I brewed this 10 gallon batch of pumpkin ale in late september or early october 2012. I didn't use any cinnamon sticks in the boil or flame out. However, I don't see why you couldn't. I just mixed up a like 4 or 5 different kinds of ground spices. I put 3 short sticks in each carboy. When the beer was young, I wish i would have put more in, but I tried one of these last weekend for the first time since probably before Christmas. I was very impressed how the spices pushed through with age. It tastes way better now. This 10 gal batch was 20 lb 2 row, 1.5 lb of 40L caramel, and 1 lb of wheat, so it was rather light in malt character.... just for reference. I hope this helps a bit....I'm sure there are plenty more people on here that have more experience with using cinnamon sticks than me... maybe they can chime in, because I'd be interested in learning more about this too.