I had a bit of grain left during my last run, so I mixed the bits I had left.
This is interesting, actually. Over the next few months, I'll continue this experiment to see what grain mixes might work better for spawn.
While this wasn't a "proper" test, I had still hypothesized that the higher starch content in the popcorn would do better. I guess not.
I'll try and separate testing into different categories like starch content, moisture content, mycelium strain, etc. There is probably a ton more conditions to isolate as well.
I use rye berries and oat mainly, deer corn would probably be cheaper though...