What should the color of a properly burning gas flame be?

A properly burning gas flame should ideally be blue. The blue color indicates that the gas is burning efficiently and completely, meaning that there is a proper mix of fuel and air. In this state, the combustion process produces a clean flame with minimal production of carbon monoxide and other incomplete combustion byproducts. This blue flame signifies that the gas appliance is functioning correctly and safely, providing optimal heat output while minimizing waste and emissions.

In contrast, a red or yellow flame often indicates incomplete combustion, which can occur if there is insufficient oxygen for the gas to burn properly. This can lead to the production of soot, carbon monoxide, and lower heating efficiency, posing safety risks. A green flame is typically associated with the presence of certain metal salts, which can indicate contamination rather than a proper burn. Thus, the blue flame is the optimal color to confirm a safe and efficient gas combustion process.