Getting the wick right is arguably the most important part of candle making. The wrong wick can cause tunnelling, mushrooming, poor scent throw, excessive soot, or an unsafe burn. The right wick gives you an even melt pool, clean burn, and strong fragrance release every time.
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This guide explains how candle wicks work, the different types available, and — most importantly — how to choose the correct size for your container. If you’re brand new to candle making, read our complete beginner’s guide first for the full picture.
How Candle Wicks Work
A candle wick draws melted wax up through capillary action, like a straw. The wax vapourises in the flame, which is what actually burns — the wick itself is just the delivery system. The size and construction of the wick determines how much wax is drawn up, which controls the flame size, the melt pool diameter, and the burn rate.
If the wick is too small, it can’t draw enough wax to melt all the way to the container edges. This causes tunnelling — the candle burns down the centre, wasting wax and reducing scent throw. If the wick is too large, the flame is oversized, the candle burns through too quickly, and you’ll get soot, mushrooming, and potentially an overheated container.
Types of Candle Wicks
The UK candle making community primarily uses these wick types:
CD (Stabilo) wicks are flat braided cotton wicks with a paper filament woven in. The paper thread helps the wick curl as it burns, which keeps it self-trimming. CD wicks are excellent for soy wax and coconut-rapeseed blends. They’re the most popular choice for UK candle makers working with natural waxes.
ECO wicks are flat cotton wicks with a thin paper core. They burn slightly cooler than CD wicks and are a good choice if you find CD wicks burn too aggressively in your containers. They work well with soy and soy-blend waxes.
LX wicks are braided cotton with a stabilising thread. They’re designed for paraffin but also work with soy. LX wicks tend to produce a stable, consistent flame.
Wooden wicks are a popular aesthetic choice — they produce a gentle crackling sound reminiscent of a fireplace. They look beautiful in container candles but require more testing to get the sizing right, as they behave quite differently from cotton wicks.
Pre-waxed cotton wicks with sustainers are what most beginners use. These come ready to go — the wick is coated in wax and attached to a small metal tab (sustainer) that sits at the bottom of your container. They’re the easiest option and what we recommend for your first candles.
How to Choose the Right Wick Size
Wick sizing depends primarily on your container diameter. The goal is to achieve a full melt pool — where the melted wax reaches all the way to the edges of the container — within about 2–3 hours of burning.
Here’s a general sizing guide for CD wicks with soy wax (the most common combination for UK makers):
For containers with a 50–60mm diameter (tealight to small votive): try a CD 4 or CD 5. For 60–70mm diameter (standard small jar): try a CD 6 or CD 8. For 70–80mm diameter (medium jar): try a CD 10 or CD 12. For 80–90mm diameter (large jar): try a CD 14 or CD 16. For containers over 90mm: you may need a CD 18 or CD 20, or consider using two wicks.
These are starting points, not guarantees. The actual performance depends on your specific wax, fragrance oil, dye, container shape, and room temperature. This is why testing is essential.
Testing Your Wicks
Professional candle makers always test multiple wick sizes before committing to a final recipe. Here’s how:
Make three identical candles using the same wax, fragrance, container, and technique — but use three different wick sizes. Choose the size you think is correct based on the guide above, then one size up and one size down.
Burn each candle for 4 hours at a time (matching the recommended burn cycle for container candles). Note the melt pool diameter after 2 hours and after 4 hours. Check for mushrooming, soot, and flame height. Repeat over multiple burn sessions until the candle is used up or you’ve gathered enough data.
The correct wick should achieve a full melt pool (edge to edge) within 2–3 hours, maintain a steady flame height of about 2–3cm, produce minimal soot, and not mushroom excessively.
Common Wick Problems and What They Mean
Tunnelling (wax only melts in the centre): wick is too small. Size up. See our detailed tunnelling fix guide.
Mushrooming (carbon ball on the wick tip): wick is slightly too large, or the candle has been burning too long without trimming. Try sizing down or trimming the wick to 5mm before each burn. Read more in our mushrooming guide.
Excessive soot (black smoke or residue on the jar): wick is too large, or there’s a draft disturbing the flame. Size down and burn in a draft-free area.
Weak scent throw: if the melt pool isn’t reaching the edges, the wick is too small. A full melt pool is essential for releasing fragrance. If you’re not getting enough scent despite a full melt pool, the issue is likely with your fragrance oil or cure time rather than the wick. Check our guide on fixing poor scent throw.
Flame too high or flickering: wick is too large, or it needs trimming. Always trim to 5–6mm before lighting. If the flame is still too high after trimming, size down.
Where to Buy Wicks in the UK
Pre-waxed cotton wicks with sustainers are widely available on Amazon UK and are the most convenient option for beginners. Browse our wicks section for our recommended options, or check out our beginner’s guide for a full supply list.
