Once the burner has been lit, the flame should be adjusted so
that a bluish flame containing two or more cones is visible.
In order to adjust the burner, first adjust the height of the
flame by opening/closing the gas control valve. A proper flame
should be the smallest flame necessary for the task being performed.
A flame that is about 5-8 cm tall is sufficient for most tasks
in the laboratory.
Then adjust the air control vent until the burner flame is blue
and contains 2 or more distinct cones (see IMAGE below). Yellowish
flames are a result of insufficient oxygen in the gas mixture.
Oxygen flow can be increased (reduced) in the gas mixture by adjusting
the air control vent.
Note: When adjusting the air vent, be careful not to exitinguish
the flame or completely unscrew the burner tube.
Why should the flame be a bluish color containing two or more cones? Answer
The bluish flame indicates that the gas mixture has been optimized and thus, the flame is at its highest possible temperature.
Temperature ranges of each colored cone:
part of the flame
inner blue cone
outer blue cone