From bbq.about.com
Some of you purists / gurus in BBQ-ing probably wouldn't dream of using BBQ sauce while smoking, but from a beginner/mild intermediate BBQer's standpoint, I've smoked quite a few boneless breasts on my Big Green Egg, using soaked mesquite chips and brushing alot of store-bought BBQ sauce on beforehand. If I keep the smoker temp. at 200-250, those things are GREAT when they come off. Just some info. for any beginning smokers out there...Most of the things we call barbecue sauce contains sugars. Sugars burn at a temperature of about 265 degree F. If you are cooking above this temperature then the sugars in a sauce will burn and add a bad flavor to foods. Since smoking is typically done at much lower temperatures then you don't have to worry about adding barbecue sauces to meats during their smoking times. You might get some caramelization of the sugar but it won't burn and it won't cause you any real problems.