Cooking with Gas
Even the simplest gas grill is more complex than a typical charcoal grill. Common components of a gas grill include:
- Gas source
- Valve regulators
- Cooking surface
- Grill body
- Grill hood
The grill body houses all of the other components except the hood. The hood covers the cooking surface and serves to trap the heated air inside, which increases the temperature inside the grill.
The gas source is connected to the valve regulators via the main hose. The regulators are controlled by knobs that allow you to determine how much gas is allowed through the valve to the burner. Most grills have two main burners, with a regulator for each one. Each burner has a series of tiny holes along its length that the gas exits through.
Three things are required for a gas grill to ignite properly:
The gas is supplied from the propane tank or the natural-gas pipeline (more on this in the next section), and oxygen comes from the air. But where does the spark come from?
The spark usually is supplied by the grill starter, sometimes called the igniter. This is a push-button or rotating knob that creates a spark of electricity to ignite the gas. The starter uses piezoelectricity to generate a nice spark that lights the grill.
Certain crystalline materials (like quartz, Rochelle salt and some ceramics) have piezoelectric behavior. When you apply pressure to them, you get a charge separation within the crystal and a voltage across the crystal that is sometimes extremely high. For example, in a grill starter, the popping noise you hear is a little spring-loaded hammer hitting a crystal and generating thousands of volts across the faces of the crystal.
A voltage this high is identical to the voltage that drives a spark plug in a gasoline engine. The crystal's voltage generates a spark large enough to light the gas in the grill.
The burner is where all the actual burning occurs. It mixes the gas with oxygen and spreads it out over a large surface area to burn. Each burner has a pair of electrodes connected to the starter. When the starter's hammer is tripped, the resulting surge of electricity causes a spark to arc across these electrodes and ignite the gas/oxygen mixture. To create an evenly heated cooking surface, most gas grills have at least two separate burners.
Next, we'll take a look at the fuels most often used in gas grills.