The short answer
Wet spots are places where the wax has pulled away from the glass as it cooled and shrank, so the jar looks wet or patchy there. They come from uneven cooling: cold jars, drafts, a cold room or a pour temperature far from your wax’s recommendation. They are cosmetic and do not change how the candle burns. Warm, clean jars and slow, even cooling reduce them.
What a wet spot actually is
Nothing is wet. Wax expands when it melts and shrinks as it cools and hardens. When one part of the candle cools faster than the part beside it, the shrinking wax lets go of the glass in that area. Light now passes through an air gap instead of wax pressed against glass, and that patch looks darker and “wet” next to the parts that stayed stuck.
Wet spots are different from frosting. Frosting is a white, powdery or crystal-like film on the wax itself; a wet spot is a gap between the wax and the jar. If you see white bloom, read Candle Frosting instead.
Cosmetic, not a burn problem
Suppliers agree that wet spots are a looks issue: the candle still burns normally. Whether to chase them is a question of how you want your candles to look on a shelf, not of performance.
Why wet spots happen
Almost every cause comes back to one thing: parts of the candle cooling at different speeds.
| Cause | What happens | What to change |
|---|---|---|
| Cold jars | Hot wax hits cold glass; the outer layer sets fast and shrinks away | Warm the jars before pouring (see the temperatures below) |
| Drafts, fans, vents, open windows | One side of the jar cools faster than the other | Cool candles in a still room, away from vents and doors |
| A cold or changing room | The whole batch cools too fast or unevenly | Keep the room steady while candles set |
| Pouring far from your wax’s recommended temperature | Too hot means more shrinkage as it cools; too cool can mean poor contact with the glass | Pour at the temperature on your wax’s data sheet, then adjust in small steps |
| Candles crowded together or on a cold counter | Jars in the middle of a group stay warm while the outer ones cool; stone counters pull heat from the base | Space jars apart and cool them on a wire rack |
| Dusty, oily or damp jars | Wax does not grip a dirty surface well | Wash jars and dry them fully before pouring |
| Movement while setting | Moving or bumping a candle can break its contact with the glass | Leave candles where they are until they are fully set |
| Your wax | Some soy waxes shrink more and hold the glass less well than others | If nothing else helps, ask your supplier about a wax formulated for better glass adhesion |
Wet spots can also show up later, after the candle has set, if it is moved between a warm room and a cold one. Shipping and storage in a cold car or warehouse can do it.
How to prevent wet spots
- Start with clean, dry jars. Wash them with soapy water and let them dry completely.
- Warm the jars. Suppliers recommend warming jars before you pour; the figures they give range from about 90°F to 120°F (32–49°C) — see the table below. A low oven or a heat gun both work. Warm, not hot.
- Pour at your wax’s recommended temperature. Your wax’s technical data sheet is the authority. If wet spots keep appearing, adjust in small steps (suppliers suggest about 5°F at a time) and note the result.
- Pour slowly and tap the side of the jar gently to release air bubbles.
- Cool slowly and evenly. Set the jars a few inches apart on a wire rack, in a room with a steady temperature and no drafts. Do not put them in the fridge or near a fan or window.
- Leave them alone until they are completely set.
Published room and jar temperatures differ a little from supplier to supplier. None of them is a rule; they are starting points to test.
| Supplier guidance | Warm the jars to | Room while cooling |
|---|---|---|
| One supplier’s soy troubleshooting guide | About 100°F (38°C), not above | 70–76°F (21–24°C) |
| The same supplier’s smooth-tops guide | 90–100°F (32–38°C) | 68–72°F (20–22°C) |
| Another supplier’s wet-spots guide | 100–120°F (38–49°C), for a few minutes | 70–75°F (21–24°C) |
Change one thing at a time
If you warm the jars, change the pour temperature and move to a new room all at once, you will not know which one fixed it. Change one, pour a few jars, and write down what happened. A testing log makes this easy.
How to fix wet spots on finished candles
You can sometimes re-attach the wax by warming the outside of the jar with a heat gun on a low setting, moving it constantly over the wet area until the wax against the glass softens and settles back. Let the candle cool slowly again afterward.
- Work on a heat-resistant surface and keep the heat gun moving so no spot of glass gets very hot.
- Stop as soon as the wax against the glass looks uniform; you only need the outer layer to soften.
- Expect some wet spots to come back if the candle later goes through big temperature swings.
Glass and heat
Glass can crack when one spot is heated or cooled quickly. Keep the heat low and moving, never heat a jar that has a crack or chip, and let it cool on its own — never under water or in the fridge.
If a fix is not worth the time, that is a fair choice too. Many makers of soy candles accept a few wet spots and tell their customers what they are.
Explaining wet spots to customers
If you sell soy or other natural-wax candles, a short line on your product page or care card heads off questions: wet spots are wax that has pulled away from the glass as it cooled, they are cosmetic, and the candle burns the same. Keep it factual. Do not promise that a candle will never have them — temperature changes in shipping can create them after the candle leaves you.
Common questions
Do wet spots affect how a candle burns?
No. Suppliers describe wet spots as a cosmetic issue. The wax has only separated from the glass; the candle burns the same.
Why do my soy candles always get wet spots?
Soy wax shrinks as it cools, and some soy waxes hold onto glass less well than others. Cold jars, drafts and uneven cooling make it worse. Warm clean jars, pour at your wax’s recommended temperature and cool the candles slowly in a still room.
Should I preheat jars before pouring candles?
Suppliers recommend it to reduce wet spots. Their published figures range from about 90°F to 120°F (32–49°C). Warm the jars, do not make them hot, and pour soon after.
Can I get rid of wet spots after the candle has set?
Sometimes. Warming the outside of the jar gently with a heat gun on low can let the wax settle back against the glass. Keep the heat moving, and let the candle cool slowly afterward.
What is the difference between wet spots and frosting?
A wet spot is a gap between the wax and the glass, so the jar looks wet in patches. Frosting is a white, crystal-like film on the wax itself. Both are cosmetic.
Sources
- How to Fix Wet Spots in Soy Candles — Makesy
- Soy Wax Troubleshooting Guide — CandleScience
- Candle Making 101: Smooth Tops — CandleScience
Updated October 5, 2026. These guides are starting points — always burn test your own candles.