Wick & Weigh

No. 12 · Fix

Candle Troubleshooter

Tap the problem you are seeing. Each card lists the usual causes, the fixes to try first, and which calculator helps.

Hands holding a lit jar candle
Photo: Rebecca Peterson-Hall on Unsplash
TunnelingThe candle burns a hole down the middle and leaves a wall of wax.

Usual causes

  • Wick too small for the jar
  • First burn too short to reach the edge
  • Fragrance or dye that needs a bigger wick

Try, in this order

  1. Test one or two wick sizes up
  2. Burn new candles long enough on the first light for the pool to reach the edge (about an hour per inch of width is a common guide)
  3. Recheck the wick after changing fragrance or dye

Open the wick test planner →

Soot, tall or flickering flameBlack marks on the glass, a large or dancing flame, a hot jar.

Usual causes

  • Wick too big
  • Wick not trimmed
  • Fragrance load too high or a heavy oil
  • Drafts

Try, in this order

  1. Test a size down
  2. Trim to about 1/4 inch before each burn
  3. Lower the load or check it against the wax maximum
  4. Burn away from vents and fans

Open the wick test planner →

Mushrooming wickA carbon ball forms on the tip of the wick.

Usual causes

  • Wick slightly large
  • Some fragrance and dye combinations
  • Long burns without trimming

Try, in this order

  1. Trim before each burn
  2. Try a size down or a different wick series
  3. Reduce dye

Open the wick test planner →

Wet spotsPatches where the wax has pulled away from the glass and looks wet.

Cosmetic: it does not change how the candle burns.

Usual causes

  • Wax shrinking from the glass as it cools
  • Cold or dirty jars
  • Cooling too fast

Try, in this order

  1. Warm jars before pouring
  2. Clean jars well
  3. Cool slowly, away from drafts
  4. Accept some: they do not affect the burn
FrostingWhite, crystal-like bloom on the top or sides, mostly in soy.

Cosmetic: it does not change how the candle burns.

Usual causes

  • Natural crystal growth in soy wax
  • Pouring too hot
  • Temperature swings in storage

Try, in this order

  1. Pour at your wax’s recommended temperature
  2. Store at a steady room temperature
  3. Choose a blend with additives if frosting matters for your look

Open the candle wax specs compared →

Sinkholes and cracksHoles or cracks near the wick, often hidden under the surface.

Usual causes

  • Wax shrinking as it cools
  • Pouring too hot
  • Cooling too fast

Try, in this order

  1. Pour cooler, within the wax’s range
  2. Poke relief holes and top up with a second pour
  3. Heat-gun the top to smooth it

Open the pillar and mold calculator →

Sweating or oily surfaceBeads of oil on top of the candle or melt.

Usual causes

  • Fragrance load above what the wax holds
  • Oil added too cool
  • Not stirred long enough
  • Warm storage

Try, in this order

  1. Check the load against the wax maximum
  2. Add oil at the supplier’s add-oil temperature
  3. Stir gently for about two minutes
  4. Store cool

Open the fragrance load calculator →

Weak scentYou smell it cold, but not much when it burns.

Usual causes

  • Not cured long enough
  • Wick too small to make a full pool
  • Oil added too cool
  • A light oil

Try, in this order

  1. Cure longer (soy often needs 1–2 weeks)
  2. Test a wick size up
  3. Add oil at the right temperature
  4. Try a higher load within the wax limit

Open the fragrance load calculator →

Rough or bumpy topsLumpy, cratered or uneven surface after setting.

Usual causes

  • Pouring too cool
  • Uneven cooling
  • The wax itself (some soy is like this)

Try, in this order

  1. Pour slightly warmer
  2. Cool at steady room temperature
  3. Smooth with a heat gun or a thin second pour
Jump linesRings or lines on the side of the candle.

Cosmetic: it does not change how the candle burns.

Usual causes

  • Pouring too cool
  • Pouring in stages
  • Cold jars

Try, in this order

  1. Pour warmer, in one smooth pour
  2. Warm the jars
Color changing over timeWax yellows or tans weeks after pouring.

Usual causes

  • Vanillin in the fragrance oil
  • Sunlight
  • Some dyes fading

Try, in this order

  1. Use vanillin-free oils for white candles
  2. Keep stock out of sunlight
  3. Add a UV inhibitor if your supplier sells one

Open the candle dye calculator →

Ran out of wax mid-pourThe last jars are short or empty.

Usual causes

  • Jar size taken from the listing, not weighed
  • No extra for the pitcher
  • Fragrance not counted in the batch

Try, in this order

  1. Weigh water in one jar and use the 0.86 factor
  2. Add 5–10% extra
  3. Plan by fill weight in the pour day planner

Open the pour day planner →

Change one thing at a time

Almost every candle problem has more than one possible cause, and the causes overlap. Soot can come from a big wick, a heavy oil or a draft. A weak scent can be the cure, the wick or the load. The only way to know which is to change one thing and test again beside a control candle that has not changed. That is slower than changing everything at once, but it is the only way to learn what your wax and jars actually need.

Cosmetic or real?

Some issues look bad but do not affect the burn: wet spots, frosting and jump lines. Customers sometimes ask about them, and many makers add a short note on the listing explaining that natural soy can frost. Others, like tunneling, soot and a sweating surface, mean the candle is not performing as it should and is worth fixing before you sell.

Keep a burn log

Write the wax, wick, load, pour temperature, room temperature and cure time for every test. When something goes wrong, the log tells you what changed. The wick test planner prints one for you.

The questions to ask first

  1. Is the fragrance load within your wax’s published maximum? Check it on the wax specs page.
  2. Did you add oil at the add-oil temperature and stir for a full two minutes?
  3. Did you pour within the wax’s pour range?
  4. Has the candle cured for the time the wax maker suggests?
  5. Was the wick tested in this exact jar with this oil and dye?

If the answer to all five is yes and the problem remains, the wick is the most likely next thing to test.

Read our guides

How to run a wick test that actually tells you somethingA step-by-step wick test: choosing three sizes, pouring and curing the test jars, the four-hour burn, and how to read melt pools, flames and soot.Wet spots and frosting: what they are and when to worryAnswers to the most common questions about wet spots and frosting on soy candles: causes, whether they affect the burn, and what reduces them.

Questions makers ask

Why is my candle tunneling?

Usually the wick is too small for the jar, or the first burn was too short to melt all the way to the edge. Test a size or two up, and burn new candles long enough on the first light.

Are wet spots a defect?

They are cosmetic. The wax has pulled away from the glass in places as it shrank. The candle burns the same. Warming jars before pouring and cooling slowly help.

Why is there oil on top of my candle?

The fragrance load is probably higher than the wax can hold, or the oil was added too cool or stirred too briefly. Check the load against your wax’s maximum.

Why can’t I smell my candle when it burns?

Most often it needs a longer cure or a bigger wick. Soy wax can need one to two weeks to reach full hot throw.

What is frosting?

White crystal growth on soy wax. It is natural and harmless. Pouring at the right temperature and steady storage reduce it.

Sources we checked

  1. Fillmore Container: soy wax troubleshooting guide
  2. CandleScience wick guide: testing advice
  3. Lone Star Candle Supply: dos and don’ts of candle making

Numbers last checked 2026-10-21. How we check them. If your supplier says something different, tell us.

Next on the bench

Wick Test PlannerA starting wick for your wax and jar, the two sizes to test beside it, and a printable burn log.Fragrance Load CalculatorOil for your wax, both meanings of “10%”, and a check against your wax’s limit.Candle Wax Specs ComparedMax fragrance load and pour temperature for popular waxes, as each supplier publishes them.