When you bake enough chocolate cakes, or simply look at enough chocolate cake recipes, you’ll notice a trend: many of them include coffee or instant coffee as an ingredient. This isn’t because most people are looking for a mocha-flavored cake. Rather, coffee is commonly included because it is a great way to enhance the flavor of cocoa powder, resulting in a more chocolaty cake – not a coffee-flavored one.
Cocoa powder is a bit bitter on its own, with hints of fruit and spice that are detectable when you get a good-quality cocoa. Coffee has these same flavor elements, and a small amount of coffee in a cake batter – whether you’re using 1 cup of coffee or 1 tbsp instant coffee – will help these cocoa flavors stand out even more than they would on their own. The milk, sugar, eggs and so forth that you add into a cake just helps all that cocoa taste good, not necessarily more chocolaty! You would have to add quite a bit of coffee (or not have much cocoa at all) to get more of a coffee flavor than a cocoa one; chocolate is generally more dominant in a baked good than coffee is.
What all comes down to is that even if you’re not a fan of coffee, having some instant coffee in the cupboard can give a little extra boost of flavor to a chocolate cake and take it from good to great. You can keep a small container of freeze-dried coffee almost indefinitely. Still, if you’re really opposed to adding coffee in any form, you will be glad to know that you can always leave it out. If a recipe calls for coffee, just add water (as coffee is just flavored water) and if it calls for powdered coffee, simply omit the small amount called for altogether, just as you might use less cinnamon if you’re not a fan of it in a cake or cookie.