after the coffee has cooled...and be sure to flavor your coffee away from anything that you do not want to smell of pancake syrup...that includes yourself! One ounce flavors 2 lbs...so if you get this stuff on you are going to smell for days :wink:
As a purist, I never recommend flavoring coffee. But I will if asked. As Topher stated the flavoring is VERY strong and sticky. Also most of the flavoring is synthetic, and if you don't mind all the other fake stuff in your life, no need to be concerned about this either.