Gas barbecue grills designed for use with lava rocks disperse heat more evenly than merely relying on gas jets to do the cooking. Properly cleaning, arranging and maintaining the rocks is essential to efficient grilling with minimal flame flareups that can burn food and cause unwanted fires inside the grill. Attention to detail and regular changing of the rocks also enhances the grilling experience with these porous pieces of nature.
Pour the lava rocks packet that accompany the new grill into a large plastic bowl or bucket. Fill the bowl with water using an outdoor garden hose, allowing the bowl or bucket to overflow for several minutes while stirring the rocks slowly with a stick or trowel. This rinses away any debris or factory dust. Empty out the water and allow the rocks to dry out in the sun atop a towel.
Place the lava rocks in a single layer, completely covering the rock grate inside the grill. The rock grate is the metal grid that rests directly above the gas burners and several inches below the cooking grate. Stacking the rocks higher than one layer causes uneven heat distribution.
Flip the rocks over after every five or six grilling sessions. This allows grease that collects in these porous rocks to burn off, reducing grill flareups.
Replace the lava rocks after every one or two grilling seasons to prevent major grease build-up and promote efficient heating in the grill.
Look for replacement lava rocks at hardware or grilling supply shops. Don't stack thick layers of the rocks on the lava rock grate as most barbecue grills designed for use with lava rocks heat more efficiently with a single rock layer. For added flavour, soak wet hardwood smoking chips in water for an hour, then fashion a foil pouch around the chips and poke holes in the pouch with a fork to ventilate. Place the pouch directly upon the lava rocks to create wood smoke for flavouring meat during grilling.
Always allow lava rocks to thoroughly cool following grilling sessions before turning them or performing other maintenance. Always wear heat-resistant grilling mitts when handling hot grill lids or grates, and use long-handled spatulas or tongs when moving or removing food from the cooking grate. Only use lava rocks in grills equipped with rock grates and designed for use with lava rocks. Using the rocks in some grills can damage the interior and inhibit gas burners.