Is there an ideal coffee grind for culinary (i.e. actual food, not beverages) use, particularly in dough? More particularly, when the coffee is the main ingredient (in matters of flavor)?
What effect, if any, does the kind of grind have on a solid recipe taking ground coffee?
This question appeared to me from a recipe of my own, which is Coffee Cookies (essentially a typical chocolate chip cookie, with cocoa, ground coffee, less flour and dark chocolate chips), in case it implies a more specific answer.
Best Answer
If you're putting the actual ground-up beans in the dough rather than brewing/extracting, I suggest one of two extremes, depending on the effect you're aiming for:
A very fine grind so it's evenly incorporated and not easily detected by feel (think of nut flour for the texture you'd be aiming for). As you're replacing some flour with coffee in your recipe this might be your best option.
Very coarse, more like cracked beans than actually ground. Then you get the pleasant* crunch of the beans, and the burst of flavour. If you were just adding coffee to a normal chocolate chip cookie recipe this would be better (IMO). This is what I'd do, but I rarely bake for coffee-lovers.
Anything in between could easily lead to an unpleasant graininess, while there's no advantage in terms of flavour over a fine grind.
* Pleasant to those of us that enjoy eating chocolate-coated coffee beans and similar things.