ph and efficiency

[boydak]

I did a quick search and did not find an answer.
Since beginning all grain my efficiency has been about 55%. This weekend I used an additive that would make my mash water a 5.0 no matter what. My efficiency sky rocketed to a 74%.
I did a few other things a little diffently but was wondering if ph effects efficiency?

 

[VikeMan]

pH can affect efficiency, but not really significantly unless the pH is pretty far out of whack.

There is no product that will take mashes to pH 5.0 (or any other specific pH) no matter what. They are snake oil. An example is 5.2 Mash pH Stabilizer, which is basically useless.

 

[IslandLizard]

I did a few other things a little diffently

What things?
Chances are your efficiency improved due to those rather than a magical pH "Stabilizer." BTW, 5.0 is a bit too low.

75% efficiency is still not stellar, pretty much a minimum to strife for. Is that 75% Mash efficiency or Brewhouse efficiency?

 

[bracconiere]

Since beginning all grain my efficiency has been about 55%

my god! the only way i can imagine getting that low, would be using uncrushed malt, and sparging full bore!

 

[IslandLizard]

my god! the only way i can imagine getting that low, would be using uncrushed malt, and sparging full bore!

No, that would result in 0% efficiency. An OG of 1.000 after the mash.

 

[McKnuckle]

"The pH optima of alpha amylase is also higher at 5.3–5.7 compared to 5.1–5.3 for beta amylase."
Source: The Oxford Companion to Beer Definition of alpha amylase

75% efficiency is still not stellar, pretty much a minimum to strive for.

Geez, I wouldn't go that far. Consistency is more important. Chasing efficiency as a primary goal can be an exercise in frustration. 70% is still alright if you have a reliably repeatable process. But even that is an arbitrary cut-off for "acceptable."

 

[bracconiere]

No, that would result in 0% efficiency. An OG of 1.000 after the mash.

1.000? is that temp corrected? i think you'd still get 40-50%!

 

[bracconiere]

Geez, I wouldn't go that far. Consistency is more important.

i dissagree, i hated it when i consistently got 63-65%. much happier now i get 92%! now i can brew with 15lb's base malt instead of 25!

 

[McKnuckle]

Well now, I didn't say 65% or lower, I said 70%. I'd prefer higher, but again, the point is to have a reliable process, not to show off a number.

And respectfully, I doubt you get 92% mash efficiency*. Most homebrewers don't rigorously follow the calculations: http://braukaiser.com/documents/efficiency_calculator.xls

...and again, that's still okay. because it's about consistency, not a specific number.


*Let's say I have 2 kg of grain and 13 L of water in my mash. Let's say that I achieve 100% conversion efficiency, which I will not, but it illustrates my point. I will still have 0.75 L/kg (0.09 gal/lb) absorbed by the grain and not recovered. So that's 1.5 L of wort not recovered. 11.5/13 = 88.5% mash efficiency. To get 92% you'd need to have 100% conversion and about 0.06 gal/lb absorption.

 

[bracconiere]

i could post my recipe, and OG and the fact i got two 5 gal kegs full. but that brings up the question of what @boydak 's recipe was?

 

[IslandLizard]

1.000? is that temp corrected?

Yes, with temp correction.

i think you'd still get 40-50%!

Not from unmilled malt...
Unless there's a boatload of malt dust clinging to it. In that scenario, 1.001 may be achievable.

 

[bracconiere]

Not from unmilled malt...
Unless there's a boatload of malt dust clinging to it. In that scenario, 1.001 may be achievable.

damn, now i want to try it.....

 

[IslandLizard]

damn, now i want to try it.....

No need to. I have seen proof. But it's not mine, and I'm not sure that member wants to volunteer that (slightly dark) episode of his homebrewing career. Although it's funny as hell, true HBT core, more than just a few of us would appreciate.

 

[Silver_Is_Money]

"The pH optima of alpha amylase is also higher at 5.3–5.7 compared to 5.1–5.3 for beta amylase."
Source: The Oxford Companion to Beer Definition of alpha amylase

Those pH's are at mash temperature. Add about 0.20 to 0.25 pH points for room temperature.

 

[Silver_Is_Money]

I've mashed at a measured 5.1 pH and hit my anticipated pre-boil gravity within my usual margin for error. And likewise at 5.7 pH. I don't really think that any reasonable mash pH can toss off efficiency much, if at all.

As for the others who have already pegged this, a phosphate based pH stabilizer (buffer) is not going to buffer a mash pH at 5.0 or 5.2.

Whatever caused your efficiency to improve, it was not likely to be mash pH.

 

[bracconiere]

And likewise at 5.7 pH

but that's over the dreaded tannin threshhold! of 5.6

 

[Silver_Is_Money]

but that's over the dreaded tannin threshhold! of 5.6

It turned out to be the very best Bohemian Pilsner I've ever made. Delicious.

Rochefort, arguably the best of the world famous Belgian Trappist Monastery breweries, admits to mashing intentionally at pH 5.8 to pH 5.9, as can be read in the book titled: "Brew Like A Monk".

 

[bracconiere]

Rochefort,

(take this as a humorus comment)

but isn't that one of the cheese's where the monk's rub it in their arm pits or something to get it moldy? lol, and i would say it is delicious! great on steak!

edit god's disciples B.O. now in cheese form!


but back on topic, would a higher ph cause a more significant chance of mold growth?

 

[Silver_Is_Money]

Rochefort adds a mineral based acid within the boil to adjust the Wort to pH 5.2. It's all in the book.

 

[boydak]

pH can affect efficiency, but not really significantly unless the pH is pretty far out of whack.

There is no product that will take mashes to pH 5.0 (or any other specific pH) no matter what. They are snake oil. An example is 5.2 Mash pH Stabilizer, which is basically useless.

5.2 is the stuff I used.

 

[boydak]

my god! the only way i can imagine getting that low, would be using uncrushed malt, and sparging full bore!

Thanks! that is helpful.

 

[Silver_Is_Money]

5.2 is the stuff I used.

As I understand it (subject to correction, with my personally unsubstantiated second hand knowledge admittedly coming only from the regurgitated hearsay of a multiplicity of others, and thus representing only at best circular reasoning, or circle jerking) this product was initially designed to meet the needs of a single and specific customer, and virtually no one else has found it to work in their application.

As an example which may (or may not?) find relevance here: Phosphoric Acid (representing phosphates and phosphate buffers) has its first two (of three) dissociation pKa's at 2.16 pH and 7.21 pH. Buffering is generally found to take place most efficaciously only within about +/- 1 pH points of a pKa. The range of pH's of interest within the mash are not within 1 pH of either of these two pKa's.

 

[Yooper]

5.2 is the stuff I used.

Do your own research on it. I've tried it. It didn't reduce my mash pH, and it left a strange taste in my beers. Then I learned about mash pH and water chemistry and found out why it can't work.

 

[IslandLizard]

Phosphoric Acid (representing phosphates and phosphate buffers) has its first two (of three) dissociation pKa's at 2.16 pH and 7.21 pH. Buffering is generally found to take place most efficaciously only within about +/- 1 pH points of a pKa. The range of pH's of interest within the mash are not within 1 pH of either of these two pKa's.

You got it right, that's the reason why 5.2 can't possibly live up to its promise. Fooey Five Stars!
IIRC, it was AJ who taught us that, possibly over 10 years ago.

On a side note, Phosphoric Acid's double dissociation pKas and the associated titration curve are a textbook example of introductory teachings in Analytical Chemistry. It shows that buffering capacity clearly around those 2 bends (plateaus), providing students with an excellent exercise and visual of what's happening in those areas that doesn't happen on the steeper trajectories.