Tunneling
A tunnel is a well down the middle of the candle with a wall of untouched wax around it. It usually starts when the first burn ends before the pool reaches the edge. The deeper the tunnel gets, the harder it is to fix, and the wall can eventually smother the flame.
Tunneling
Short burns left a well down the middle and a wall of hard wax around it. The wall wastes wax and can drown the wick.
Full melt pool
A shallow pool runs edge to edge. This is the shape to aim for on the first burn and on every burn after it.
To fix a shallow tunnel, burn the candle for a longer session so the pool can catch up with the walls. For a deeper one, a common method is to wrap a collar of aluminum foil around the top of the jar, leaving an opening over the flame. The foil reflects heat onto the wall of wax and helps it melt. Stay with the candle the whole time, remove the foil with oven mitts once the surface is level, and don't use this method on a candle that is already very hot.
Black smoke and soot
Dark smoke, black marks on the glass, and a tall, flickering flame all point to the same cause: the flame is getting more fuel than it can burn cleanly. Check these in order:
- Wick length. Trim it to about 1/4 inch once the candle is cool.
- Drafts. Moving air from fans, vents, open windows or people walking past makes the flame flicker and smoke.
- Burn time. Long sessions build carbon on the wick. Stop after about four hours.
- Wick size. If a trimmed wick in still air still flares, the candle may have too large a wick for its jar.
Clean soot from a cool jar with a dry paper towel or a cloth before the next burn.
Drowning wick
A small flame that shrinks and goes out in a deep pool means the wick can't keep up. It may be trimmed too short, or the wick may be too small for the wax. Put the candle out, let it harden, then scrape away a little wax around the wick so more of it shows, and light it again. If it keeps happening, the wick is undersized.
Drowning wick
A tiny flame sits low in a deep pool. Put it out, let the wax harden, then scrape a little wax away from the wick.
Trimmed wick
About 1/4 inch of wick gives a steady, teardrop flame with little or no smoke.
A flame that dances or pops
Flickering is almost always a draft. Pops and sputters can mean water got into the wax, a bit of debris is in the pool, or there are air pockets around the wick. Remove anything floating in the wax once it has cooled. Wood wicks crackle by design, so a soft crackle from a wood wick is normal.
Frosting, wet spots and a sunken top
Plant waxes, soy in particular, often grow a white crystal bloom called frosting. Areas where the wax has pulled away from the glass, called wet spots, look like damp patches. A rough or sunken top can appear after a burn as the wax cools. These are cosmetic. They don't change how the candle burns, and the next burn usually smooths the top again.
A candle that has lost its scent
A scented candle that seemed strong in the store can feel faint at home. A large or drafty room spreads the scent thin, and our noses get used to a smell within a short time. Try the candle in a smaller room, let it build a full melt pool, and step out of the room and back in. Candles left uncovered for months can also lose some fragrance; keep lids on during storage.
Stop and put it out if the flame is very large, the jar is cracked, the container is too hot to touch near the top, or the flame is touching the side of the glass. A candle doing any of these is no longer safe to keep burning.