Making a dog’s breakfast of your beer mash
Every all-grain brewer knows the moment. The wort is in the kettle, the boil is rolling, and you look back at the mash tun and think, that is a lot of grain. Warm, fragrant, and spent. It did its job. The sugars are gone, the enzymes are done, and what remains is mostly husk, fiber, and protein.
If you ever finished brewing your beer and wondered what to do with that mound of spent grain, you are not alone. Dumping it feels wasteful, especially after spending so much time dialing in mash temperature, runoff speed, and sparging technique.
The good news is that spent mash still has value. Not brewing value anymore, but culinary and practical value. It can go into bread, crackers, compost, gardens, or livestock feed. And yes, there is one option that tends to make tails wag.
You can turn it into dog biscuits.
This works because spent grain is rich in insoluble fiber and protein, but low in fermentable sugars. That makes it filling, aromatic, and safe when handled properly. The same husk structure that helped you lauter cleanly now gives texture to baked treats.
Spent grain dog biscuit recipe
- 4 cups of spent grain mash
- 4 cups of plain flour
- 1 cup peanut butter, or oil, or plain pizza sauce
- 1 egg
Mix the ingredients thoroughly until you get a stiff, workable dough. If your mash was very wet, you may need a little extra flour. If it was well-drained after lautering, the proportions above usually land just right.
Roll or press the dough out and cut into typical dog biscuit shapes. Place them on a lined baking tray.
Bake at 350F or 180C for 30 minutes. Then reduce the oven temperature to around 225F or 110C and leave the biscuits in until they have fully dried out. This second, low-temperature stage matters. Dry biscuits last longer and are safer for storage, just like drying malt prevents spoilage.
A note on hops and mash safety
It has been pointed out by many brewers and veterinarians that hops can be harmful to dogs, particularly certain breeds. Do not use spent grain from a mash that was first-wort hopped or otherwise exposed to hops. Mash-only grain from standard lautering is the safe route.
This is another quiet reminder of good mash practice. Clean separation, controlled runoff, and proper sparging do not just improve beer. They also leave behind grain that is easier to repurpose.
Other smart ways to reuse spent mash
- Feed it to chickens or pigs, who love the texture and warmth
- Add it to compost, where the fiber breaks down slowly and improves soil structure
- Work it directly into garden beds as organic matter
- Scatter small amounts for birds, especially in colder months
- Incorporate it into your own bread recipes for nutty flavor
- Turn it into crisp beer crackers
Using spent mash well is part of brewing discipline. You already took the time to run off slowly, sparge patiently, and protect the grain bed. Let the end of the process show the same care.
Well done for recycling food that already gave you beer.
And while you are at it, treat yourself to an analysis of the themes of Blade Runner 2049 + you might ask yourself, how many weevils are in your grain right now?