Flare-ups happen when fat drips onto the heat source and catches fire. This causes carcinogenic PAHs (polycyclic aromatic hydrocarbons) to form and accumulate on your food. Meat licked by flames also tastes “off” and flames may char the outside of food before the inside has thoroughly cooked. To reduce flare-ups, select lean cuts of meat, trim excess fat and remove poultry skin. And, keep a squirt bottle of water near the grill to quickly douse any unexpected flare-ups.