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hector · 05-14-2012, 09:04 AM

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

scinerd3000 · 05-14-2012, 10:56 AM

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.

**ajdelange** · 05-14-2012, 12:52 PM

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).

**pjj2ba** · 05-14-2012, 03:37 PM

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

Liquisky · 05-24-2012, 04:14 AM

(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?

ClaudiusB · 05-24-2012, 04:42 AM

Quote:

Originally Posted by ajdelange

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

Cheers,
ClaudiusB

hector · 05-24-2012, 10:16 AM

Quote:

Originally Posted by ClaudiusB

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

No !

I do it every time , too .

Hector

sfrisby · 05-24-2012, 10:54 AM

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 %.

**pjj2ba** · 05-24-2012, 02:13 PM

Quote:

Originally Posted by Liquisky

(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?

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

hector · 05-24-2012, 08:45 PM

Quote:

Originally Posted by sfrisby

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

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