How do I make candles at home?

Matching wick to container size, the pouring temperature that avoids sinkholes, and why the first burn decides how the candle behaves.

Difficulty: beginner
Time: 1 hr 30 min
Read: 4 min
Safety: warning

Short answer

Choose the wick from the container diameter and the wax type, melt the wax gently to the manufacturer's temperature, add fragrance off the heat at the stated temperature, and pour into a warmed container. Then leave it a week before burning.

Candle making is mostly temperature control and wick sizing. Almost every fault — tunnelling, sinkholes, poor scent, a smoking flame — traces back to one of those two rather than to technique.

Safety

Melt wax in a double boiler or a dedicated wax melter, never in a pan directly on the heat — wax above roughly 200°C can ignite. Never leave melting wax unattended and keep a pan lid or fire blanket to hand; a wax fire must be smothered, never doused with water, which spreads burning wax violently. Fragrance oils are flammable and go in only once the wax is off the heat and cooled to the stated temperature. Keep children and pets out of the room.

What you'll need

Soy, rapeseed or paraffin wax
Wicks sized for the container diameter
A thermometer
A double boiler or heatproof jug in a pan of water
Heatproof containers

Step by step

Choose the wax first.Soy and rapeseed are easier for containers and burn slower; paraffin holds fragrance more strongly and gives a better scent throw. Each has a different melt and pour temperature stated by the supplier.
Match the wick to the container diameter.Wick suppliers publish sizing charts by diameter and wax type. This is the single most important decision — everything else can be adjusted, and an undersized wick tunnels while an oversized one smokes.
Melt in a double boiler.A heatproof jug standing in a pan of simmering water. Never directly on a hob. Wax heated too far will catch fire, and it does so without much warning.
Use a thermometer.Every stage has a target temperature from the wax supplier — melt point, fragrance addition and pour temperature. Guessing produces most of the common defects.
Secure the wick before pouring.Wick sticker or a dab of hot glue at the base, and a peg or wick bar across the top to hold it central and upright. A wick that drifts off centre makes the candle burn unevenly for its whole life.
Add fragrance off the heat at the right temperature.Usually around 60 to 65°C for soy, but follow the wax supplier. Too hot and the fragrance burns off; too cool and it does not bind into the wax.
Stir gently for two minutes.Slow and thorough. Vigorous stirring whips air in, which shows as bubbles and rough patches. Under-stirring leaves fragrance pooled at the bottom, which is a fire risk.
Warm the containers before pouring.Gently, with a hairdryer or in a low oven. Pouring hot wax into a cold jar cools the outside too fast and causes the wax to pull away from the glass — the marks known as wet spots.
Pour slowly at the stated temperature.Steadily, in one go, leaving a little wax back for a top-up. Pouring too hot causes sinkholes around the wick; too cool causes a rough, lumpy surface.
Cool slowly and undisturbed.At room temperature, away from draughts, not in the fridge. Rapid cooling causes cracks and frosting.
Top up any sinkhole.Once set, poke the area round the wick with a skewer and pour a thin second layer slightly cooler than the first.
Cure before burning.One to two weeks for soy wax. The fragrance binds into the wax over that time, and a candle burned the next day smells weak.
Trim the wick and get the first burn right.Trim to about 5mm and burn until the melt pool reaches the edge of the container — usually one to two hours. Wax has a memory, and a short first burn sets a tunnel for good.

Tips

Wick size is chosen from container diameter and wax type. Get it from the supplier's chart.
The first burn must reach the edges. Wax remembers the first melt pool.
Cure soy candles for a week or two before burning or the scent will disappoint.

Common mistakes

Melting wax directly in a pan on the hob — Wax can exceed its flash point quickly and ignite, and a wax fire cannot be put out with water. A double boiler caps the temperature at roughly boiling point.
Adding fragrance to very hot wax — Fragrance oils are volatile. Added above the wax supplier's recommended temperature much of the scent evaporates immediately, and the finished candle smells of almost nothing.

If it doesn't work

Candle tunnels down the middle

Cause: Wick too small, or a short first burn — Fix: Size the wick up next time; for the current candle, burn until the pool reaches the edge each time.

Large flame, smoking and soot

Cause: Wick too large or untrimmed — Fix: Trim to 5mm before every burn and use a smaller wick in the next batch.

Sinkhole around the wick

Cause: Poured too hot, or cooled too fast — Fix: Poke and top up with a thin second pour at a slightly lower temperature.

Wax pulled away from the glass

Cause: Cold container or fast cooling — Fix: Warm the containers before pouring and cool slowly at room temperature. It is cosmetic only.

Almost no scent

Cause: Fragrance added too hot, too little used, or no cure time — Fix: Follow the supplier's fragrance load and temperature, and cure for one to two weeks.

Questions people ask

How much fragrance should I add?

Follow the wax supplier's maximum fragrance load, typically six to ten per cent by weight. Exceeding it does not make the candle smell stronger — the excess separates out and becomes a fire hazard.

Why does my candle smell strong cold but weak when lit?

Cold throw and hot throw are different properties. Weak hot throw usually means the wick is too small to melt enough wax, or the candle has not cured long enough.