If you choose to pick up your food hot, the food should be served immediately. You may set the food on a chaffing set with sternos; this will keep the food warm for 2 hours. If you pick up your food cold you must keep it refrigerated until ready to heat. Remember to allow enough time (at minimum one hour) to heat up your food before your event starts. Also, sterno fuel is used to keep your food warm; it is not used to heat up cold food.