Where Does the Protein Go? - Home Brew Forums

Register Now!
Home Brew Forums > Home Brewing Beer > Brew Science > Where Does the Protein Go?

Reply
 
Thread Tools
Old 09-30-2013, 07:20 PM   #1
JustWeiss3
Recipes 
 
Sep 2013
Posts: 6


So I've brewed 2X now using a kit, like alot of people have probably started out with. However recently I've become interested in brewing on a more custom level. Despite my research I'm not fully understanding something. I've been stumped what happens to the high protein content of barley during the brewing process. Obviously the germination process is stopped when the enzymes are produced but why is it that beer generally ends up with such a drastically lower protein content? I know Proteins must be present for head retention and the fermentation process doesn't seem to involve consuming the polypeptides but clearly I'm not seeing the full picture. I was hoping someone could explain what happens to the proteins originally stored in the grain and most importantly, if there was anyway to retain alot of that protein content in the final product?

 
Reply With Quote
Old 09-30-2013, 07:43 PM   #2
Bensiff
 
Bensiff's Avatar
Recipes 
 
Mar 2008
, Washington, the state
Posts: 4,893
Liked 384 Times on 303 Posts


All that hot break and cold break material...that is where the bulk of your proteins get tied up, you would not want to retain that in beer. A little going to the fermenter is good for yeast health; but, too much is associated with off flavors...some folks don't care enough and dump it into the fermenter, others, such as myself whirlpool and let it settle out and send a clear wort to the fermenter. Obviously what you see is not soluble so it gets tossed. I suppose you could dry it up some and eat it or turn it into animal feed...I'd venture a guess larger breweries do just that.

 
Reply With Quote
Old 09-30-2013, 08:11 PM   #3
JustWeiss3
Recipes 
 
Sep 2013
Posts: 6

hmm, thanks. So basically the amount of protein that's soluble is very low?

 
Reply With Quote
Old 10-01-2013, 10:27 PM   #4
biertourist
Recipes 
 
Oct 2012
Woodinville, WA
Posts: 861
Liked 124 Times on 93 Posts


Much of the protein that is in the grain itself is in the germ and the polycarp layer of the barley kernel. The germ obviously gets left behind in the mash/lauter tun in it's solid form so that doesn't make it into the wort. The Alerone layer contains 30% of the barley kernel's proteins and releases some of those as our amylase enzymes during malting (so some of the protein content is tied up in enzymes) but some of it gets left behind in the husk. -This is why higher enzymatic power malts have higher protein contents and vice versa; much of the protein content IS enzymes.

The alerone layer is also releasing proteases during the malting process which are breaking down high molecular weight proteins into medium weight proteins (the ones that aid head formation / retention) and then further break down those medium weight proteins into amino acids and free amino nitrogen which is our natural yeast nutrient.

Well modified malts like pale ale malts and munich malt have these proteins broken down further and more of the proteases denatured than less modified lager malts which have more and higher weight proteins but also more enzymatic power / proteases available (see why a protein rest is recommended on these?).

As Bensiff stated the nonsoluable proteins come out of solution / form complexes via hot and cold break (and they're even less soluable at lower ph) so they get left behind.


I'm not sure why you think that more protein is a good thing; high protein levels are certainly responsible for chill haze and general product instability. The high molecular weight proteins are the ones that combine with polyphenols to form chill haze, the medium weight proteins are the head forming proteins and the little amino acids are our yeast nutrients.

Even very well modified malts have plenty of protein in the form of enzymatic power, have enough protein to provide a good head, and provide enough amino acids for yeast nutrition so focusing on increasing finished protein levels will probably decrease your beer quality over all; not increase it.



Adam

pharaohpierre Likes This 
Reply With Quote
Old 10-01-2013, 10:58 PM   #5
smccarter
Registered User
Recipes 
 
Feb 2013
Milton, Florida
Posts: 1,034
Liked 173 Times on 124 Posts


Quote:
Originally Posted by Bensiff View Post
... (I) whirlpool and let it settle out and send a clear wort to the fermenter...
How do you whirlpool? What is the technique?

With the wort chiller and the braided tubing in the kettle, and a plastic mash paddle, I wonder how you get a good whirlpool going?

 
Reply With Quote
Old 10-02-2013, 02:25 AM   #6
JustWeiss3
Recipes 
 
Sep 2013
Posts: 6

Biertourist, really appreciate such an in-depth answer. As for why I would think more protein would be a good thing for a better beer, that's not necessarily the case. For my own purposes I was curious if you could retain the nutrition of the pre-malted barley. The affects to taste/haze/etc non-withstanding I thought it'd be interesting project to brew a beer with a high protein content (and discover the consequences), and upon looking into it lead to the original question of where it all went. Adding some nutritional protein content to my brew seems like something the hasn't really been done.
Now that the original issue is cleared up I guess before I abandon the idea I'm wondering if say adding an amount of heat-stable whey protein to the wort would be a viable alternative, or if you had any other recommendations that you think would steer me in the right direction.

 
Reply With Quote
Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Where does the Protein Go? JustWeiss3 Beginners Beer Brewing Forum 3 10-01-2013 10:37 PM
Where Does the Protein Go? JustWeiss3 All Grain & Partial Mash Brewing 4 10-01-2013 05:34 PM
Too much protein!?!? Marshi Fermentation & Yeast 7 10-06-2012 07:25 PM
Pea Protein spaced Gluten Free Brewing 7 08-09-2011 08:39 PM
Protein rest? joelr Beginners Beer Brewing Forum 4 11-29-2010 04:42 PM


Forum Jump