Quick Answer: Most soy candle problems come down to three things: wrong wick size, wrong pouring temperature, or not enough cure time. If your candle tunnels, size up the wick. If it frosts, pour cooler. If the scent is weak, wait 1-2 weeks before testing.
Tunneling
Tunneling is when the candle burns straight down the middle, leaving a thick wall of unmelted wax around the edges. It’s the most common candle problem and the most frustrating.
Causes
- Wick too small — the flame doesn’t produce enough heat to melt wax to the jar walls (most common cause)
- First burn too short — soy wax has “memory.” If the first burn doesn’t create a full melt pool, subsequent burns follow the same tunnel
- Jar too wide — single-wick candles over 3.5 inches in diameter often need double wicks
Fixes
Prevention (before lighting):
- Use a larger wick size. Consult your supplier’s wick guide — for Golden 464 in a 3-inch jar, most makers start with CD or ECO series
- Check our wick size guide for starting recommendations
First burn rule:
- Burn your candle until the melt pool reaches the edges on the very first burn
- This usually takes 1 hour per inch of jar diameter (a 3-inch jar needs ~3 hours)
- Don’t blow it out early
Rescue (if already tunneling):
- Wrap the jar in aluminum foil, leaving the top open
- Light the candle — the foil reflects heat and helps melt the wall wax
- After a full melt pool forms, remove the foil
- Alternatively, use a heat gun to melt the top layer flat
Frosting
Frosting appears as white, crystalline patches on the surface or sides of soy candles. It’s caused by polymorphism — the soy wax forming different crystal structures as it cools.
Important truth
Frosting is unavoidable in 100% soy wax. You can minimize it, but you can’t eliminate it entirely. It’s a natural characteristic, not a defect. It doesn’t affect burn quality or scent throw.
Minimizing frosting
- Pour temperature: Lower is better. Try 125-135F (51-57C) for Golden 464
- Warm your jars: Heat jars to about 100-120F before pouring
- Cool slowly: Don’t put candles near windows, AC vents, or fans
- Avoid temperature swings: Cool candles in a room at consistent 70-75F
- Dye helps: Candles with dye tend to frost less than uncolored ones
Marketing approach
Many successful soy candle brands lean into frosting as proof of natural soy wax. “Frosting is a sign of pure soy” is both true and effective marketing.
Wet Spots
Wet spots are patches where the wax has pulled away from the glass, creating visible air gaps. They look like the wax is “wet” in spots, but it’s actually a lack of adhesion.
Causes
- Temperature changes during or after cooling
- Pouring too hot or too cold
- Jar surface not clean or warm enough
- Natural shrinkage as wax cools
Fixes
- Preheat jars to 100-120F
- Pour at the right temperature — 130-140F for most soy waxes
- Clean jars thoroughly — any residue or moisture prevents adhesion
- Cool slowly and evenly — cover candles with a box or towel while setting
- Consider a heat gun — briefly warming the outside of the jar after the candle sets can help wax re-adhere
Wet spots are cosmetic only. They don’t affect burn performance.
Sinkholes
Sinkholes are depressions or cavities that form around the wick as the candle cools. The surface might look fine, but there’s a void underneath.
Why they happen
As wax cools, it contracts. The outer edges cool first and lock in place, but the inner wax continues to shrink, pulling away from the wick and creating hollow spaces.
Prevention
- Poke relief holes — after the surface has set but the wax is still warm underneath (about 1-2 hours), poke 2-3 holes around the wick with a chopstick
- Second pour — melt more wax and top off the candle to fill voids
- Pour cooler — lower pour temperature = less contraction
- Don’t move candles while they’re setting
Fix for finished candles
Use a heat gun to melt the surface, let air escape, and allow it to resettle flat. You may need to add a small amount of wax to fill the depression.
Poor Scent Throw
Scent throw has two components: cold throw (scent when unlit) and hot throw (scent while burning). If either is weak, here’s what to check.
Weak cold throw
- Fragrance percentage too low — try 8-10% for soy. Use our calculator to get exact measurements
- Not enough cure time — soy wax needs 1-2 weeks. The wax and fragrance molecules need time to bind properly
- Fragrance quality — cheap fragrance oils often have weak cold throw. CandleScience and Lone Star rate their oils for soy performance
Weak hot throw
- Wick too small — a small flame creates a shallow melt pool that doesn’t release fragrance effectively
- Not enough cure time — same as cold throw
- Added fragrance at wrong temperature — too hot (above 200F) and fragrance evaporates. Too cool (below 170F) and it doesn’t bind. Aim for 180-185F for most soy waxes
- Room too large — a 4 oz candle can’t fill a living room. Match candle size to room size
The cure time myth and reality
You’ll hear “soy needs 2 weeks to cure.” This is real but often exaggerated. Most soy candles show noticeable scent improvement between day 3 and day 10. After 2 weeks, changes are minimal. Test at 3 days, 7 days, and 14 days to understand your specific wax-fragrance combination.
Mushrooming
Mushrooming is when the wick tip forms a carbon ball that looks like a mushroom cap. Small mushrooms are normal, but large ones indicate a problem.
Causes
- Wick too large for the container
- Fragrance load too high
- Low-quality wick (inconsistent braid)
Fix
- Trim the wick to 1/4 inch before every burn
- Try one wick size smaller
- If you’re above 10% fragrance, try reducing it
Smoking and Soot
A properly made soy candle should produce minimal soot. If yours is smoking:
Check these first
- Wick too long — trim to 1/4 inch. This is the #1 cause
- Wick too large — the flame is too big, consuming wax faster than it can vaporize
- Drafts — air movement causes the flame to flicker and produce soot
- Fragrance oil flash point — very low flash point oils can cause smoking. Check the SDS
Prevention
- Always trim wicks before lighting
- Keep candles away from vents, fans, and open windows
- Don’t burn for more than 4 hours at a time
- Follow safe candle burning practices (NCA guidelines)
Cracking
Surface cracks usually appear during cooling. They’re caused by the wax cooling too quickly or unevenly.
Fixes
- Cool candles at room temperature, away from cold surfaces
- Don’t refrigerate candles to speed cooling
- Pour at a slightly lower temperature
- Cover candles during cooling to insulate them
Quick Troubleshooting Checklist
| Problem | Most likely cause | First thing to try |
|---|---|---|
| Tunneling | Wick too small | Size up one wick |
| Frosting | Natural soy property | Pour cooler, accept it |
| Wet spots | Temperature change | Preheat jars |
| Sinkholes | Wax contraction | Poke holes + second pour |
| Weak scent | Low fragrance or no cure | 8-10% fragrance, wait 2 weeks |
| Mushrooming | Wick too big | Size down one wick |
| Smoking | Wick too long | Trim to 1/4 inch |
| Cracking | Cooled too fast | Cool at room temp |
Still not sure how much wax or fragrance you need? Use our calculator to get the right measurements before you pour.
FAQ
Why is my soy candle tunneling?
Tunneling is almost always caused by a wick that’s too small. The flame can’t generate enough heat to melt wax to the edges. Try sizing up one wick size. Also, always let the first burn create a full melt pool.
How do I fix frosting on soy candles?
You can’t completely prevent frosting in soy wax — it’s a natural characteristic. To minimize it, pour at a lower temperature (125-135F), warm your jars before pouring, and cool candles slowly away from drafts.
Why does my candle have no scent when burning?
Poor hot throw usually means your fragrance percentage is too low, the wick is too small (not enough melt pool), or the candle hasn’t cured long enough. Soy candles need 1-2 weeks of cure time for full scent.
Can I fix a candle that has sinkholes?
Yes. Heat the surface with a heat gun until it melts, then let it cool slowly. For prevention, poke relief holes around the wick after the candle is partially set, then top with more wax.