Candle Making 102: What Are Wet Spots & Why Do They Happen?

At Grow Light Forever, we love helping candle makers, from beginners to seasoned pros, understand the science behind their craft. One of the most common questions we hear is: “What are wet spots and how do I stop them?”

If you’ve ever noticed your candle wax pulling away from the glass in certain areas, giving it a patchy, wet look, that’s what we call a wet spot. But don’t worry, it’s not actually wet, and it doesn’t mean anything is “wrong” with your candle.

Why Do Wet Spots Occur?

The explanation is simple science.

When wax is heated, it expands. As it cools and solidifies, it contracts. During this contraction, the wax sometimes pulls away from the glass, creating those wet-looking patches.

The biggest culprit? Temperature variation.

Even if your candle studio is perfectly controlled, once your candle leaves your hands, it goes through warehouses, delivery vans, shops, and different climates. Hot and cold conditions naturally cause wax to shift and move inside the container.

Do Wet Spots Affect Candle Performance?

Nope! Wet spots don’t impact scent throw, burn quality, or the overall performance of your candle. Makers often notice these little details, but most customers don’t. If you browse store shelves, you’ll see wet spots in many well-known candle brands too. It’s completely normal and doesn’t affect quality.

Can You Prevent Wet Spots?

Unfortunately, you can’t stop them entirely, temperature is always changing. But there are ways to reduce their appearance:

Preheat your glassware, This helps wax and glass cool together, reducing shrinkage.

Experiment with pouring temps, With soy wax, try pouring a few degrees cooler than recommended and record your results.

Use opaque jars, If you can’t see them, they won’t bother you (or your customers).

Switch wax types (last resort), Some waxes adhere better, but testing is required and wet spots can still happen.