I recently brewed my second and third batch of a nice stout I've made before. I thought it could use more of a chocolate flavor or taste. Not knowing how much, I added 1 oz. of cocoa powder during the boil. 1 oz. of cocoa was almost half a coffee cup. You must have emptyed the can. Regardless, since I have two identical 5 gallon batches that were made within two days of each other and I've had to pull the gravity on each and of course tasted both, I can tell you the cocoa added batch has slightly different taste in the uncarbonated form. In the future, I'll add eight ounce of maltidextorse to bring out the chocolate taste and depending on the final flavor, maybe a little more cocoa.