When juices drip from food onto hot charcoal, it produces flavor because the resulting steam rises to season the food. Gas grills use several materials to produce the same effect. Lava rock heats quickly and disperses the heat to the interior of the grill. Lava is porous and allows grease to accumulate, lessening its efficiency and increasing flare-ups. Replace lava rock yearly or turn over to expose a fresh surface.
Pumice stone operates like lava but collects less residue.
Ceramic is more expensive than rock but lasts much longer. Heat Plates or bars are made of metal and allow heat to rise while dripping juices dissipate when they fall on the hot metal. The weight of a grill should be considered. Grills aren't sold by the pound, but remember that heavier gauge metal is more durable. Side burners on gas grills allow you to prepare an accompanying dish without running back and forth to the kitchen.