Vivid Ready

Tallow candles are soft, smell of what they came from, and were what most of Britain burned for centuries. Making them well is a matter of hardening the fat and matching the wick. The oil lamp is easier and gives more light per unit of fat.

What you are actually making

Tallow candles lit Britain for centuries and nobody liked them. They were described at the time as smoky, unwholesome and expensive. Wax was for churches and the rich; tallow was for everyone else.

They are worth knowing how to make anyway, because the raw material is a byproduct you already have if you are rendering fat at all, it stores for years, and light after dark is one of the things that most affects whether a household functions or simply stops at four in the afternoon.

Start at rendering tallow and lard. That page is the prerequisite: this one assumes you have clean rendered fat already, and clean is the operative word. Fat with meat scraps or water left in it will smell, spit and go rancid.

The fat, and why the animal matters

Harder fat makes better candles, and hardness varies by animal more than people expect.

Source	Hardness	Verdict
Deer, goat	Hardest	Best available, if you have it
Beef	Hard	The standard. What tallow normally means
Sheep, mutton	Fairly hard	Good, strong smell
Pig (lard)	Soft	Poor alone. Lamps and blending only

Tallow melts at about 42 to 45°C. That is the root of every problem with it. Good commercial candle waxes melt at roughly 52 to 74°C, so tallow is well below the useful range: it softens in a warm room, sags in summer, and burns faster than it should because the melt pool spreads too readily.

Wet rendering, with water and salt, gives a cleaner and less smelly result than dry rendering, and for candles that difference is worth the extra hour. It is the method on the rendering page.

Hardening it

This is the single change that turns a poor tallow candle into a decent one.

Beeswax is the best addition. It melts at about 82°C, so even a modest proportion lifts the blend usefully.

Start at about 1 part beeswax to 3 parts tallow and adjust.
More beeswax gives a harder, slower, cleaner candle and costs you beeswax.
It also masks the smell. Beeswax carries a light honey scent that covers tallow's animal note, which is a real benefit and not a cosmetic one when the candle is burning in a room where people are eating.

Stearic acid is the traditional commercial hardener and works well if you happen to have it. Alum was the old improvised answer: dissolve it in the melted fat. Both raise the melting point and reduce guttering.

A candle that guttes, sags or drowns its own wick is almost always too soft. Harden the blend before you start blaming the wick.

Wicks

Tallow needs a thicker wick than wax does at the same diameter. This follows from the low melting point: the melt pool forms readily, so the wick must be able to draw and burn that fuel or it drowns.

Too thin and it tunnels, burning a hole down the middle while the outside stays solid, or it drowns in its own melt.
Too thick and it smokes, burns fast, and gives a large unsteady flame.
Braided cotton is what you want. Butcher's string, cotton twine, or a strip of cotton sheet twisted tight. Not synthetic, which melts and stinks.
Prime the wick. Soak it in melted fat and let it cool straight before use. A primed wick lights first time and burns steadily from the start.
Test before you commit. Make one candle, burn it for an hour, and look at the melt pool. A good candle melts to the edge without pooling over. Then make forty.

Trim to about 6 mm before every burn. An untrimmed wick is the main cause of both smoke and smell, and it is the single most common reason people conclude tallow candles are unpleasant when in fact theirs simply needed a trim.

Dipping

The traditional method, no mould required, and much easier with several at once.

Melt the fat to a little above its melting point. Not hot. Overheating darkens it and makes it smell.
Cut wicks to twice the candle length plus a hand's width, so you can dip two candles on one wick over a stick.
Dip, lift, let it cool until it is set but not cold. A few seconds.
Dip again. Each pass adds a thin layer.
Repeat 20 to 40 times depending on the thickness you want.
Hang to cure for a day, then trim the base flat.

The temperature has to stay in a narrow band. Too hot and each dip melts off the previous layer, so the candle never grows. Too cool and it goes on lumpy. A rack of dipping frames and a second person makes this quick; alone it is slow work, which is exactly why the moulds below were invented.

Dip in cold weather if you can. The cooling between dips is the rate-limiting step and a cold day halves the work.

Moulding and container candles

Moulds are faster and give a neater candle.

Anything smooth and tapered that lets the candle out. Metal tubing, cardboard tubes, silicone, or a purpose-made mould.
Wick down the centre, held taut with a stick or pencil across the top and knotted or plugged at the base.
Pour just above melting point, not hot.
Expect a dip in the middle as it cools and shrinks. Top it up with a second pour once set.
Chill to release. Cold makes the candle contract away from the mould.

Container candles are the easier answer for tallow specifically, and they suit its softness rather than fighting it. Pour into a jar, tin or cup with a wick held central. Nothing to release, nothing to sag, and if it softens in a warm room it does not matter because the container holds it. For a household that simply wants light, container candles in jam jars are the sensible production run.

The fat lamp, which is easier and better

If you want light rather than candles, make a lamp. It is quicker, wastes less, gives a steadier flame, and can burn fat too soft for a candle.

The simplest version:

A shallow non-flammable dish. Pottery, a tin, a stone hollow, a shell.
Melted fat, or oil, filling it.
A wick lying in the fat with one end raised at the rim, or held up on a twist of wire or a pebble. Only a few millimetres should stand proud.
Light the raised end.

The flame melts the fat around the wick, capillary action draws it up, and it burns. This is the oldest lamp design there is and it works with anything from tallow to cooking oil to the fat skimmed off a stew.

Improvements worth making:

A wire wick holder keeps the height right and stops the wick sliding in.
A lid with a spout, so it cannot spill and dust cannot get in.
A shallow, wide dish gives a bigger flame; a narrow one gives a smaller, longer-lasting flame.
Any liquid fat works. Olive oil burns notably clean. Used cooking oil works and smells of what it cooked.

A float wick turns a jar of oil into a lamp: a small disc of cork or wood with a wick through the middle, floating on the surface. Elegant, safe, and it goes out on its own if tipped, which is more than can be said for most improvised lamps.

Burning any of it safely

DANGER

Open flame is the most likely thing to burn your house down in this scenario, and it will happen on the night everyone is tired.

Candles cause a large share of house fires in ordinary times, when they are a decoration used occasionally. In a household lighting every room by flame every evening, for weeks, the exposure is completely different.

The rules, which are not negotiable because there is no fire brigade in this scenario:

Never leave a flame in an empty room. Ever, not for a minute.
Never leave one burning while anyone sleeps.
On a stable, non-flammable surface, well away from curtains, bedding, paper and anything that can fall.
In a holder that cannot tip. A candle stuck to a saucer with its own wax is not a holder.
Well clear of anything above it. A shelf a foot above a candle chars, then ignites.
Out of reach of children and animals. A cat's tail through a flame ends with a burning cat in the house.
A snuffer, not blown out. Blowing scatters hot wax and can throw sparks from a long wick.

One working torch beats a room full of candles for safety, every time. Use flame for ambient light and long evenings, and keep a torch for moving around, going upstairs and anything involving your hands.

Have a fire blanket and a means to put out a fire in every room where you burn things. A bucket of sand or water, or a blanket.
Watch for CO. Any flame consumes oxygen and produces carbon monoxide when it burns imperfectly. Several candles or lamps in a small closed room is a real exposure, not a theoretical one. See ventilating indoor burning, and note that a smoky flame is an incompletely burning flame.
Ventilate. A small opening is enough and it costs less heat than people fear.

How much light this actually gives

Worth being honest about, because expectations set from film and television are wrong.

A single candle is roughly one candela, which is very little. It is enough to see the room's shape, to find a door, to sit and talk. It is not enough to read comfortably, sew, or do anything precise. A single LED torch on its lowest setting outperforms several candles for usable light and costs a tiny fraction of the fuel.

What this means for planning:

Cluster the light and cluster the people. One well-lit table where everyone gathers is worth far more than six dim rooms, and it saves fat, heat and attention.
A reflector doubles the useful output. Anything white or shiny behind the flame: a tin lid, foil, a white plate, a mirror.
Put light where hands work, not on the ceiling.
Save the electric light for tasks. Rechargeable lighting from the 12V system is for reading, first aid and anything with a needle or a blade. Flame is for atmosphere and for when the batteries are gone.

Store more candles than you think you need. They keep essentially forever, take almost no space, and burning time disappears far faster than anyone estimates: a household lighting one room for four hours a night gets through a great deal in a winter.