Protein levels in spent grain?

Aussie Home Brewer

Help Support Aussie Home Brewer:

kierent

Well-Known Member
Joined
2/8/09
Messages
158
Reaction score
8
Hi all
I have been giving my spent grains to my parents to feed the chooks with. They love it, but they were asking if I knew what the protein level is in it, because apparently to keep chooks on the lay their main feed needs to be around 16% protein. The interweb tell me that barley only starts at around 12% protein anyway.

This would probably be acceptable as a bit of a supplement for the chooks, but my question is, does the mashing and sparging process remove any of that protein? My understanding is that enzymes convert starch to sugars during the mash, but I'm not sure what this process means for protein. If protein is also reduced then it's probably not a great thing for the chooks if we want them laying.

Any knowledge out there?
 

MHB

Well-Known Member
Joined
1/10/05
Messages
5,861
Reaction score
3,278
Location
Newcastle
Interesting one
There is some protein in expended malt and some in the beer to. The reason maltsters and brewers choose low protein barley to make malt is to reduce the amount of protein that ends up in the finished beer.
Any decent COA (certificate of analysis) will give a Nitrogen value (Protein = 6.25*N value) or a total protein, it will usually give a soluble Nitrogen or protein value to.
12% protein is very much at the high end of acceptable, premium malt will be less.
Have attached an old COA for Weyermann Pilsner. You can see the protein levels down the bottom.

Been a long time since I studied Ag and Animal husbandry at school (1975-6 cor I'm starting to hurt in places I didn't used to have). Many breweries sell malt (well the bigger ones) or give it away to farmers. The protein content of expended malt might not be all that you want but remember it provided a lot of roughage, some protein and sugars and other carbohydrates, and if its free.
If you include your hot break and expended yeast it starts to look a lot better as an animal feed.
Mark

PS
The Kolbatch number at the bottom of the protein (40.6%) is the amount of total protein that ends up in the wort at the end of the standard laboratory mash (congress mash), In this case, its 40.6% of the 10.6% of the mass of the malt that is protein, just shy of 60% stays in the expended malt.
M
 

Attachments

kierent

Well-Known Member
Joined
2/8/09
Messages
158
Reaction score
8
Thanks MHB, that's interesting and very helpful. Looks like most likely the grains I'm giving them won't have the required levels of protein for laying hens. But they're looking at getting lambs and pigs too, and I know pigs love spent grains. You're right, if I were to chuck in the hot break and yeast it would be a good source of free food. For now I might suggest they just give the spent grains to the chooks a bit at a time so they're mainly eating their high protein laying pellets, which I assume are formulated specifically for laying hens.
Cheers
 

yankinoz

Well-Known Member
Joined
16/2/12
Messages
591
Reaction score
182
For the first time I can remember, I disagree with MHB. Spent grains are higher in protein than the usual feed grains. Thanks for his observation that 60% of the original protein remains in the spent grains. So that's typically about six percent of the original grains' dry weight. The exception would be if mash efficiency is very low.

What he is not taking into account is that malting has converted most the carbohydrates (other than cellulose in the fibre) to sugars, and lautering and sparging have removed most of the sugars. In a low-protein (10%) barley those carbohydrates make up about 70% of the original grain. If mash efficiency taken through sparging (later losses that go into brewhouse efficiency are irrelevant in this calculation) is 85%, then the spent grains retain about 40% of the original dry weight. Our hypothetical spent grain contains by dry weight 6 x (100/40) = 15% protein.

Because the fibre content is very high, farmers I've heard from who feed spent grains to pigs or chooks usually mix them with unmalted grains to prevent diarrhoea.
 
  • Like
Reactions: MHB

MHB

Well-Known Member
Joined
1/10/05
Messages
5,861
Reaction score
3,278
Location
Newcastle
Fair point, didn't think it through far enough.
Just remember that, that is on the dry weight of the expended malt, not the wet mass. Obviously malt goes in fairly dry and comes out very wet.
Mark

Edit
Just went and did a bit of Googling, this looks like a fairly readable link Barley distillers grains, whisky production, fresh | Tables of composition and nutritional values of feed materials INRA CIRAD AFZ
Refers to expended distilling grist but shouldn't be too far from what we could expect from brewing waste. Again its based on dry weight.
M
1587081238495.png
 
Last edited:

yankinoz

Well-Known Member
Joined
16/2/12
Messages
591
Reaction score
182
Fair point, didn't think it through far enough.
Just remember that, that is on the dry weight of the expended malt, not the wet mass. Obviously malt goes in fairly dry and comes out very wet.
Mark

Edit
Just went and did a bit of Googling, this looks like a fairly readable link Barley distillers grains, whisky production, fresh | Tables of composition and nutritional values of feed materials INRA CIRAD AFZ
Refers to expended distilling grist but shouldn't be too far from what we could expect from brewing waste. Again its based on dry weight.
M
View attachment 117931
To get that percentage of protein, presumably they're using grain with >10% protein, get very high mash efficiencies and sparge thoroughly. For most home brewers, <20% in the spent grains is probably closer.
 

MHB

Well-Known Member
Joined
1/10/05
Messages
5,861
Reaction score
3,278
Location
Newcastle
Oh I agree, note the "Total Sugars" in the table, 0.5% - that's well sparged and not leaving much behind, for beer wort I would expect a bit more, extracting tannins isn't as much a concern for wash makers.
Even the column "AS Feed" is probably a lot dryer than home brewers expect.
Mark
 

Ballaratguy

Well-Known Member
Joined
21/6/17
Messages
197
Reaction score
55
For the first time I can remember, I disagree with MHB. Spent grains are higher in protein than the usual feed grains. Thanks for his observation that 60% of the original protein remains in the spent grains. So that's typically about six percent of the original grains' dry weight. The exception would be if mash efficiency is very low.

What he is not taking into account is that malting has converted most the carbohydrates (other than cellulose in the fibre) to sugars, and lautering and sparging have removed most of the sugars. In a low-protein (10%) barley those carbohydrates make up about 70% of the original grain. If mash efficiency taken through sparging (later losses that go into brewhouse efficiency are irrelevant in this calculation) is 85%, then the spent grains retain about 40% of the original dry weight. Our hypothetical spent grain contains by dry weight 6 x (100/40) = 15% protein.

Because the fibre content is very high, farmers I've heard from who feed spent grains to pigs or chooks usually mix them with unmalted grains to prevent diarrhoea.
How do you know if a chook has diarrhoea ๐Ÿ˜‚๐Ÿ˜‚๐Ÿ˜‚๐Ÿ˜‚๐Ÿ˜‚
 

Blackman

Well-Known Member
Joined
16/12/16
Messages
49
Reaction score
12
It either has firm shit or runny shit.....
Fairly straightforward I would think.
 

Outback

Well-Known Member
Joined
14/4/18
Messages
70
Reaction score
55
Location
Betoota
A by-product of the ethanol industry is a product marketed as DDG (dried distillers grain), this typically runs around 20% protein for the reasons discussed above, but can vary wildly depending on the original grain which was malted and then fermented.
The DDG is sold as a meal or some of the extracted syrup is added back and it is then pelletised and sold as stock feed. The last load I got I paid over $500 tonne for during the peak of the drought, so hardly giving it away, especially when buying 42 tonne every month or so.
Feed it to your chooks with gay abandon, they'll love it, and a bit of greenery added will make them happy cluckers.
 
  • Like
Reactions: MHB

Ballaratguy

Well-Known Member
Joined
21/6/17
Messages
197
Reaction score
55
It either has firm shit or runny shit.....
Fairly straightforward I would think.
Never seen any Bird shit thatโ€™s been firm....maybe slightly less runny but still runny
Actually it might be a good thing that fords have runny shit otherwise we might get knocked out when the shit on us๐Ÿ˜‚๐Ÿ˜‚๐Ÿ˜‚๐Ÿ˜‚
 

MHB

Well-Known Member
Joined
1/10/05
Messages
5,861
Reaction score
3,278
Location
Newcastle
Never seen any Bird shit thatโ€™s been firm....maybe slightly less runny but still runny
Actually it might be a good thing that fords have runny shit otherwise we might get knocked out when the shit on us๐Ÿ˜‚๐Ÿ˜‚๐Ÿ˜‚๐Ÿ˜‚
Yes always felt that about Fords... good to see I'm not the only one who gets caught out by autocorrect, well crap speller to, which probably doesn't help.
Mark
 

Blackman

Well-Known Member
Joined
16/12/16
Messages
49
Reaction score
12
How did this turn to cars? As a Ford man I can only say 'at least they are still being made'.
Back to talking shit though, my chooks get kitchen scraps inc meat, free range grazing, pellets and spent grain. Their shit is......well not firm but more like soft serve from macas, as in it hold its own, certainly not runny.
 

Grmblz

Well-Known Member
Joined
19/6/17
Messages
523
Reaction score
316
Location
Far South Coast NSW
It's not about cars, it was an "autocorrect" a bit like "shit" used to come out as "shiv" I'm not sure why the sensitive programmers thought a knife designed to kill people was more acceptable than a natural bodily function but that's political correctness for ya. :rolleyes:
 

Latest posts

Top