Cocoa powder can be added to beer during the boil, at flame-out, or even during fermentation to impart a chocolate flavor. Adding it to the boil is a common method, as it helps the cocoa powder to dissolve and disperse in the hot wort, resulting in a more integrated flavor. Some brewers also choose to add cocoa powder to the fermenter, either in the primary or secondary fermentation, for a more subtle chocolate flavor.