At Concrete Kreation, we work closely with candle brands across India, the UAE, the UK, and beyond — supplying the concrete candle vessels that hold their craft. Over the years, we've heard it all: tunnelling, sinkholes, frosting, sweating, adhesion failures. These aren't signs of a bad candle maker — they're common, fixable problems that even experienced brands run into.
This guide covers the 10 most frequent candle making problems, why they happen, and the precise fixes that actually work.
01 - Tunnelling — Candle Burns Down the Middle
Tunnelling is one of the most frustrating problems for candle makers. The wick burns straight down through the centre, leaving a thick wall of unmelted wax around the edges. Not only does it look unfinished — it wastes product and disappoints your customer.
Why it happens: Undersized wick, wax with a very high melting point, or the candle not receiving a long enough first burn (the "memory burn").
THE FIXAlways size your wick up for the diameter of your vessel. Instruct customers to burn the candle until the melt pool reaches the edges on the very first use — typically 1 hour per inch of diameter. Also consider a wax blend with a slightly lower melt point for wider jars.
02 - Sinkholes & Sunken Tops After Pouring
You pour a beautiful candle, let it cool, and wake up to a crater in the middle of the surface. Sinkholes form as wax contracts during cooling, pulling away from the centre faster than the outer edges.
Why it happens: Wax cools too quickly, pour temperature too high, or pouring in a cold room with no temperature control.
THE FIXPour at a slightly lower temperature (around 5–10°C below your wax's recommended pour point). Do a second "top-up" pour once the candle has set halfway. Let candles cool at room temperature — avoid placing them in refrigerators or near air conditioning vents.
03 - Frosting — White, Powdery Surface Bloom
Frosting shows up as a white, dusty coating or crystalline bloom on the surface and sides of soy candles. It's purely aesthetic and harmless, but it looks like something went wrong — which matters enormously to retail and gifting customers.
Why it happens: Frosting is a natural property of pure soy wax as it crystallises over time. Rapid temperature change accelerates it significantly.
THE FIXUse a soy-paraffin blend or a soy wax specifically formulated to reduce frosting. Control your environment — pour in a warm room and cool candles slowly and evenly. Adding UV inhibitors to your wax can also slow down the process and extend shelf life appearance.
04 - Candle Won't Throw Scent (Weak Hot Throw)
Your candle smells incredible cold — but the moment it's lit, the fragrance barely fills the room. Scent throw is one of the most common complaints candle customers raise, and it directly impacts repeat purchase rates.
Why it happens: Fragrance load is too low, wax type doesn't bind well with the fragrance oil, or the wick isn't producing a large enough melt pool.
THE FIXIncrease your fragrance load up to your wax's maximum binding capacity (typically 6–12% by weight). Add fragrance at the right temperature — usually around 65–70°C — to ensure proper binding. Re-evaluate your wick size: a larger melt pool disperses more scent. Also test your fragrance oils with that specific wax — not all pairings perform equally.
05 - Wick Mushrooming & Excessive Soot
If your wick develops a large, carbon "mushroom" cap at the tip and leaves black soot marks on the vessel walls or around the candle, it signals an imbalance between the wick and the fuel being delivered to it.
Why it happens: Wick is too large for the vessel diameter, fragrance load is too high, or the fragrance oil contains components that don't combust cleanly.
THE FIXSize your wick down. Trim the wick to 5–6mm before every burn — and put this instruction on your label. Audit your fragrance oil; some synthetic compounds are known soot producers. If switching fragrances isn't an option, try a cotton-core wick series known for clean burn performance.
06 - Wax Not Adhering to the Vessel Walls
Wet spots — where the wax pulls away from the container — are extremely common in glass and concrete candle vessels. They create an uneven, blotchy look through the side of the jar that makes the candle look defective even when it performs perfectly.
Why it happens: Thermal contraction of the wax as it cools, combined with the vessel surface. More common in winter or when pouring into cold containers.
THE FIXWarm your vessels before pouring — place them in a warm oven (around 40–50°C) for a few minutes. Pour at a slightly higher temperature for container candles. If using glass, a soy-paraffin blend adheres better than 100% soy. For concrete vessels like ours, this is less of an issue — the matte, porous interior naturally helps wax bond.
07 - Candle "Sweating" — Oily Beads on the Surface
You notice tiny oil droplets or a greasy sheen forming on the top of your cooled candles. This is called sweating — and it's a sign that the fragrance oil has separated from the wax blend.
Why it happens: Fragrance load exceeds the wax's saturation point, temperature fluctuations in storage, or using fragrance oils with a very low flash point.
THE FIXReduce your fragrance percentage and ensure you're not exceeding the wax's maximum load. Store finished candles at a stable temperature away from direct sunlight. Check that your fragrance oils are specifically formulated for the wax type you're using — coconut wax, for example, has different absorption characteristics than paraffin.
08 - Uneven or Rough Surface After Cooling
Instead of a smooth, flat top, your candle sets with a bumpy, rough, or cratered surface that looks unprofessional and is hard to photograph for your brand.
Why it happens: Air bubbles trapped during pouring, cooling too fast, or stirring the fragrance in too vigorously and introducing air.
THE FIXStir fragrance in slowly and steadily — do not whip or overmix. Pour slowly and steadily in a thin stream. Use a heat gun to lightly sweep over the surface once the candle has begun to set; this levels out imperfections without melting the whole top. Pour a thin "finish coat" for a perfectly flat top layer if aesthetics are critical for retail presentation.
09 - Wick Keeps Moving or Falling Over
You centre your wick perfectly, begin the pour — and by the time the wax sets, the wick has shifted to the side or sunk completely. A off-centre wick leads to uneven burning and tunnelling.
Why it happens: Wick isn't properly anchored at the base, pour is too fast and disturbs the wick, or the wick bar/holder is inadequate for the vessel diameter.
THE FIXAlways use a wick sticker or hot glue to anchor the tab firmly to the base of the vessel before pouring. Use a proper wick centering tool — our stainless steel auto wick centring tool holds the wick in perfect position across multiple candles simultaneously, eliminating human error entirely during high-volume wholesale candle production runs.
10 - Colour Fading or Dye Migration Over Time
You pour a rich, vivid coloured candle — and within weeks, the colour fades, bleeds into the wax, or migrates unevenly through the vessel wall. This is especially damaging for gifting collections where visual presentation is everything.
Why it happens: Using candle dyes incompatible with the wax type, exposure to UV light, or dye ratios that are too high causing over-saturation.
THE FIXAlways use dyes specifically rated for your wax type — liquid dyes disperse better in paraffin, while blocks or chips often suit soy better. Add UV inhibitors to your wax if candles will be displayed near windows or in bright retail environments. Store candles away from direct light. Test batch-to-batch dye consistency carefully; natural wax colour variations affect the final shade.
The Right Vessel Makes
All the Difference
Solving these problems starts before the first pour. A quality concrete candle jar — one that holds temperature evenly, bonds well with wax, and photographs beautifully — gives your candle the best possible start.
