Candles Keep Tunneling? Here’s Why

Whether you make your own candles or buy them from high-end stores, if you don’t take proper care of them, they may be prone to tunneling. Do your candles keep tunneling? Here’s why:

Tunnelling can be caused by defects in candle construction, not taking proper care of a candle, and cold temperatures. Candle tunneling is most likely caused by:

  1. Untrimmed wicks
  2. Incomplete initial burn
  3. Wrong wick size
  4. Cold temperatures

Why Are Your Candles Tunneling?

Tunneling occurs when only the wax immediately around the wick melts instead of the wax pool reaching all the way to the sides of the container. This causes the candle to burn incompletely, creating a tunnel in the center of the candle. 

Tunneling is a major defect that causes two main problems. First, most of the wax will not melt, resulting in your candle reaching its end of life early. Second, if the tunnel is too deep, not enough oxygen will reach the wick, meaning the candle won’t stay lit.

Either situation results in sub-optimal candles with major quality control issues.

Tunneling can be caused by poor candle maintenance, improper candle construction, or even temperatures that are too cold. Let’s take a closer look at each of these to try and diagnose why your candles keep tunneling. 

Problem 1: Untrimmed Wicks

I was guilty of this myself until I learned better. Our ancestors were used to relying on candles for every aspect of their lives, from the spiritual to providing light and warmth in their homes, so they did a much better job maintaining their candles than we do today. One of the lessons that has been lost over the years is the need to trim candle wicks. 

Why Trimming Matters

Please note that the contents of this blog are for informational and entertainment purposes only and should not be construed as legal advice. Any action taken based on the information provided in this blog is solely at your own risk. Additionally, all images used in this blog are generated under the CC0 license of Creative Commons, which means they are free to use for any purpose without attribution.

Wicks that are too long can make your candle tunnel. This is because they create a flame that is too large, superheating the wax in its immediate vicinity. This causes the candle to burn down instead of recruiting the surrounding wax to create a wax pool that reaches all the way to the sides of the container. 

This is the easiest form of tunneling to prevent and fix. Just trim the wick to the proper length before each burn of your candle.

How to Trim Your Wick

You can use scissors, nail clippers, or a wick trimmer to shorten your weeks. Scissors are fine at first but as your candle burns below the surface of the container, it will be harder to angle the scissors correctly to get to the wick. In this case, nail clippers or a dedicated wick trimmer are better options.

How long should your candle wicks be? This is a matter of some debate. Some candle enthusiasts say 1/8”, while others say 1/4”. Still others say anywhere between the two.

I am firmly in the camp that believes 1/4” is a proper candle wick length. It’s a good starting length anyway. If you notice the wick is smoking and creating too much soot, you can cut it to 1/8”. It is always easier to deal with a wick that is too long than one that is too short. 

Problem 2: Incomplete Initial Burn

You can’t just burn your candle for an hour, extinguish it, and then expect it to behave properly the next time around. That’s because candle wax has a memory. If you don’t activate the memory properly on a candle’s initial burn, the candle will be prone to tunneling. 

Failing to create an adequate-sized wax pool on the first burn means the wax immediately around the wick will be weaker, making your candle melt down the center, creating the dreaded tunnel. 

How do you know if the wax pool is the right size? A candle’s wax pool should reach all the way to the sides of the container and should be 1/4” to 1/2” deep. 

How Long Should the Initial Burn Be?

The initial burn is the most important burn because it determines how the candle will burn for the rest of its life. The short answer is the initial burn should be at least as long as it takes to achieve the right-sized wax pool.

In terms of length of initial candle burn, some recommend a round figure of three hours. I recommend burning your candle for at least one hour per inch of diameter. For very large candles, this might mean that your first burn should be at least four hours for a candle that is four inches in diameter.  

Claire’s Crafty Corner has a great tutorial on how to burn your candle the right way, including the initial burn. 

Problem 3: Incorrect Wick Size

The first two tunneling problems are caused by incorrect candle maintenance, while this one is caused by improper construction. 

Of all the components in a candle, the wick is the most important. The wick affects every aspect of the candle, from its scent throw to how it burns and even if it burns at all.

If the Wick is Too Small…

Candles Keep Tunneling? Here’s Why

The size of a wick refers to its diameter. As the candle burns, this determines the temperature the flame will reach, as well as the surrounding wax. The thicker a wick, the hotter it will burn. 

If the wick is too small, it can’t heat the wax to the right temperature. In some cases, the wax near the edge of the container won’t get warm at all, and the candle will tunnel.

There are plenty of online calculators to help you figure out the correct wick size for your candle. I use these, but there are a lot of variables to correct wick size, including what the wick is made of.  That’s why I like to use this wick sampler to help me experiment with different sizes. 

If the Wick is Too Large…

Paradoxically, wicks that are too large can also cause tunneling. Each candle has a specific balance to how it is supposed to burn and if the wax surrounding the wick becomes too hot, the candle will tunnel. 

When it comes to wicks, always follow the Goldilocks rule… they must be just right.

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Problem 4: Cold Temperatures

Ever think about how temperature affects your candle burning?

If you try to burn your container candle in temperatures that are too cold, you might experience candle tunneling. This is because even if you have the right sized wick and conduct correct candle maintenance, the wax will have a hard time heating to the proper temperature. The wax closest to the wick will melt first, creating a tunneling effect in cold temperatures.

How to Prevent Cold Weather Tunneling

There are several ways to deal with the predisposition of a candle to tunnel in cold weather. 

First, you can make sure you burn your candle in temperatures 67 to 82 degrees Fahrenheit (20 to 28 degrees Celsius). 

But this is not always possible if you like to burn candles when camping or other outdoor settings. For these situations, you can at least make sure you conduct a proper initial burn or design a special candle for cold weather use, with a thicker wick than you would normally use in an indoor setting.

Make sure you burn test your candles in the same conditions as you plan to use them.

How to Fix Tunneling Candles

If all else fails, and your candle has tunneled anyway, don’t despair. There are two methods you can use to rescue a tunneling candle. 

Hair Dryer

Optimally, you would use a heat gun, but a hair dryer on the hottest setting should also do the trick. 

With the candle not lit, gently heat the top of the candle until an adequate-sized wax pool has formed and the wax is flat. If the tunnel is deep, you can use tweezers to pull the wick up so the wax settles in a plane around it.

Foil Method

This is the best method for dealing with a tunneled candle. Cover the top of your candle with a piece of aluminum foil and cut a 1” hole around the wick. Then you just need to light the candle. The heat retained by the foil will help create a good wax pool. 

Once the wax pool is formed and is flat, you can remove the foil. Your candle is repaired and should burn normally for the rest of its life. 

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Frequently Asked Questions

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How can I fix my candle that has tipped over and tilted the surface of the wax?

If your candle tipped over when it was warm and the wax cooled in a slanted position, you can use either one of the tunneling repair methods listed above to fix it.

Do pillar candles ever tunnel?

Generally, one advantage of candles without a container, also known as “pillar” candles, is they are not prone to tunneling. Tunneled pillar candles are more difficult to fix than tunneled container candles. Only the hair dryer/heat gun method will work. 

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Please note that the contents of this blog are for informational and entertainment purposes only and should not be construed as legal advice. Any action taken based on the information provided in this blog is solely at your own risk. Additionally, all images used in this blog are generated under the CC0 license of Creative Commons, which means they are free to use for any purpose without attribution.

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