I came across What purpose does coffee serve in a chocolate cake recipe? as a similar question to one I'd just asked about baking.
Looking at the recipe she provided there, wouldn't the amount of liquid (coffee, buttermilk, oil, and eggs) to solid (flour, sugar, and cocoa powder) make it a very runny batter? It's 4 1/3 cups liquid plus 3 eggs to 6 1/2 cups solid (if I count the sugar as a solid). It just seems like a lot of liquid to solid. Maybe the coffee being hot does something?