What color is a correctly adjusted natural gas flame?

A correctly adjusted natural gas flame is characterized by a blue color. This blue color indicates that the gas is burning efficiently and completely, with an optimal air-to-fuel ratio. In a blue flame, the combustion process occurs with sufficient oxygen, leading to a hot and clean burn, which is essential for both safety and performance in gas appliances.

The appearance of a blue flame is an indicator that the gas is properly mixed with air and that the combustion process is occurring as intended. In contrast, a yellow flame may suggest incomplete combustion, which can result in the production of carbon monoxide, soot, and a higher level of unburnt gas. A green flame often indicates the presence of certain metal salts, which is not typical for a natural gas flame, and a red flame usually suggests low temperatures or poor combustion as well. Therefore, the blue flame is the ideal and safest indication of proper gas appliance operation.