When making container candles, one of the most common cosmetic issues is poor glass adhesion, where the wax pulls away from the sides of the glass, leaving wet spots or air pockets. While this doesn’t affect the safety or scent throw of the candle, it can make the candle look less professional.
What causes poor Glass Adhesion?
Wax Shrinkage
Wax naturally contracts as it cools. If the jar cools faster than the wax, it can separate
Temperature shock
Pouring hot wax into a cold container creates uneven cooling, causing air pockets
Air Bubbles
Rapid stirring or improper pouring introduces air between the wax and glass.
Wax type
Soy wax and other natural waxes are more prone to adhesion issues than paraffin
How to Prevent Glass Adhesion Problems
Prepare your jars
Clean your glass before pouring and ensure the jar is dry. Preheat containers approximately 38-49 degrees, depending on which wax you’re working with. You want the glass to be at a similar temperature to the wax, so there’s no sudden temperature difference.
Control your pour temperature
Follow the manufacturer’s recommended pour temperature, avoid pouring wax that’s too hot, as this creates shrinkage. Make sure you are pouring consistently and don’t change temperatures between batches.
Create the right cooling environment
Place jars on a towel, cardboard, or wood surface. Avoid metal & stone surfaces as they tend to be cold surfaces. Allow candles to cool at room temperature in a draft-free space, avoiding fans, AC vents or sudden temperature changes.
Mix & Pour carefully
Stir fragrances slowly to reduce bubbles and pour gently down the side of the jar instead of directly into the centre. When you have finished pouring, tap the jars lightly to release trapped air.
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