1. Make spent grain "flour": get a rimmed baking sheet (or 3) and spread 4 cups of spent grain on each sheet, this should get you about 1/4" deep which is usually half the depth of a standard rimmed baking sheet. Put them in the oven on the lowest setting you can get your oven to stay at (mine is 190ºF) and after two or three hours gently turn the grains over without spilling them all over the oven. Then leave them drying out with the oven on overnight. In the morning they should be crispy, kind of like an annoyingly healthy cereal. Throw them in a food processor and blitz them until they are a fine powder. This can be used to replace up to 15% of your standard flour. Because they've had most of the starches removed, doing so increases the fiber and protein content in whatever you're baking. I've heard numbers as high as a 50% increase in fiber and protein. I have made a sourdough starter which is far more robust than the one I had made from whole wheat flour, and I use it in breads and pizza dough.
2. Dog treats: 4 cups wet brewing grain, 4 cups AP flour, 1 cup peanut butter, 1 overripe banana, 2 eggs. Mix until it forms a paste. Grease a rimmed baking sheet with bacon grease (butter, oil of some sort, but dogs will not hate you if you use bacon grease) then spread the mixture evenly over the baking sheet. Precut your dog treats, bake for 2 hours at 350º, then lower the temperature to its lowest setting and let dry out for 10 hours or until crispy.
3: Compost the rest.
