I am building my first SFG and have just completed a batch of Mel's mix. I used 1/3 peatmoss, 1/3 compost, and 1/3 vermiculite. My composed was 1/3 aged horse manure, 1/3 mushroom compost, and 1/3 leaf compost. It was in a pile for a couple hours before I began moving it to the garden boxes and I'm noticing the mix is "hot" (it's warm and steaming). My question is should it be this way?

Using traditional gardening this seems too much compost to me, but that is why I am trying SFG, it's not the traditional gardening. Is my compost not aged enough? Is it just a temperary reaction with the peat moss? Last thing I want to do is ruin all my transplants with too hot of soil. Someone please help. Thanks