Nothing could be easier than lighting a gas grill, but here, too, there’s a science. First and foremost, always open the lid of the grill before you turn on the gas. Failure to do so can result in a gas buildup and subsequent explosion. I have seen this happen, so please, please, unless the manufacturer’s instructions specifically indicate otherwise, always open the grill before turning on the gas.
On some models, the igniter is keyed to a specific burner tube. You must light that tube first, before lighting the rest of the grill. Again, follow the manufacturer’s instructions. Then preheat your grill to the desired temperature, generally high for direct grilling and medium for indirect grilling. Some gas grills have a hard time getting hot enough for proper searing. To ensure maximum heat, I always preheat a gas grill until hot (15 to 20 minutes), then let it burn an additional 10 minutes to get really good and hot.