Beta Glucan Rest and Target pH

[jabraben]

I'm planning to brew a robust porter as the first batch with some locally grown and malted barley that the maltster informs me is high in beta glucans. I'm planning a 20 minute beta glucan rest at 113F then a 60 minute sacc rest at 152F. For this beer I'd normally build my water to target a mash pH of around 5.4 but I'm trying to figure out how address the fact that optimal beta glucan rest pH is around 4.5 - 5.0 pH. I understand the factors affecting pH in a typical single infusion mash but I cannot get my head around this situation. I use Brun Water and I'm thinking maybe I should start by working up what it would look like using my typical water profile for a single infusion mash, then back the mash water down to the amount that will go in for the beta glucan rest infusion and see if that puts me in the ballpark of an appropriate pH for the step. The problem I see with this is that I know a mash step doesn't reach its pH immediately and I imagine Brun Water assumes a mash that's had time to reach equilibrium. I'm stumped. Can anybody advise me?

 

[Silver_Is_Money]

The pH ranges in which the various enzymes of import to brewing function are generally rather broad, and if your literature is reliable it is probably indicating peak enzyme efficiency at nominal mash temperature, since in my readings of many older peer reviewed brewing documents over the years that appears to be the standard method for the reporting of enzyme peak pH activity. On top of that the pH near enzyme peak at mash temperature may well be closer to 5.4 pH when corrected to room temperature to begin with. RDWHAHB

 

[Silver_Is_Money]

Beta Glucan is often associated with greater viscosity, which can debatably be perceived as an increase in mouthfeel. Getting rid of it may be highly desirable for the likes of a crisp lager, but you may find a heavier mouthfeel quite appropriate in a Porter. If the malts Kolbach Index (also called SNR) is 35 or greater there is likely little to no need for step mashing. If it is below 35, then step mashing is appropriate.

It wouldn't happen to be 'West Branch Malt', would it? Their lowest SNR malt is their Vienna, at a nominal 40.7. I'm tossing this out because if the Mt. Vernon you list is the one that is in Ohio, then your mentioned local malt may be West Branch.

 

[DuncB]

I found this article helpful.
http://braukaiser.com/wiki/index.php/How_pH_affects_brewing

 

[jabraben]

Beta Glucan is often associated with greater viscosity, which can debatably be perceived as an increase in mouthfeel. Getting rid of it may be highly desirable for the likes of a crisp lager, but you may find a heavier mouthfeel quite appropriate in a Porter. If the malts Kolbach Index (also called SNR) is 35 or greater there is likely little to no need for step mashing. If it is below 35, then step mashing is appropriate.

It wouldn't happen to be 'West Branch Malt', would it? Their lowest SNR malt is their Vienna, at a nominal 40.7. I'm tossing this out because if the Mt. Vernon you list is the one that is in Ohio, then your mentioned local malt may be West Branch.

We grew the barley at the farm associated with the college where I work, Kenyon College, so any fault in the grain is all ours. We unfortunately didn't have it run through the full range of testing before malting so whatever led to the high beta glucans wasn't detected until too late for the maltster to do anything about it. I forget the unit of measurement that he cited for the beta glucans but I can say it was in the hundreds and our number was more than double the typical range so the beta glucan rest is necessary if I don't want a lump the shape of my mash tun.

 

[Silver_Is_Money]

Flaked or Rolled Oats are very high in beta glucan, and they are common additions to certain varieties of Stouts. Stouts are in the Porter family, and a robust Porter is what at one time (back in the age when Porters were at their peak) was factually classified as a 'Stout Porter'. (Stout and Robust being synonyms)

I think you will be fine at a nominal room temperature mash pH of 5.4. If measured at your full (or main) mash temperature your pH will measure at about 0.22 points lower than 5.4.

You will effectively be producing an Oatmeal Stout without the need to bother with adding oatmeal. If you are concerned about poor filtration properties leading to a stuck mash that won't run off, then toss in a couple 'robust' handfuls of rice hulls.

 

[hopjuice_71]

The pH ranges in which the various enzymes of import to brewing function are generally rather broad, and if your literature is reliable it is probably indicating peak enzyme efficiency at nominal mash temperature, since in my readings of many older peer reviewed brewing documents over the years that appears to be the standard method for the reporting of enzyme peak pH activity. On top of that the pH near enzyme peak at mash temperature may well be closer to 5.4 pH when corrected to room temperature to begin with. RDWHAHB

This is sage advice.

 

[DuncB]

You could add glucanase enzyme
β-glucanase enzyme is used to break down the beta glucans in the cell walls of grains. These beta glucans cause gumminess in the grain, similar to bread dough, and can lead to problems with excess haze and stuck/slow lautering. This is especially true for mashes containing significant wheat or rye, as these grains do not have a husk like barley and tend to drain poorly and gum up. Glucanase enzyme can reduce or eliminate the need for bulky additions like oat hulls to circumvent this problem. It is also highly beneficial if brewing with unmalted adjuncts, which can have a similar problem.

glucanase can be added directly to the mash to work alongside the saccharification stage. Typical addition rates are 0.5 – 1 litre per tonne of grist, which equates to roughly 2.5 – 5 mL for a standard 23 litre batch of beer. The enzyme is highly active from 40°C to 75°C (optimum 60°C) and from pH 3.5 to 6.5 (optimum 5.5), which is well within normal mash ranges. It is deactivated during the boil.

 

[Silver_Is_Money]

Who wants a thin and crisp tasting robust Porter? Personally that wouldn't be my cup of tea. And if the recipe is planned to be robust (meaning stout) as claimed, and is likely thereby in the ballpark of 40+ SRM, it's doubtful if a bit of haze is going to spoil the party. Plus he's already attempting to mitigate the concern via an appropriate rest...

 

[cire]

Who wants a thin and crisp tasting robust Porter? Personally that wouldn't be my cup of tea. And if the recipe is planned to be robust (meaning stout) as claimed, and is likely thereby in the ballpark of 40+ SRM, it's doubtful if a bit of haze is going to spoil the party. Plus he's already attempting to mitigate the concern via an appropriate rest...

Yes.

In a brief search I found no information for beta glucan dating much before the middle of the last century. That was about the time Pilsner popularity spread around the world and Porter was virtually forgotten. From this paper it might be thought Guinness were more concerned about beta gluten's influence on the mash process.

 

[Silver_Is_Money]

20 minutes at 113 degrees F. (45 C.) will degrade much of the Beta Glucan due to the activation of the β-glucanase enzyme. @jabraben is on the right track with this. Where (in my opinion) he is off track is in perceiving a critical need to mash at pH 4.5 to 5.0 whereby to "peak" stimulate the activity of the β-glucanase enzyme. I just read a dissertation on the brewing of 100% oat malt beer, for which there was no mention of any effort made to adjust mash pH, and for which test mashes were undertaken at between 5.78 and 5.82 pH. The resulting beer was perfectly acceptable as to flavor and stability, despite the pH being well above the "peak" pH for β-glucanase. The 20 minute hold at 45 degrees C. was the primary key to stimulating sufficient β-glucanase activity. pH for the case of this enzyme must be well less important.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/j.2050-0416.2011.tb00487.x

 

[jabraben]

20 minutes at 113 degrees F. (45 C.) will degrade much of the Beta Glucan due to the activation of the β-glucanase enzyme. @jabraben is on the right track with this. Where (in my opinion) he is off track is in perceiving a critical need to mash at pH 4.5 to 5.0 whereby to "peak" stimulate the activity of the β-glucanase enzyme. I just read a dissertation on the brewing of 100% oat malt beer, for which there was no mention of any effort made to adjust mash pH, and for which test mashes were undertaken at between 5.78 and 5.82 pH. The resulting beer was perfectly acceptable as to flavor and stability, despite the pH being well above the "peak" pH for β-glucanase. The 20 minute hold at 45 degrees C. was the primary key to stimulating sufficient β-glucanase activity. pH for the case of this enzyme must be well less important.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/j.2050-0416.2011.tb00487.x

You misunderstand me. I'm not saying it has to be in that pH range. I'm asking whether I should do anything to accomodate that optimal range. I'm currently thinking I won't make any adjustments because enzymes will work over a greater pH range than what is strictly optimal, albeit at a reduced effectiveness.

 

[Silver_Is_Money]

You misunderstand me. I'm not saying it has to be in that pH range. I'm asking whether I should do anything to accomodate that optimal range. I'm currently thinking I won't make any adjustments because enzymes will work over a greater pH range than what is strictly optimal, albeit at a reduced effectiveness.

I'm glad that my misunderstanding has led you to truth.

 

[jabraben]

Thanks for the back and forth. It helps to talk some things out to refine one's understanding of a thing.

 

[Silver_Is_Money]

Don't forget the rice hulls. I don't know your intended grist weight or water volume or OG, but if beta glucan is as high as you say it is, perhaps 1/2 Lb. per 10 Lbs. of grist might be prudent.