1. The first burn matters most

Let the wax melt all the way to the edges before blowing it out — about one hour for every 2.5 cm of the jar's width. Soy wax has a memory: a short first burn leaves a tunnel that it will follow every time.

2. Trim the wick

Trim to about 5 mm before each light. A long wick makes a tall, smoky flame and blackens the jar.

3. Burn in sessions of up to four hours

Longer burns can overheat the vessel and make the wick mushroom. Let the candle cool before relighting.

4. Keep it safe

Burn on a heat-proof surface, away from draughts, curtains, children and pets. Never leave a burning candle unattended.

5. Know when to stop

Stop when about 1 cm of wax remains. Then pop the jar in the freezer for a few hours, lift out the wax, wash with warm soapy water and reuse it.