Rinse chicken thoroughly. Season inside and outside with salt, pepper, and garlic. Using can opener, open beer can. Place chicken upright on can, so can is inside chicken cavity. Place on a roasting pan and roast in a preheated 350 oven for 50 to 60 minutes or internal temperature of 150 degrees F. Glaze with BBQ sauce and finish cooking on grill.
Combine all ingredients in sauce pot and simmer until reduced by 1/3 of the original volume. Cool completely and pack for transport.