No expert here. I have always tried to keep my worn castings moist until used. Have always had better luck. I believe that drying your casts either kills off or makes go dormant the bulk of the benificial microbes.
I have used dry and wet casts from the same bin harvested at the same time in side by side rows in the same raised bed. Let a buckets worth of casts dry out accidentally. The row with the wet casts showed a noticeable difference in the size and vigor than the rows that I used the same but dried casts. This was done on beans, tomatoes and cucumbers.
I don’t know if it kills off the microbes or by making the microbes go dormant it creates the noticeable lag in the above mentioned veggies. Not that the dry casts didn’t provide an adequate fertilizer, but the wet cast rows were better across the board; size, color, number of fruit, and less bug damage were observed.
I really enjoyed the carbon info Marco posted above.
