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-   -   What kind of Nitrogen is in wort? (http://www.homebrewtalk.com/f128/what-kind-nitrogen-wort-142308/)

Matt Up North 10-18-2009 09:32 PM

What kind of Nitrogen is in wort?
 
Yeast likes nitrogen, does anyone have any idea what kind of nitrogen is in wort prior to fermentation?

yorkbrew 10-18-2009 11:17 PM

If I remember right the nitrogen content is primarily coming from amino acids. I don't think it is the nitrogen that the yeasts go after so much as the amino acids. Nitrogen content is just how amino acids are measured.

david_42 10-19-2009 01:32 AM

Correct, that's why we don't worry about getting all of the protein out in the break.

crimpshrine27 10-21-2009 02:41 PM

Yeah mostly amino acids but also some di- and tri- peptides (2 or 3 amino acids joined together) ammonia and urea will be taken up in the beginning. These make up FAN (the measurment brewers and maltsters use). Some protein may be hydrolyzed by exogenous enzymes when or if these become depleted. FAN originates in malting, during the germination phase when endoproteinases hydrolyze the starch storage proteins (namely hordein) which gives you the ability to get a decent extract but also releases your amino acids etc. Some may also occur during mashing. Generally unless you want to use majority rice or maize then you won't have a problem with low FAN and problems may arise more from trying to increase it...

yorkbrew 10-21-2009 09:38 PM

Quote:

Originally Posted by crimpshrine27 (Post 1623327)
Yeah mostly amino acids but also some di- and tri- peptides (2 or 3 amino acids joined together) ammonia and urea will be taken up in the beginning. These make up FAN (the measurment brewers and maltsters use). Some protein may be hydrolyzed by exogenous enzymes when or if these become depleted. FAN originates in malting, during the germination phase when endoproteinases hydrolyze the starch storage proteins (namely hordein) which gives you the ability to get a decent extract but also releases your amino acids etc. Some may also occur during mashing. Generally unless you want to use majority rice or maize then you won't have a problem with low FAN and problems may arise more from trying to increase it...

Kudos on the specifics! What does FAN stand for, free amino nitrogen?

crimpshrine27 10-21-2009 11:16 PM

Quote:

Originally Posted by irate vermin (Post 1624445)
Kudos on the specifics! What does FAN stand for, free amino nitrogen?

aye that's right, yeah should have said! it's a bad measurement though, really broad and misses out on the detail. the devils in the detail... especially with FAN

yorkbrew 10-22-2009 05:20 PM

It always is isn't it? I suppose that is why I like this hoppy. Always something more you can be doing.

Matt Up North 10-25-2009 05:36 PM

I am following what you said up there. Wort contains "enough" nitrogen that we don't need to supplement it with anything. Is there anything that makes more FAN? Different base grains or more specialty or more roasted malts? I hear that stouts are healthier for the yeast than say a pale ale. Is that because there is a higher FAN and so the yeast are able to build their bodies big and strong? Or is it because there are other nutrients?

crimpshrine27 10-26-2009 06:55 PM

I can't quite comment at the moment between the difference of specialty malts except that I'd reckon that a better fermentation performance, if there is one, would probably be due more to an acidification in pH in the mash. I checked a maltsters website and there seems little or no variation in FAN between pale and dark malts. Remember it's contributed by the germination fraction of malting, not the final kilning. FAN levels can be limiting, I should have added before, in high gravity brewing. In these instances they increase FAN by adding yeast extract. (just don't use marmite).

FAN is really broad, it's a sum of parts from a possible 19 amino acids, 400 different dipeptides and 8000 tripeptides as well as purines and countless larger polypeptides (i.e. proteins). You can have the same FAN concentration on paper but it's made up of different stuff if you follow me...

there's also this other problem. These components don't all go into the yeast the same way. there are specific channels or "membrane permeases" in which they are transferred into the cell, which can cause problems because although one nitrogenous entity might be favorably taken up by yeast it is not necessarily the one which is needed. What can happen if you increase FAN is the yeast has to chow through all this unwanted stuff till it gets to the stuff it wants, this actually can slow fermentation during that first day of fermentation, "the lag phase".

Wort is wonderful stuff for yeast, and a load of other microbiological beasties to grow in. Oxygenation, Sanitation, Temperature and gravity/ABV are the most important factors in fermentation performance.


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