are neutralized. Then the 5.2 mash stabilizer doesn't unbond the Hydronium ions, and doesn't lower the pH.


If one mixed up some 5.2 mash stabilizer and added it to pure water (pH 7) would the pH drop to 5.2?


(I already searched a number of 5.2 stabilizer threads without finding a scientific explanation, as opposed to "it doesn't work").

I am not advocating 5.2 stabilizer.
I just want to understand the science involved.
Could an alternative 5.2 buffer be created?

 

[Gavin C]

This is taken from Bru'n Water and relays a converstaion in which the maker essentially admits that the product does not do what it purports to.

Taken from here

SPECIAL NOTE: Five Star 5.2 Stabilizer is indicated by its manufacturer to "lock in your mash and kettle water at a pH of 5.2 regardless of the starting pH of your water". Evidence by homebrewers indicates that this product does not produce a mash pH in the preferred room-temperature range of 5.3 to 5.5. That evidence shows this product does produce some pH moderation in waters with high Residual Alkalinity. However, the mash pH tends to center around 5.8 (room-temperature measurement). While 5.8 pH is acceptable, it is at the upper end of the desirable mashing range. The evidence also shows that in waters with low Residual Alkalinity, this product shows little effect on mash pH. Since Five Star 5.2 Stabilizer is a compound with high sodium content, its use will elevate the sodium concentration in the brewing water. High sodium content can be undesirable from a taste standpoint in beer. Proper alkalinity control of mashing and sparging water may produce more acceptable brewing results for most brewers than with the use of 5.2 Stabilizer. To add emphasis to difficulty in using this product, the following conversation posted on Homebrew Talk between noted brewing water expert, AJ DeLange and the chemist from Five Star Chemical regarding their 5.2 Stabilizer product. "Tipped a few last night with the chemist who designed this product and was able to confirm that it is indeed a mix of phosphates (mono and di basic) that accounts for the presence of the malt phosphate. This is something I have long suspected and am pleased to have finally confirmed. Good manners prevented me from pressing him on it's efficacy and suitability relative to the statement on the label. But his comments on it were basically that most brewers shouldn't use it/need it and that it was put together for a particular brewery that had variable source water and no desire to make any effort to track that variability."


Off-taste: Perhaps. Too much sodium
Effective buffer: Not in the range we want as brewers

Conclusion: A totally ineffective product which cannot and does not do what it claims to. Total junk.

 

[hunter_le five]

There are a lot of good threads on this topic that can go into more detail than I can (specifically the commentary and research done by user ajdelange), but essentially the consensus is that it just doesn't work.

Maybe if you had a very specific water profile (presumably the one used by the brewery for which the product was originally designed) then it might actually work, but chances are you don't, and adding it to your mash will do more harm that good.

There is no magic powder that will take your mash from any baseline starting point and bring it right to 5.2PH. That's just not how that works.

If one mixed up some 5.2 mash stabilizer and added it to pure water (pH 7) would the pH drop to 5.2?

I'm not sure, but it's kind of irrelevant. You want your MASH to be at ~5.2, not the WATER.

 

[ArcLight]

There is no magic powder that will take your mash from any baseline starting point and bring it right to 5.2PH. That's just not how that works.

Is that really true?
Couldn't one find a weak acid & conjugate base and formulate a 5.2 pH buffer?
Something that won't affect the taste.
Would a low dose of Acetic Acid/Acetate ion work? If taste is an issue then use a weaker concentration that provides less buffering, and wont work with very hard water.

It would have a pH of 5.2, and provide a buffer in a +/-1 pH band.

 

[Gavin C]

Adding an acid will lower the pH. No doubt about it.

Lactic acid and acidulated malt are commonly used for mash pH adjustment. The water's pH is not of concern for the most part.

These acids will not behave as a buffer though. I can't see how acetic acid will behave differently. How will it act as a buffer resisting a pH change from a targeted range?

Edit: Why would a range of pH4.2-6.2 be of benefit

 

[JonM]

Varying grain bills contribute different amounts of acidity to the mash. A stout grain bill will create a more acidic mash than one using all pilsner. There's no one-size-fits all thing that will make a proper mash pH.

And 5.2 is too low for list beers anyway.

 

[ArcLight]

These acids will not behave as a buffer though. I can't see how acetic acid will behave differently. How will it act as a buffer resisting a pH change from a targeted range?

To create a buffer one makes a solution of a weak acid and it's conjugate base. That's not the same as just pouring in acid. You can vary the ratios to end up with a pH other than the acids pH. I used Acetic acid off the top of my head because it's somewhere near 5.2 (it's lower)


I'm not advocating on behalf of 5.2 stabilizer, or buffers in general.
I'm asking why they wont work.

 

[masonsjax]

The taste of acetic acid is offensive in most styles at a very low threshold. Lactic is more tolerable, and phosphoric has a pretty low flavor contribution.

It would be cool to be able to mix up a one size fits all magic pixie dust, but if that were possible, the water primer would be in the recipe section.

 

[Braufessor]

It will "work" under a very specific set of circumstances. However, it is sold as a "quick fix" for all circumstances. It does not "work" for the same reason I can't use the exact same water additions in B'run water for every beer style, and with 100% RO water all the way up to my 100% tap water (bicarbonate 270). You can't add one thing to 100's of different water/grain profiles and think you are going to get the same result.
Software like B'run water or others accounts for the amount and types of grains and their contributions as well as what you are starting with. 5.2 just says "throw this in" and "magic."

When you are describing - "couldn't you just add some acids and base and have it work" - yes. It is called a water spreadsheet. The acids and bases that you can use to achieve this and not add off flavors are things like lactic, phosphoric, gypsum, CaCl.....etc. How much and what types I need are not the same as what you might need. And, what I need in my stouts is not the same as what I need in my pilsner. 5.2 tends to suggest that those differences do not exist.

I am not sure if it was Martin or Aj (I think it was one of them) that said it best - 5.2 has the unique ability of only working for people who do not have pH meters.

 

[ArcLight]

The taste of acetic acid is offensive in most styles at a very low threshold. Lactic is more tolerable, and phosphoric has a pretty low flavor contribution.

It would be cool to be able to mix up a one size fits all magic pixie dust, but if that were possible, the water primer would be in the recipe section.

As I stated above, I threw out Acetic acid as an example because it's closer in pH to 5.2. It was just an example. It's might not be noticeable if one made a weak buffer. What about a different acid.

I am asking "Why is the idea of a 5.2 stabilizer unsound".

I'm not defending the 5 star product, or suggesting any specific weak acid & conjugate base as a buffer.

I want to understand scientifically why this wont work.

If you add a buffer to pure water, it will lower the pH, yes?
Then can something be formulated to work for brewing?

 

[bbohanon]

Honestly I have not found working up my own water profile with the proper brewing salts for mash and sparge water to be tedious or something I need an easy button like this solution for.
I like having the ability to "tweak" my profile to match the style of beer I am making. Its not all about just getting the water to a 5.2Ph (which may not work for alot of beers) in my mind..its everything in the water makeup that makes the beer all it can be (Calcium, Mag, Sodium, Sulfates, Cl/Sulf Ratio, Alkalinity, etc.).
Just me though...Being able to work up a complete water profile is critical if you ever want to get that specialized craft beer you love cloned properly. Craft breweries spend alot of time with their water to get their beers dialed in..you should as well.

 

[JonM]

I can't find it right now, but AJ wrote up a great post explaining the hows and whys of of how this stuff cannot work the way it is supposed to. I think it was from Feb. 2014 and has been repeated and cut and pasted. Search around and I bet you can find it.

 

[Gavin C]

@bbohanon

I agree. I enjoy the process too.

Since exploring water chemistry I have wondered why a buffer would even be a desirable thing to add to a mash. It is so easy to tweak and target a specific mash pH for any a given mash profile.

I guess asking why the product doesn't work would be eaily answered with.
Short answer:
It is the wrong chemical for the job it is advertized to do.

Long answer:
Sodium phosphates are not at all useful as a buffer in the desirable mash pH range. They are a weak buffer at pH ranges outside of what is desired.

A better question would be under what circumstances could pH5.2 do what it states. "Lock in your pH". Why should it work? It's claims are so lofty as to render the whole area of water chemistry obselete.

Better to try to prove the theoretical claims of the product. Ask "How can it work?" In exploring this question the answer to the OP's opposite question will reveal itself.

 

[Braufessor]

Water chemistry is complex - not so complex that it cannot be easily manipulated. But complex in the fact that there are many variables at play.

Anything you do in manipulating water chemistry for brewing depends on:
*starting water profile
*Ingredients (grain bill)
*Beer style and the flavor impact of specific ions on particular types of beers (and their corresponding ingredients).

Therefore - one solution will never work for every combination of variables.

Also, a couple assumptions seem to be starting points for this conversation:
1.) Achieving pH of 5.2 is all that matters and it is the goal all the time - it is not. Simply getting to a pH of 5.2 is not the "goal" of water chemistry in brewing.
2.) There is not an impact on flavor from what is being added...... there is - no mater what it is you are using. Adding more of anything will increase the odds of it impacting flavor. Adding a lot of something could be good in one set of circumstances and the same amount could be bad in another set of circumstances.

Asking "why 5.2 (or any other product) can't work under 100% of all circumstances is sort of like asking why we can't just have one pill that cures all illnesses.......uhhhhh..... because that is not the way it works. Unique problems require unique solutions.

 

[ajdelange]

It has been explained here a number of times but may be hard to find. In a nutshell, the titration curve of an acid, as base is added, plotted with pH on the horizontal axis and the amount of base added on the vertical axis (with increased base going downward as base has negative charge associated with it) looks like a staircase with the risers not quite vertical but in essence the treads are nearly flat and the risers pretty near vertical. In a tread a small increase in the amount of added base results in a large change in pH (because dBase/dpH is small) whereas in a riser it takes a lot of base to effect even a small change in pH because (dBase/dpH is large). If you have the Water book handy you will find the titration curves for carbonic acid and phosphoric acid there.

Now each acid has, associated with each proton it can release (3 for phosphoric, 2 for carbonic...) a number called the pK which is the pH at which half of the acid molecules have released the proton in question. The pK's are found in the center of the risers (at the inflection point). This is where the riser is steepest and a buffer has its greatest ability to work. Half way between risers where pH = (pK1 + pK2)/2 is where you have the least buffering capacity - the buffer doesn't buffer very well at all. For phosphoric acid the two relevant pKs (first and second protons) are 2.12 and 7.21). Thus the worst buffering occurs at pH = 9.33/2 = 4.66 which is disappointingly close to the region in which we want our mash pH to be. As a rule of thumb one does not prepare buffers for pH values more than 1 unit from a pK associated with the acid system to be used. Based on this we come to the conclusion that the phosphoric acid system is not a good choice for buffering brewing mash.

Another aspect of this is that 5.2 is a buffer composed of phosphate salts. If one relies on it to produce the protons that are needed to bring a typical pale beer mash to pH 5.4 or thereabouts it is going to take quite a bit to do that job. It takes about 10 mEq of protons to move 1 kg of pilsner malt to pH 5.4 and it takes a lot of sodium diphosphate to provide that much. It is, conversely, a very good idea to use phosphoric acid to get those protons and not nearly so much is required.

The use of salts of other acids with more appealing pK's is tempting but it is, again, much more efficient to use the acid itself.

 

[normonster]

Once you buy the stuff though, you have to use it.

 

[GotPushrods]

Once you buy the stuff though, you have to use it.

Your brewing notes will never blow away on a windy day again. So there's something!

 

[Gavin C]

Although not related to the product in question. I think this graph illustrates what @AJdelange was describing.

If the steep (riser) part of the graph is not at the desired pH the chemical in question is not a suitable buffer at that point. I guess for the magic pixie dust in question it's point of equivalence on a similar graph would be at about pH 5.8

Hope I'm not too off base.

 

[masonsjax]

I'm with bbohanon here. I'm primarily concerned with how my beers taste, with pH being a part of the equation. When I calculate my mineral and acid additions using brunwater, I first get the flavor ions where I want, then add whatever is needed to hit the correct pH range if it's not already there. Sometimes depending on the recipe, this can be a balancing act where I need to go back and tweak amounts of some additions or swap portions for something else. All in all it is an enjoyable part of the homebrewing process.

Plus what AJ said

 

[doug293cz]

Once you buy the stuff though, you have to use it.

No you don't, and I didn't (except maybe once before I knew better.)

Brew on

 

[ajdelange]

Although not related to the product in question. I think this graph illustrates what @AJdelange was describing.

It is related to the product in question because the product in question is composed of salts of phosphoric acid. The picture differs from the one I described in that the amount of base is on the vertical axis and the pH on the horizontal axis whereas in this picture they are reversed. Rotate this picture 90 ° and you have the same plot.

 

[ajdelange]

Once you buy the stuff though, you have to use it.

We did figure out a good use for it: fertilizer for plants with a high phosphate requirement. Most of the phosphorous mined in the world winds up as fertilizer.

As 5.2 is mostly monosodium phosphate with molecular weight 120 and the molecular weight of phosphorous is 31 so it's about 15% phosphorous and thus equivalent to a 0 - 15 - 0 fertilizer.

 

[mabrungard]

By the way, the Five Star website says of the product: "will lock in your mash and kettle water at a pH of 5.2 regardless of the starting pH of your water". Since we know that this cannot be true based on the chemistry and is not true based on observations, I have to wonder about the Federal Trade Commission's Truth in Advertising rules. https://www.ftc.gov/news-events/media-resources/truth-advertising Someone should look into that.