I'm currently at work (!!) but I wanted to go ahead and write down the recipe I used for spent grain bread last night. I think I might be getting close to a final product and I don't want to forget it!
Sponge:
1/3c honey, warmed
1/2c water, warmed
1c whole wheat flour
1c spent grains
4tsp active dry yeast
Dough:
1 egg
1/4c olive oil (or butter)
2c spent grains (food processed)
2c whole wheat flour
1c bread flour (plus extra)
2tsp salt
5tbs vital wheat gluten
Start by warming 1/3c honey and 1/2c water (or milk, if you're not on an alpha-gal diet like me) to around 100-110°. Don't go over 120° or you'll kill the yeast. Add that to 1c whole wheat flour and 1c spent grains, mix well. Then add the yeast. You'll need something crazy like 4tsp because of all the grains. Let this sit somewhere warm for about an hour. I usually turn my oven on for about a minute then turn it off and let it sit inside.
After the sponge has fluffed up, add 1 egg, 1/4 cup of olive oil, 2 cups proceed grains, 2 cups sifted whole grain flour, 1 cup sifted bread flour, 2tsp salt, and 4tbs vital wheat gluten. Mix in the wet ingredients, then the dry. Start kneeding the dough and add more sifted bread flour until the consistency is right. I think this recipe ends up with a slightly-too-sticky dough and I always want to add more flour, but it would end up too dense.
The dough should kneed for 10 minutes on speed 2 in a mixer. Can't say how long you should kneed by hand because I don't do it that way. Once the dough is kneeded, roll it in a ball, and place it in a greased bowl to rise. I also put wet paper towels over the top to prevent drying. Again, I warm my oven slightly and let it rise inside.
It should rise for about an hour before you punch it down. Divide the dough into two even loaves. If you like free-form bread, shape as desired, set on greased pan and let rise. If you like nice, sandwich-shaped bread, pat the dough out into a rectangle about 9" by 12". Roll the dough into a pipe type shape then tuck the ends under. This will give you a nicely-shaped loaf.
Again, let the dough rise in a slightly warm oven for AT LEAST an hour. The dough won't rise much more during baking so you should essentially let it rise all the way to the size you want your loaf to be before cooking. Bake the bread at 375° for about 45 minutes. Because it's a pretty hardy bread, you'll want the internal temperature to reach 205° to 210°.
One important consideration for the whole wheat to bread flour ratio is the type of grains used in your beer. When I made bread out of the British Nut Brown grains, the bread was MUCH heavier and darker and really couldn't handle a 3:1 ratio. Essentially, the lighter the color of the beer, the more whole grain flour you can use. But, when you have darker malts, like the chocolate malt in the Nut Brown, you need to decrease the amount of whole wheat flour in favor of bread flour to compensate for the grains.
Pictures will be up shortly!