Is the protein rest useless ?!

Hi there !

As far as I know , the gelatinization temperature of malted Barley is 140-150 F .

The pale malt I use is moderately modified , therefore I always do the protein rest at 125-130 F and then raise the mash temperature to 150 F .

I'd like to know if the protein rest is totally useless , as the malt hasn't reached the gelatinization temperature yet .

Hector

Proteins and gelatinization have to do with different things. gelatinization refers to starch granules swelling and becoming soluble and the protein rest causes changes which influence the breakdown of proteins into short, medium and long chains. Free amino nitrogen is influenced by protein rest duration as are the head retention proteins and the proteins dealing with the body.

For homebrewing purposes it isn't as important as it would be for an industrial brewery. If you are trying to emulate a specific style then it is one thing, however normal malt generally doesn't need a protein rest. If too many proteins are broken down, you could end up with very poor head retention and body also.

That being said, depending on the malt analysis, some malts could benefit from a protein rest. An example would be a low WK index which could lead to a lesser level of FAN for yeast health and would need a protein rest to correct. If you did a protein rest on a malt with a high WK index, it could be detrimental for the resulting beer.

A pro brewer with a PhD in biochemistry gave us a lecture on the biochemistry of mashing in which he showed one slide divided into 3 fields. One depicted a jolly looking fat man in a red suite with a long white beard. The second showed a cute little rabbit with a basket full of brightly colored eggs and the third had only text: "value of a protein rest". That pretty clearly conveyed his opinion. However on the 2 occasions where I omitted the protein rest in a mash using Maris Otter malt the resultant beers had protein hazes that persisted for the life of the beer (over a year). That shaped my opinion. Though I am sure it is not absolutely necessary with today's well modified malts I do one in every beer without detriment (thus far). The usual fear is that head retention will be effected and if you over do it that might well turn out to be the case. Guess I haven't over done it (yet).

I certainly wouldn't consider a protein rest to be fictitious/not needed. No maltster makes perfectly malted barely that is converted exactly the correct amount to work optimally for every brewer's system. It is a compromise so it will work well with most brewery systems. That is, work well, but not optimally. The only way to to that is to make the malt yourself to match your processs - like they do at Pilsner Urquell. When I recently asked one of their brewers if he would recommend a protein rest for commercial (pilsner) malts. He said absolutely.

I recently decided a good analogy is that altering saccharification temperatures is like messing with the bass adjustment knob on a stereo and conducting a protein rest is like messing with the treble adjustment knob. Yes you can change the quality by just messing with the bass knob, but you can do a lot more if you mess with BOTH knobs. Homebrewers seem to not want to/are afraid to, mess with the treble knob (protein rest).

Perhaps I'll look around for a paper where someone has characterized the protein size fractions at various times/temps during the mash. I assume the big boys shoot for target protein size fraction ratios

(quote) Perhaps I'll look around for a paper where someone has characterized the protein size fractions at various times/temps during the mash. I assume the big boys shoot for target protein size fraction ratios (quote)

Any luck in your research?

ajdelange said:

Though I am sure it is not absolutely necessary with today's well modified malts I do one in every beer without detriment (thus far). The usual fear is that head retention will be effected and if you over do it that might well turn out to be the case. Guess I haven't over done it (yet).

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I thought I was the only homebrewer left doing a protein rest.



Cheers,
ClaudiusB

ClaudiusB said:

I thought I was the only homebrewer left doing a protein rest.

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No !

I do it every time , too .

Hector

I thought it was only important for grain bills with high wheat content. I always do one when brewing a wheat beer. However, others brews where there is maybe 1lb of wheat in a 10lb bill I don't. What I'm taking away is it is beneficial to do regardless of the wheat %.

Liquisky said:

(quote) Perhaps I'll look around for a paper where someone has characterized the protein size fractions at various times/temps during the mash. I assume the big boys shoot for target protein size fraction ratios (quote)

Any luck in your research?

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Haven't had the chance yet. Perhaps next week.

sfrisby said:

I thought it was only important for grain bills with high wheat content. I always do one when brewing a wheat beer.

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John Palmer says in his "How To Brew" :

This rest should only be used when using moderately-modified malts, or when using fully modified malts with a large

proportion (>25%) of unmalted grain, e.g. flaked barley, wheat, rye, or oatmeal.

I always do this rest because the pale malt I use is moderately modified .

Hector

hector said:

I always do this rest because the pale malt I use is moderately modified .

Hector

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Hmmmm. Ok. So how do we know if our grain is only moderatly modified?

sfrisby said:

So how do we know if our grain is only moderatly modified?

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The best way is asking the malt producer about it .

I take a randomly amount of the pale malt and look at each seed carefully to see the length of the Acrospire underneath the husk .

Hector

This is an interesting question because there a some people that believe that the amount of protein breakdown that can happen in a protein rest is next to none. The reason being is that the enzymes are very heat sensitive and are denatured during kilning. The people who think this believe that the rest is important for the breakdown of beta glucan (the cell wall material that surrounds the starch). This beta glucan is very viscous if it is not broken down and this rest helps with breaking down these materials. This is why John Palmer says to do it if you are using roasted barley because that is unmodified barley and has all of that beta glucan present.

That being said, what I just stated about protein breakdown isn't a proven fact and is not accepted by everyone (most German brewers believe that there is protein breakdown at this stage, as well as Dan Gordon of Gordon Beirsch- who studied in Germany), but you will break down some beta glucan which will decrease the wort viscosity(making lautering easier). However it is under debate whether or not there is a breakdown of protein as well.

hector said:

The best way is asking the malt producer about it .

I take a randomly amount of the pale malt and look at each seed carefully to see the length of the Acrospire underneath the husk .

Hector

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The acrospire length is a measure of modification and a well modified malt should have 75-80% of the malt have acrospires that have grown to 75-100% of the length of the grain.

I do a rest at 104°F for ß-glucan. The proteases operate between 122 and 128 °F (according to Noonan).

The mash temp and pH effects are pretty complex and interrelated.
The table below (from "Malting and Brewing Science" Briggs, Hough et.al)
shows that the greatest amount of phosphate buffers are also
produced at the protein rest, (because it the best temperature
for phytase activity), this in turn effects the pH. The
amount of protein broken down to permanently soluble protein
is important because that is what the yeast eat, and because
it won't be precipitated with tannins (meaning clearer beer).
The pH will affect both the amount of harsh-tasting tannins
extracted from the husk but also the amount of precipitation
(haze) that is produced (because of precipitation with the
proteins). pH also affects exract, as the greatest
extract occurs between pH 5.3 and 5.9.

Highest extract 149-155
Highest yield of fermentable extract 149
Highest yield of permanently soluble nitrogen 122-131
Highest yield of acid buffers 122-131

So the protein rest has many effects, whether it will have
more effect on a homebrew than say, fermenting at an
improper temperature, or not oxygenating, will vary from
yeast to yeast and recipe to recipe and process to process.
A protein rest in general seems like a good idea though.

Ray

ajdelange said:

A pro brewer with a PhD in biochemistry gave us a lecture on the biochemistry of mashing in which he showed one slide divided into 3 fields. One depicted a jolly looking fat man in a red suite with a long white beard. The second showed a cute little rabbit with a basket full of brightly colored eggs and the third had only text: "value of a protein rest". That pretty clearly conveyed his opinion. However on the 2 occasions where I omitted the protein rest in a mash using Maris Otter malt the resultant beers had protein hazes that persisted for the life of the beer (over a year). That shaped my opinion. Though I am sure it is not absolutely necessary with today's well modified malts I do one in every beer without detriment (thus far). The usual fear is that head retention will be effected and if you over do it that might well turn out to be the case. Guess I haven't over done it (yet).

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I'm a beginner here. How do you know that you had protein haze and not starch haze, if it even matters. Have you ever tried using egg shells to clear the beer? Thanks.

When I have done a protein rest 3 or 4 times, it resulted in some of the clearest beer with thinnest head. Since the protein rest obviously does something, then it might not be useless. I have not done a protein rest in several years, but in future, if I want a very clear beer and I don't care about head retention, like maybe in an American pilsner or something like that, it could find a use in my brewery. It is a tool in the toolbox.

I have been curious what the impact would be on an NEIPA. Those are a style that will often have a large amount of flaked wheat and oats. Clearly the goal with this style is not clarity, but I have wondered if if a protein rest would be a positive or negative for the style.

I used to do a protein rest for all my beers when I first started out...cuz Dave Miller said I should. I stopped at some point. I have a few other beers that I brew with 10% to 20% oats/wheat/rye, though I have mostly moved to using malted wheat and rye (for no real specific reason...though it gives me some confidence when using low DP English base malts...and Scott Janish hinted at some negatives of flaked adjuncts in hazies). One of these days I will probably pick up a recirculating all-in-one system and play around with different rests.

CascadesBrewer said:

I have been curious what the impact would be on an NEIPA. Those are a style that will often have a large amount of flaked wheat and oats. Clearly the goal with this style is not clarity, but I have wondered if if a protein rest would be a positive or negative for the style.

I used to do a protein rest for all my beers when I first started out...cuz Dave Miller said I should. I stopped at some point. I have a few other beers that I brew with 10% to 20% oats/wheat/rye, though I have mostly moved to using malted wheat and rye (for no real specific reason...though it gives me some confidence when using low DP English base malts...and Scott Janish hinted at some negatives of flaked adjuncts in hazies). One of these days I will probably pick up a recirculating all-in-one system and play around with different rests.

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dmtaylor said:

When I have done a protein rest 3 or 4 times, it resulted in some of the clearest beer with thinnest head. Since the protein rest obviously does something, then it might not be useless. I have not done a protein rest in several years, but in future, if I want a very clear beer and I don't care about head retention, like maybe in an American pilsner or something like that, it could find a use in my brewery. It is a tool in the toolbox.

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Similar situation.

I used to do a stepped mash that would dough-in @ 95F, rest @ 131F for :15mins, Beta @ 145F, Alpha @ 158F, mash out @ 172F. Beers were clear which I prefer, but body was lacking.

Lately I mash in 140F, Beta@145F, Alpha@161F, mash out @ 169F. No protein rest. Beers have more body, better lace, but less clarity. My beer intake has slowed since Christmas (multiple reasons) so the two kegs on tap have had some long sits 'aging'. They have finally cleared quite nicely after nearly 3 months.

I read "somewhere" about "something" happening during mash-out at a very specific temperature of 170-171F. Cooler than 169 or warmer than 172, not happenin'. Don't remember what it was or where I read it, but it did involve protein and did involve clarity and improved body. Can someone help shake the cobwebs in my brain? I'm trying to find the Holy Grail of Hoch-Kurz step mashes to reduce haze, maximize extraction and efficiency, maintain body and mouth feel, but prevent chill haze. Even if it requires a protein rest with highly modified grains.

Gracias'

This question runs parallel to another question, which I asked the forum some time ago, which is: are there still nowadays in commerce malts which are undermodified and need a protein rest according to all sacred books?

The conclusions that I draw from the thread below is that a rest at 54-57 °C (not the classical protein rest at 50°C or lower, but strictly at around 55°C) is beneficial when using "moderately modified" malts, which have a Kolbach index of 35 or 36, or some other characteristics which will be read in the thread. Those malts still exist in normal commerce and are not rarities. They are not "undermodified" malts but what many would describe as "moderately modified". Not doing such a rest would not result in problems, but doing it will possibly result in a better beer and will make sense. This pause should be always avoided when using typical British or American base malts, as it would be detrimental.

The thread is here: The strange case of the disappeared under-modified malt

Brooothru said:

I read "somewhere" about "something" happening during mash-out at a very specific temperature of 170-171F. Cooler than 169 or warmer than 172, not happenin'.

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For a long time after moving to BAIB I would still do a mash out (though without any idea of a magic 170-171 range). I have read enough about some positive impacts on mash out (head retention, boost in efficiency...maybe a boost in dextrins which might not be a good thing). A mashout is easier on my 5 gal setup with a hoist, but a pain for my stovetop 2.5 gal batches so I stopped doing them there. I cannot say I notice a difference between my beers with or without a mashout. hmmm

Is there any connection between Diastatic Power and Modification? I always thought there was and that low diastatic power was a sign of low modification, but I now think diastatic power is more a function of the barley variety and malting process, right? There was talk earlier about inspecting barley to tell the level of modification that I did not understand. Is there info on a malt spec sheet that indicates the level of modification?

Edit: Looks like the "the disappeared under-modified malt" thread answers some of my questions.

I am not sure if it is directly related to Protein Rests and topics, but there is a 3 part series on the Master Brewers podcast titled "The Six-rowification of North American Two-row". (interview with Joseph Hertrich) It really made me think that there might be a completely different set of rules that apply to mashing with American 2-Row vs European 2-Row.

https://www.masterbrewerspodcast.com/088p1https://www.masterbrewerspodcast.com/088p2https://www.masterbrewerspodcast.com/089

CascadesBrewer said:

I have read enough about some positive impacts on mash out (head retention, boost in efficiency...maybe a boost in dextrins

Edit: Looks like the "the disappeared under-modified malt" thread answers some of my questions.

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That is getting very close to what I vaguely remember reading about head retention and dextrins during mash-out at a specific range 170-170F. What I don't recall is the impact a protein rest at lower mash temps would have (either positive or negative) on processes at mash out temperatures.

I'll check out the thread you cited to see if it sheds some light. Thanks.

CascadesBrewer said:

Is there any connection between Diastatic Power and Modification?

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Not really. At least not that I've ever seen.

CascadesBrewer said:

I always thought there was and that low diastatic power was a sign of low modification, but I now think diastatic power is more a function of the barley variety and malting process, right?

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Yes, the two big drivers are the variety of barley (or wheat, etc.) and the malting process, specifically the degree of kilning. Higher temps or longer kiln times denature more enzymes than lower/shorter.