Why taper candles drip, and how to stop it

A taper candle that drips is not usually a defective candle. It is a candle in moving air. The whole design of a taper depends on the flame melting wax at roughly the rate the wick can drink it, and that balance is easy to upset. Here is what actually causes the drip, in the order worth checking, and what non drip means on a label.

How a taper is supposed to work

A taper burns by melting a shallow pool of wax in the hollow at the top, drawing it up the wick and burning it as vapour. The pool is tiny, a few millimetres deep, and the rim of unmelted wax around it is the only thing keeping it there. Burn the candle in still air and the rim stays even, nothing escapes, and the candle consumes itself as it goes.

The drip starts when the rim fails on one side. Molten wax then has nowhere to go but over the edge, so it runs down the cold shaft, sets, and now there is a channel for the next lot to follow. Once a candle has started dripping it keeps dripping, because the channel is a permanent feature of the candle.

So the question is never really why wax is running down the side. It is why the rim broke.

Draughts, which is the answer about four times in five

A flame in still air is a vertical teardrop and its heat goes straight up. Tilt it with the gentlest sideways current and the heat goes into the rim on one side instead. That side melts faster and lower, and the pool spills. You do not need to be able to feel the draught: if the flame is visibly moving, the air is moving enough.

The usual sources are not the obvious ones. A doorway onto a hall, a stairwell, a chimney breast, which draws air even with no fire in it, an open internal door making a cross current between two rooms, forced air heating, a ceiling fan on its lowest setting, a cold window pane with air rolling down the glass, and people walking past. A mantelpiece is the draughtiest place in most rooms and it is where everybody puts candles.

Move the candle half a metre and watch what happens before you go and buy different candles. That is a free experiment and it works more often than it has any right to.

What non drip actually means

Non drip is a formulation and a wick, not a coating. Harder wax with a higher melting point gives a stronger rim that resists breaking down on one side. A wick sized tightly to that wax keeps the flame small enough that the melt rate never outruns the rate the wick can draw. That is the whole of it.

Beeswax tapers tend to be the hardest and are often the least likely to drip. Paraffin dipped tapers vary enormously with the blend. Soft waxes drip more. None of them are non drip in a draught, and a label promising otherwise is describing a candle in a sealed room.

Thickness helps too. A thicker taper has a wider rim and more cold wax around the pool to hold it, so it tolerates slightly more air movement than a thin one does.

Wick length, the second most common cause

Trim the wick to about five millimetres before every light. A long wick makes a tall, fat flame, and a big flame melts a wider and deeper pool than the wick can keep up with. The surplus wax has to go somewhere, and over the rim is where it goes.

A long wick also curls over, grows a ball of carbon on the end and starts sooting. If the flame is much taller than about twenty five millimetres, or you can see smoke coming off a candle standing in still air, it needs trimming. Snuff it, let it set for a minute, trim, relight.

Trim the wick and not the candle. Nail scissors are perfectly adequate, and the trimmings should come out of the wax rather than being left in it.

Make it stand straight

A leaning taper always drips, because the rim starts out lower on one side. Most leaning comes from a taper that is slightly too narrow for the socket, which is extremely common, since neither tapers nor holders are made to any agreed diameter.

The fix is not a knife. Stand the base of the candle in hot water for five to ten seconds to soften it, press it into the socket and let it cool, and it will take the shape of the socket. For a hole that is far too big, candle fixing putty or a wax collar does the job. Carving a cold taper with a blade snaps it as often as it works.

Then check the holder is level and the surface under the holder is level too. Neither is a given on an old mantel or a painted shelf. A heavy cast holder, something on the scale of the black cat candlesticks, is at least harder to knock askew than a light one.

Match the candle to the holder, and know when to stop

A taper needs a socket. A pillar needs a flat dish, ideally with a lip. The two are not interchangeable: a taper wedged into a pillar dish will lean, and a pillar balanced on a taper socket is a fire waiting for an excuse. The iron scroll sconce takes pillars rather than tapers, and so do the cat candlesticks, despite what the name suggests.

Our two taper socketed holders, the stone skull and the owl, are not available at the moment. If you are shopping for a taper holder anywhere, the thing to look at is the depth of the socket. A shallow socket will not hold a long candle upright for long, whatever it looks like in the photograph.

Stop burning a taper while there is still a decent amount of it left, at least fifty millimetres above the holder. The last part of a taper burns close to the metal or the stone, heats the holder up, and that is where wax runs out fastest and where scorching happens.

Questions people actually ask

Why do my candles drip down one side only?

Because heat is reaching one side of the rim more than the other, almost always from a draught tilting the flame. A candle leaning in its holder does the same thing, so check it is sitting straight as well as checking the room.

Are non drip candles actually non drip?

Only in still air. Non drip describes a harder wax and a wick matched to it, which makes the rim more robust. Put the same candle in a draught and it will drip like any other candle.

How long should a candle wick be?

About five millimetres, trimmed before each burn. Any longer gives a tall flame that melts more wax than the wick can draw up, and the surplus is what overflows and runs down the side.