Did you knead it fully after mixing up the dough? Did you use a stand mixer to make it?
I've made two batches so far, both came out well (second was better)... I used the recipe posted in the thread on the boards here...
Basically its:
3 cups spent grain (I send mine through the food processor to get the grains smaller, spinning about 4-5 cups to get 3)
1.5 cups reserved wort (from the brew the grains came from)
1 packet dry Baker's yeast (normal active yeast)
3-4 ounces of honey
3-5 cups bread flour (sifted)
1.5 tsp salt
soft butter (3-8 TBS, adjust to your liking)...
I use the wort for the yeast starter (I put the honey in there)... Once the yeast is going at it for a bit (15-30 minutes is usually enough, but YMMV), I spin the grains in the food processor and add them to the mixer bowl... I add the yeast, butter and salt at that point too... Get that all mixed well before you start adding flour. You might use more, or less, flour depending on how much liquid is in the starter, as well as how much butter you use. Once it comes off the dough hook, transfer to a board and knead it until it's "right"... Let it proof once, then form your loaves, letting it rise again before you bake it (until it's increased in size about 50%).
I bake mine at ~375F for 25-35 minutes (had one done at 25, the other at about 30-35 in the last batch). I also use a pizza stone to bake them. I bake one at a time, so that I don't have to worry about uneven cooking, or moving them around too much. I do rotate the loaf 180 degrees, once, while it bakes (at about half way through the time)...
If you used sourdough for the recipe, I have no idea how it would impact the bread. I've never made sourdough before, and probably never will.
In my last (or second) batch, I used double the yeast, and a little larger starter, since I was going to freeze some of the dough. That made for a really good first baking (baked two loaves, saved about 6 smaller dough balls)... I might do that for future batches too, or use more yeast to flour (reducing what's needed to make it work) to get a lighter bread.