At last tasting my citrus kolsch was slightly lacking in the citrus department. It got 0.5oz of bitter orange peel, 0.5oz of sweet orange peel, zest of two lemons, and 0.5oz crushed coriander with 10 mins left in the boil, and I really thought that would be enough. I want to enter it in NHC as a fruit beer, and I may need to give it a little extra lemon or orange oomph in the keg. We'll see, as carbonating might bring out the citrus. It will get bottled of course, so I want this to be unfermentable. They don't seem to make orange or lemon extract for beer/wine but they do make both for baking. Another thought was grand marnier. Also, possibly "dry hopping" with zest.