Tunneling is the candle's saddest flaw — a hole down the middle and a wall of wasted wax. Here's how to avoid it.

The first burn is everything

On the first light, let the wax melt all the way to the glass edge before you blow it out. That sets the memory of the wax, and it never tunnels after.

Trim the wick

A wick longer than a quarter inch burns too hot and smokes. Trim it every time, and the melt stays even for the whole jar.