Gas ovens have been in existence since the 19th century, when British inventor James Sharp began to commercially produce them after successfully installing one in his house. However, because of the time it took to create an adequate gas pipe network, it wasn’t until the 1800s that gas ovens became commercially successful. Many improvements have been made since that early model, including a thermostat to help with temperature control and an enamel coating to make cleaning easier, and today gas ovens can offer a huge number of features, including self-cleaning, convection fans, and automatic meat thermometers.
A gas oven is most often topped with a gas-powered cooktop but it can be installed in a separate area to the cooktop if that is more convenient. Gas ovens generate heat not with an electric coil as with electric models, but via gas-fuelled burners. There are two types of ignition - a pilot flame and an electric ignitor - but most modern gas ovens use electricity to trigger ignition.
Gas ovens with pilot ignitions have a small, continuously burning flame which gets bigger when the thermostat is turned on. The flame can then envelop the thermocouple bulb of the oven safety valve, which, in turn, opens to allow gas to flow to the pilot flame, igniting the burner.
When you turn the control knob to the desired temperature, a battery or mains-powered electronic circuit sends an electric current to the ignitor. This heats it and opens the valve to allow the natural gas to flow through a burner tube and across to the burner at the bottom of the oven where the ignitor ignites it. The thermostat then monitors the rising temperature of the oven.
The burner in the oven is controlled by a thermostat - when the oven has reached the temperature selected, it will turn itself off by shutting off the voltage to the ignitor, which triggers the safety valve to shut off the gas supply to the burner. The flames will remain extinguished until the temperature starts to drop, at which point the oven will turn itself back on again until it’s once more up to the correct temperature, and this cycle repeats throughout the cooking process in order to maintain the correct temperature.
Conventional and convection
Conventional ovens use only the burners to heat food, meaning that there can be cooler spots which can lead to uneven cooking. Convection ovens employ the use of a fan to circulate the heat around the oven evenly.