I tried to make dog biscuits with my spent grains, but it was not a big success ;-) I read that we could make more beer reusing the grain again. I liked the idea of making a lighter version of the beer this way.

If I make an all grain stout, what can I expect to be able to do by reusing the grain?

1- Can I only add some more 2-row to a new mash to raise the OG, letting the flavor and color coming from the crystal and chocolat malt that was already mashed once? I believe I would get something close to an amber beer.
2- Or is it possible to just batch sparge again and start from there?

Anyone has tried this?

  • 1
    Since I don't have a full answer for your question (not sure about 1.) Here is a link to this technique called "parti-gyle". I've done a porter and light brown, but honestly only porter ended up being good.
    – rondonctba
    Commented Jul 11, 2017 at 4:14
  • @rondonctba: That's possibly because the different worts from the parti-gyle are normally not used as is, but combined with each other to obtain different strength beers.
    – chthon
    Commented Jul 11, 2017 at 11:37
  • @chthon Well, I've seen both "use cases", but yeah maybe I did not fully understand the technique.
    – rondonctba
    Commented Jul 11, 2017 at 13:34

3 Answers 3


I use second runnings / Parti-Gyle as often as I can. But as my primary mash efficiency rises theres less and less usefulness in the parti-gyle. As for me using the grains, it's compost or given away for chicken feed.

If your mash efficiency is still below 85% there's still plenty use in the parti-gyle.

I could usually get 5 gallons of 1.025-1.030 parti-gyle wort from a 12 gallon high gravity primary brew mash.

How to:

Slow Fly sparge for primary keeping mash water 1inch above grain. When primary beer is done sparging, stop the fly, stir and let the parti-gyle rest. When done with your primary boil, then batch sparge the parti-gyle wort.

Uses: Anything bellow 1.020 isn't very useful by its self. Most uses require adding a little DME, grain steep or sugar to bump it to the range you want.

Parti-gyle wort is low gravity and has many historical style uses like scottish-60.

It's great for starter wort. I boil and adjust to 1.040, Then refrigerate and strore in 1 gallon jugs.

It's great for malted ciders /light graffs, I find it even eliminates need to backsweeten. Especially if you steep in malts.


Don't mash out instead keep sparge around 154°, if you intend to allow the second mash to rest.

Adding a little more grain to second mash helps kick start a second conversion rest.

Add adjuncts to boost gravity.

Boil down to increase gravity. Usually pretty easy to get a fast violent boil since its usually 1/2 your normal volume.

Press the grains as the parti-gyle volaufs. I use a potato masher, works pretty well.

All in all how useful your parti-gyle is depends on a lot of factors and what its used for. I've only touched on the processes and uses as an overview.

  • 1
    I 2nd EZs comments. I do the same
    – RAReed
    Commented Jul 11, 2017 at 15:30
  • 2
    I have tried several times to reuse mash grains. I had some minor success reusing the grains used to make a strong ale (OG 1.062) which made weak wort that could be added to another brew. My attempts to re use the grain from a session beer yielded nothing useful and seemed to be a waste of time. Commented Jul 11, 2017 at 18:45

Wow! That is economical brewing - but possibly too economical. There may be some colour and flavour left in the roast grains but there should be very little starch, malto-dextrins or sugars left in the malted grains. However there is a lot of grain husk left behind and that is a source of tannins and lignins that impart a bitter or more astringent taste to the wort.

So one might be able to make further use of some part of the steeped/mashed grain but one would necessarily have to add more malted grain and one runs the risk of making a strangely flavoured and astringent beer. As the only reusable part (roast grains) are relatively cheap there is little to be saved and lot of effort to be used to make a possibly inferior brew.

IMHO it would be better to attempt to make more efficient use of the roast grain in the first steeping/mashing process than to attempt to make use of any remainder in a second processing.

  • I also think this might not be worth it, but I just wanted to ask before (if) I ever try it.
    – Philippe
    Commented Jul 11, 2017 at 13:02
  • Let us know the result. :)
    – rondonctba
    Commented Jul 11, 2017 at 13:31
  • 1
    At best I might be tempted to steep the used grain in warm, slightly acidic water. A very slight acidity will help keep tanins and phenols out of solution and the cooler water might take as much of the remaining roasted grain flavour as might be had. If suitable, I might then use that water to mash or sparge the next batch. If you carry out your idea, it would be interesting to know how it turns out. Commented Jul 11, 2017 at 13:35
  • 1
    I doubt on the homebrew scale you would extract enough tannins to make a noticeable difference (suggest: Exbeeriment?) if you were watching your gravity, mash PH, water chemistry, etc. It may be a lot of work/time (ie boiling) to get a usable amount of wort. I usually cap the mash with some 2-row for the 2nd mash rest. The 2nd brew is lower OG, but I have not noticed tannin.
    – RAReed
    Commented Jul 11, 2017 at 15:37

IMO, the best use of spent grain is for food.

I made an amazing bran cake from the spent grain from a red ale. Not only are the grains. Spent grain has residual sugars that add a sweetness that improves a lot of foods. You can use them in pancakes, cakes, muffins, and you can even make granola with it.

Once you are done mashing/steeping, place your spent grain on a baking sheet lined with baking paper and place in the oven at a low heat with the fan for a few hours, turning the grains every so often to get the to dry out evenly. Once dry, put them in a blender or a coffee grinder, and then you are done! Enjoy your beer with snacks made from the grains.

  • Indeed, making flour seems also a good idea.
    – Philippe
    Commented Jul 18, 2017 at 13:16

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