Indirect heat means that there is a barrier between the heatsource and the food. In the WSM as it is designed to be used, you are cooking with indirect heat because the water pan, whether you're using sand, water, or an empty pan, is placing a barrier between the fire and the food. If you were to leave the waterpan out COMPLETELY, as some of us occasionally do, you would be cooking with direct heat, as the food is directly over the hot coals with no barrier. You get an additional flavor layer when cooking slowly over direct heat because of the meat drippings that fall on the coals. "Traditional" barbecue is done over direct heat, as the meat is cooked 18 - 24 inches (depending on how you learned to do it) over a bed of coals that is periodically refreshed throughout the cook. That's the way my daddy, my grand-daddy, and my great-granddaddy cook whole pigs in the South Carolina low country. Our Okie trailer rig, on the other hand, is indirect heat as it has a log-buring firebox on the side rather than a repository for burning coals directly under the meat.
Most recipes that I've seen that indicate "indirect" heat are referring to smoking temperatures, ie 225 to 250. If you'll post the type and amount of meat in your recipe and the recommended cooking time that it gives, we can probably back into it for you.
D@mn. I still can't wrote a short post. You'd think I'da learned by now. /infopop/emoticons/icon_rolleyes.gif
Keri C, still smokin on Tulsa Time /infopop/emoticons/icon_wink.gif