Why Are My Candles Cracking?
You pour a fresh batch of candles, everything looks fine, then the surface splits. A thin crack in a circle on the candle surface. Maybe a deep split across the top. So what’s going on?
Candle cracking is one of the most common issues in candle making, especially with soy wax. The good news? It’s usually cosmetic and completely fixable. But if you want smoother tops and a more professional finish, let’s break down what causes cracks, and how to prevent them.
Why Are My Candles Cracking?
Cracking happens when the wax cools too quickly or unevenly. As wax contracts while it sets, any sudden change in temperature can cause surface tension that leads to splits, especially on the top layer.
Other times, the issue starts before the pour: wax that’s too cool, equipment that’s too cold, or environmental shifts in the workspace can all contribute to the problem.
Common Causes of Cracks in Candles
1. Pouring Wax at the Wrong Temperature
If you pour too cool, the wax may begin setting before it fully levels out in the container. Soy wax is especially sensitive to temperature, and slow cooling helps prevent cracking.
Try this: Stick within the recommended pour temp for your specific wax. For most soy waxes, that’s around 120°F–135°F. Too hot, and you risk frosting or sinkholes; too cool, and you’ll likely see cracks.
2. Cold Containers or Workspace
A cold jar, tin, or room can shock the wax as it hits the surface. That quick temp drop locks the top before the rest settles underneath, leaving you with a cracked candle top.
Fix it: Pre-warm containers slightly with a heat gun or in a warm oven (under 100°F). Keep your workspace above 70°F when pouring.
3. Improper Cooling Conditions
If you move candles too soon, set them near a draft, or let them cool unevenly, the top layer can form cracks.
Tip: Let your candles cool slowly in a stable, draft-free space. Don’t refrigerate them or place them on cold surfaces like stone counters.
Why Are My Homemade Candles Cracking More Often?
Homemade candles, especially soy, tend to crack more than paraffin-based blends because of how natural wax behaves. Soy wax expands and contracts more during the cooling process, making it more vulnerable to cosmetic flaws like frosting, rough tops, and cracking.
If you're working with a 100% soy wax blend, dial in your pour temp and container temp, and allow time for a gradual cool-down. Using a soy-paraffin blend or adding a small percentage of coconut wax can sometimes help with texture and finish.
How to Fix a Cracked Candle
If your candle cracked on top but everything else looks good, don’t toss it. Here are a few quick fixes:
- Use a heat gun: Lightly reheat the top of the candle until the wax melts just enough to level out. This smooths over most surface cracks.
- Top it off: If the crack is deep, melt a small amount of the same wax and pour a thin layer over the top to even it out.
- Repour and remix (if needed): For persistent cracking, revisit your wax temp, container conditions, and any additives you’re using.
How to Prevent Candles from Cracking
Preventing cracks is about controlling your environment and knowing your materials. Here's what helps:
- Keep pour temperatures consistent and in range
- Pre-warm containers, especially in cooler months
- Avoid drafts or extreme temperature swings
- Allow slow, uninterrupted cooling
- Use waxes with smooth finish characteristics if surface appearance is a priority