When it comes to home grilling, people are either gas hot heads or charcoal purists, who have started a flame war that seems to have no conclusion to it till now. Grilling is generally utilized for three types of cooking. We have high heat direct radiation cooking, a setup in which the food is directly positioned above the source of heat. Steaks are prepared this way, usually without a lid over the meat. With indirect heat smoke roasting, the lid is kept closed when the airflow from the warm convection is made heavy with flavorful smoke from hardwood. With indirect heat convection roasting, we can cook whole roasts and chickens with the heat source off to the side as the warm air flowing around the closed lid cooks the food. This two-zone method is quite complicated for many as well as the second type of cooking described before. The real difference/s between gas and charcoal cooking lies in a number of factors.
The process of browning the surface of meats is called searing, which is how steaks are cooked. When searing is properly executed, chemical reactions occur and they include caramelization and the Maillard reaction, among others. Those two principal reactions are responsible for the production of sweet, complex, rich and savory substances on the surface of the grilled meats. A beautifully crunchy crust is also produced due to how searing dries the surface. Searing meats will not seal in their juices. For the perfect steak, what we actually want is a uniform sear from one edge to another and no grill marks.
Thanks to how it produces more direct infrared heat, a charcoal grill outperforms a gas grill in this aspect. I have seen some expensive gas grills equipped with special sear burners that can do an acceptable level of searing. And with the most expensive and popular steakhouses grilling rare aged prime beef on gas grills, the scales in this aspect have certainly tipped in favor of gas. Good quality gas grills used in the most expensive steakhouses produce a dark sear all over the food, which can only be achieved using high heat. Plenty of steakhouses have special broilers that deliver heat above and below at the same time at awesome blow torch temperatures. While regular gas grill burners are geared to deliver temperatures in just the 500°F range, a restaurant gas broiler sears the meat surface from 800°F to 1,200°F. The limiting factor for these types of grills is the small grilling surface.
On the other hand, a charcoal grill can dish out up to 900°F on the surface of a number of steaks at once, so we can easily host the barbecue party with confidence.
Smoke is yet another bone of contention between charcoal and gas grills. Although smoke is merely a flavorful byproduct of the process of combustion, the smoke from burning charcoal and gas is different. Charcoal produces more smoke compared to gas, and more smoke means a wider variety of tasty flavor molecules. Gas, being a simple molecule, creates no flavor during complete combustion. Only carbon dioxide and water are created. There will be a lot of smoke produced as the drippings from the food hit the heat sources below. Although gas grills have flame jets covered with lava rock, metal plates or ceramic rocks to shield the burners, absorb heat and give it off, the food is not directly exposed to the flame. Charcoal produces combustion gases when mixed with smoke from wood chips for a distinctive Southern barbecue flavor. Charcoal grills impart a deeper and smokier firehouse flavor and scent, but gas grills impart a better pork flavor and more moist food. In this aspect, taste is a matter of preference.