Why Did My Candle Sink in the Middle? Troubleshooting Common Candle Making Issues

Quick Answer

If your candle sinks in the middle, it's usually because the wax cooled too quickly or unevenly, creating a void around the wick. The fix is simple: use a heat gun or hairdryer to remelt the surface, or do a second pour with reserved wax. For persistent issues, check your pouring temperature and wick selection.

You've carefully poured your candle, waited for it to set, and then noticed an annoying dip around the wick. This is one of the most common candle making problems, and it's completely fixable. Understanding why it happens helps you prevent it next time.

Sink holes occur when the outer layer of wax hardens first, trapping air that contracts as it cools. The result is a crater-like depression. The good news: you can repair most sink holes in minutes, and with a few tweaks to your technique, you'll avoid them altogether.

Why Does a Candle Sink in the Middle?

The main culprit is rapid cooling. When hot wax is poured into a container, the sides and bottom cool faster than the center. As the wax solidifies, it shrinks, pulling the still-liquid center downward. If the top skin hardens before the air escapes, it creates a vacuum that collapses into a sink hole.

Another factor is pouring at too high a temperature. Wax that's too hot cools more dramatically, increasing shrinkage. Also, if the room is cold or drafty, the temperature difference between the center and edges becomes more pronounced, worsening the problem.

• Always pour at the recommended temperature for your wax type.
• Keep your workspace at a steady room temperature, away from drafts.
• Reserve a small amount of wax for a second pour if needed.

How to Fix a Sink Hole in a Candle

The easiest fix is to remelt the top surface. Use a heat gun on low setting or a hairdryer on high heat, moving it in circular motions over the sink hole. The wax will melt and fill the void. Allow it to cool slowly at room temperature. This works best for shallow sink holes.

For deeper holes, do a second pour. Melt a small amount of the same wax, heat the existing candle's top with a heat gun to ensure bonding, then pour the melted wax to fill the hole. Let it cool slowly. If the issue repeats, you may need to adjust your pouring temperature or wick size.

• Use a heat gun or hairdryer for quick fixes on shallow sink holes.
• For deep holes, do a second pour with reserved wax.
• Always let candles cool slowly at room temperature.

Preventing Sink Holes in Future Batches

To avoid sink holes, pour your wax at the correct temperature—typically between 120°F and 160°F (49°C to 71°C) depending on your wax. Check the manufacturer's guidelines. Also, pre-warm your containers to reduce the temperature difference between the wax and the container.

Another trick is to tap the container gently after pouring to release air bubbles. Some crafters also use a heat gun to keep the surface molten for a few minutes, allowing trapped air to escape. Always cool candles slowly in a warm, draft-free area.

• Pre-warm containers to minimize temperature shock.
• Tap the container after pouring to release air bubbles.
• Cool candles slowly in a warm, draft-free spot.

Diagnosis: When to Fix vs. When to Start Over

• Symptom: Shallow sink hole (less than 1/4 inch deep): This is common and easily fixed. Use a heat gun or hairdryer to remelt the surface and let it cool slowly.
• Symptom: Deep sink hole (more than 1/4 inch deep): The wax contracted significantly, often due to pouring too hot or cooling too fast. Do a second pour with reserved wax, ensuring the existing top is heated for bonding.
• Symptom: Sink hole appears repeatedly even after fixing: This indicates a systemic issue with your pouring temperature, wick size, or cooling environment. Adjust your technique: pour at a lower temperature, use a smaller wick, and cool in a warmer room. If problems persist, consider trying a different wax or consulting a candle making guide.

Products to Help You Troubleshoot

• Sculpd Pottery Kit: Your All-In-One Pottery Kit for At-Home Creativity. Create your own handmade homeware - from pinch pots and vases to candle holders and sculptures. Each kit includes everything you need to sculpt, carve, paint and seal your creations. We use a premium air-dry clay that’s soft, smooth, and seriously satisfying to shape. If you're making your own candle holders, this kit lets you craft a unique vessel. The air-dry clay dries to a beautiful light grey, perfect for painting to match your candle.
• Sculpd Pottery Kit: Your All-In-One Pottery Kit for At-Home Creativity. Create your own handmade homeware - from pinch pots and vases to candle holders and sculptures. Each kit includes everything you need to sculpt, carve, paint and seal your creations. We use a premium air-dry clay that’s soft, smooth, and seriously satisfying to shape. If you're making your own candle holders, this kit lets you craft a unique vessel. The air-dry clay dries to a beautiful light grey, perfect for painting to match your candle.

Sink holes are a common candle making issue, but they're easy to fix and even easier to prevent with a few adjustments. Remember to pour at the right temperature, cool slowly, and keep a heat gun handy for quick repairs. With these troubleshooting tips, you'll create smooth, professional-looking candles every time.