What Causes A Mushrooming Candle Wick and How Do You Fix It

Mushrooming candle wick

If you often burn candles then a ‘mushrooming’ wick is likely a phenomenon that you have seen before. It is an unsightly black ball that builds upon the end of the wick. It can make the candle burn irregularly and fall off and make the candle look dirty. Let’s take a closer look at what this actually is and what causes it. What causes a mushrooming candle wick?

Mushrooming wicks are caused by carbon buildup on the end of the wick. This happens because the wick pulls up more wax than it can burn. This is due to the wrong wick being used when the candle was made or too many additives being used in the candle wax. However, some wicks can naturally mushroom.

Candles with mushrooming wicks can burn with a larger and brighter flame causing an irregular burn and producing soot as they burn. I have even seen glass containers burst when a large mushroomed wick burns too closely to the side of the container. Wax ended up going all over my desk, it was not a pretty sight.

Sometimes a mushrooming wick is as simple as the wick is too large for the candle, the type of wax, and fragrance oil. However, this phenomenon can have other causes and explanations that should be addressed. Let’s dig a little deeper and see how we can prevent it.

Mushrooming Candle Wick

Mushrooming Wick Risks

When carbon builds upon the end of a wick a ball of carbon forms what people refer to as a ‘mushrooming wick’. It is essentially caused by a candlewick pulling up more wax than it can burn at once leaving a partially burned carbon deposit on the end of the wick. This is usually accompanied by an irregular flame that produces soot.

The carbon ball on the end of the wick produces a larger and brighter flame that burns hotter. This can fall off in to the molten wax pool discoloring it making your candle look dirty and in the worse case scenarios it can be a fired hazard.

As I mentioned earlier I had a candle burst due to a mushrooming wick. I hadn’t left the candle unattended but I was working at my computer and not paying close enough attention to the candle. When the side of the glass container burst, molten wax poured out on to my desk and the burning wick leaned over with the wax and continued burning.

I blew the candle out and started cleaning up the molten wax and glass shards and it was only a slight inconvenience and cost me a cheap grocery store candle. However, this is the type of accident that can lead to an unattended candle burning your house down.

Mushrooming candles are most often a sign that the wick is too large for the candle.

Mushroom Wick Causes

There are several potential causes for mushrooming wicks and most of them fall on the shoulders of the candle maker.

However, there are still a few things that the average candle user can do to help prevent this from ruining their candle and their candle burning experience.

Wrong Wick size

A wick that is too large for a candle will pull more wax-up than it can burn at once. This leaves partially burned hydrocarbons to build upon the top of the wick causing a “mushrooming wick”.

This buildup means you now have a larger flame that is producing more heat. This heat is bad for your candle in a few ways. One way is that it becomes a threat to the container itself as you’ve read above. The second is that it can essentially ruin your scented candles scent. The third is that it takes away from the aesthetics of your candle.

A larger hotter flame can make your fragrance additive evaporate before it normally would have and lessen the scent throw of your candle. Personally, this one bothers me the most, some of these scented candles are quite expensive and I want to get my money’s worth until the candle has burned all the way down.

Wrong Wick type

Wick type is also a potential cause for mushrooming wicks. According to CandleScience CD wicks can be more prone to mushrooming than other types of wicks.

CD wicks are wicks that are designed for softer types of wax, such as soy and consist of flat braided cotton with paper threads. They are also often used in candles that carry higher scent loads.

Zinc core wicks are also culprits when it comes to mushrooming wicks. A zinc core wick is a braided cotton with an inner zinc core and it is designed for maximum rigidity and to stay straight as the wax around it melts down.

Zinc core wicks are prone to mushrooming because they do not self trim like some other types of wicks.

Type of Wax

Soy candles have a reputation for mushrooming wicks, however, any wax is capable of making a wick mushroom under the right conditions. I believe it has more to do with the total combination of wax, wick, and fragrance. The benefits soy wax brings to candle making far outweigh any slight problem with mushrooming that may be attributed to them.

Burn Time

Nearly every type of candle will experience some form of mushrooming after you burn them long enough. Most candles come with a manufacturer suggested burn time

This is a minimum amount of time you should burn a candle and a maximum amount of time you should burn a candle. If you do not let the candle burn long enough you might experience wax tunneling, if you let it burn too long you will experience mushrooming.


The fragrance used in candles can also contribute to a mushrooming wick. It can be impacted by the type of fragrance and the load of the fragrance being used.

Scents and fragrance oils used in candles can change how they burn and the size of the wick required and can easily lead to a situation in which you make a candle that has a mushrooming wick.

Candle Maintenance

Candle maintenance is an important thing for avid candle users to stay on top of because let’s be honest, not every candle you order is going to burn perfectly, not even ones you get from big-name brands and boutique candle shops. Keep an eye on the length and condition of your wick and keep it trimmed.

Fixing Mushrooming Wicks

While mushrooming wicks can be a problem at times, it is a problem you can fix.

How to fix a mushrooming wick?

  • Proper candle maintenance
  • Using correct burn times

Lets take a closer look at what that means.

Proper Candle Maintenance

If you have a candle that appears to be prone to a mushrooming wick you need to exercise proper candle maintenance. I would suggest getting a candle accessory set with a tray from Amazon first.

After every candle burning session check your wick and if you see a ball forming on the tip of it or if it is too long trim it down to about 1/4 of an inch.

If you do not want to extinguish the flame to trim the wick you can bend the wick over with the tip pointing down toward the wax pool. This will help prevent the partially burned hydrocarbons from building up on the tip that causes that mushrooming wick shape.

Correct Burn Times

You will find that some candles come with what are known as maximum session burn times that exist to help prevent wick mushrooming. You might find this on your candle packaging, the manufacturer website or perhaps you can call someone and ask them.

In addition, candles have minimum session burn times that help prevent wax tunneling. You can find out more here about what happens when you burn a candle too long.

Prevent Mushrooming Wicks

Mushrooming wicks can even be prevented during the candle making process.

How to prevent mushrooming wicks?

  • Use quality fragrance oils
  • Proper wick types
  • Proper wick size
  • Use suggested load percentages

Here is a more in-depth look at what that means.

Buy Quality Fragrance Oils

With some suppliers, you don’t really know what you are getting. If you buy some fragrance oil off of eBay or Alibaba then you might be getting a low-quality product. My advice is to stick with well known and reputable suppliers and if you are going to try a new supplier then test their fragrance oils in small doses

Use The Proper Wick Type

Some wicks are designed to be used with certain waxes and fragrances and you can find the suggested combinations from most wholesale candle suppliers. As mentioned above, stick with what you know works.

Use The Proper Wick Size

The conventional wisdom with wick size is that whatever size wick a candle with no dye or fragrance oils uses, then you need to use one size bigger after adding fragrance oils and dyes. That is how much they impact the way a candle burns.

The good news is that most wholesale candle suppliers take this in to account when giving you their suggested wax, wick, fragrance oil load combinations.

Use Suggested Fragrance Oil Load Percentages

If you overload your candles with fragrance oils then you are asking for trouble. Not only can it break down the wax preventing it from curing properly it can cause mushrooming wicks and even be a fire hazard.

Frequently Asked Questions

How do you stop Wick mushrooming?

Stop wick mushrooming by keeping your candle wick properly trimmed to manufacturer’s suggested lengths. In addition, follow the manufacturer suggested burning practices and do not burn your candle too long. Burning a candle too long can contribute to carbon buildup on the wick.

Is a mushrooming wick bad?

Mushrooming wicks are not bad or good, it is just carbon buildup on your candle wick. This is a natural part of the candle burning process and a common occurrence with many types of candle wicks. Mushrooming is often seen on wicks that have not been properly trimmed.

Are you supposed to cut candle wicks?

You should cut your candle wick to a length of approximately 1/4 of an inch after every use. This trimming of the wick will ensure you get a stable and uniform flame while preventing carbon buildup on the wick, also known as “mushrooming”.


In conclusion, there are a variety of causes for potential reasons candles developing mushrooming wicks. The best way for the average candle user to address this problem is by having a candle accessory kit. They serve a useful purpose if you use a lot of candles and save you from making a mess with your scissors or butter knife. I do not use mine too often but when I do use them, I am glad to have them

The candle maker that is trying to prevent mushrooming wicks in their candles has a slightly more difficult task at hand. My main suggestion is to follow manufacturer and wholesaler suggestions in regard to wax type, wick type and size, fragrance oil, and fragrance oil load.

If you decide you want to try something new then do so in small batches and allow the candles to cure for the proper amount of time before using them. Write down everything you did and all measurements involved. Then when you are ready to scale up production you should be covered.

Mushrooming Candle Wick

Carl Adamson

Hi, I'm Carl Adamson, one of the founders here at Candleers. A few years ago I got really into the art and craft of candle making, initially with soy wax container candles. My friends started asking me to make candles for them and pretty soon it turned into a nice side-business. I started this website as a way to document what I've learned over the past few years and hopefully help others in the process. I still love candle making but I'm learning that what I enjoy even more is the business side of things - and for this reason I've started consulting others on how to start and grow their own candle-making businesses and side-hustles.

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