Why wicks matter more than wax

A wick is a pump: it draws liquid wax up to the flame to be burned. If it is too small, the flame drowns; if too large, it flares and gives off soot.

We test each new jar with three or four wick sizes. The right one makes the wax melt just to the edges of the jar after a couple of hours.

Cotton wicks need trimming to about five millimetres before each burn.