Why Does My Candle Jar Turn Black? (And How to Prevent It)

Burning a candle in your home is a great way to boost your mood and create a relaxing atmosphere. However, sometimes if you’re using a candle that has a jar, black smudge marks can form will often dampen the cozy atmosphere is are quite unsightly. Many new candle users have this problem, and it can be quite frustrating if your candle jar turns black and you don’t know why or how to prevent it.

Burning a candle produces many byproducts that disperse into the air unnoticed, but some candles release unburned carbon that can collect in the form of black smudge marks called soot. Properly maintaining your candle and getting one with very few additives in the wax can help prevent soot buildup. 

Now that you know the basics of why your candle jar turns black sometimes and what that buildup is, let’s take a more in-depth look at the whole situation. There is much more nuance to this than you might expect, so let’s jump right into it and figure out what exactly causes soot buildup, how to prevent it from happening, and much more!

Why Does My Candle Jar Turn Black

What Causes My Candle Jar To Turn Black?

When the jar turns black after burning your candle, it is the buildup of soot. Put simply, soot is when unburned carbon atoms are released from your candle’s wick and collect on the side of the jar. But why do some candles produce a lot of soot and others do not?

Well, it actually comes down to specific attributes of certain candles. Below I’ll go over some of the significant characteristics found in candles that produce lots of soot.

Too Many Additives in the Wax

The wax used to make candles is usually not pure wax. In fact, most candles you can purchase today have many additives meant to make the candle burn longer, smell more pleasant, or do various other tasks.

Not all additives in candles are bad, but sometimes a candle can have TOO MANY additives or too high of a concentration of a single additive. A properly formulated candle should not have this problem of too many additives, but if you make your candles at home, too much fragrance or other ingredients could lead your candle to produce more soot.

Read more about Best Soy Wax For Candle Making.

Wick Length and Size

The correct length and size of a wick are crucial for a candle to burn correctly. A larger candle will usually need a larger wick than a smaller candle. There is quite a bit of trial and error testing and knowledge that goes into choosing the right wick length and size for a candle, so if you are making your own candles, do your research and conduct plenty of tests.

An improperly sized wick will make a candle have all sorts of problems and issues when burning. Too much carbon will often be produced and can lead to an increase in soot production. An incorrectly sized wick can also make your candle burn unevenly, too fast, or too slow in addition to the added soot.

Wick Material

If that wasn’t enough to worry about already, what material your candle’s wick is made of can also influence how much soot your candle makes. Most jar candles will have cored wicks, which means the wick has a cross-section made out of a specified material. What material is used to make the core of your candle’s wick is the variable in whether your candle will put off a lot of soot or not.

While there are TONS of different types of cored wicks, certain ones are known to make more soot than others. According to Candles.org, “the most common core materials for wicks are cotton, paper, zinc or tin.” Out of these materials, paper and cotton tend to produce much less soot than zinc or tin cored wicks.

Excess or Lack of Airflow

How much oxygen and fuel a candle gets can be significantly impacted by how much airflow the candle receives. To produce the least amount of soot possible, you usually want to be in the middle ground where there isn’t excess airflow, but there isn’t a lack of airflow either.

Too many drafts or excess air movement around your candle will make the flame flicker and burn more wax. This increased fuel usage will usually cause unburned carbon atoms to be released and will form soot on the jar of your candle. On the flip side, once your candle burns low into the jar, or there is a restriction of airflow in the environment for some reason, soot production will usually increase. 

How To Prevent Your Candle Jar From Turning Black

Once you know a little bit about what can cause your candle to produce soot, the logical next question is how to prevent it from happening. And while there is no method to guarantee your candle won’t produce soot at all, there are some steps you can take to significantly take down the chances of your candle putting off a large amount of soot. 

So let’s just jump right into some of the ways you can prevent your candle jar from turning black from soot!

Use Good-Quality Candles

While it might seem a little bit obvious, one of the BEST things you can do to cut down on soot production is by getting a good-quality candle. By simply taking the time to find a good quality candle, most of the problems that cause a candle to produce more soot will automatically be solved. 

And, just to be clear, a good quality candle doesn’t have to be super expensive. You just have to take the time to look at your options and find a candle that doesn’t have a ton of additives, has a good, cotton cored wick that isn’t too large, and is made of high-quality materials. Then you just have to burn your candle in a well-ventilated area without too many drafts, and you’ll likely have no problems with your candle jar turning black.

Melt the Entire Top of Your Candle Every Time

Beyond investing in a good quality candle that doesn’t have the characteristics that make it produce lots of soot, it is recommended that you burn your candle until the top is entirely liquid wax, if at all possible. 

Burning your candle until the top is completely liquid wax will help stop “memory rings” from forming in your candle. Memory rings are simply indented rings in the wax of your candle around the wick that will develop if you light your candle and don’t let it melt the wax to the edge of the container. Preventing your candle from having memory rings in its wax can help it to burn more efficiently and produce less soot.

Read more about Candle Tunneling: A Complete Guide (and fix it).

Care For and Trim Your Candle’s Wick

Trimming your candle’s wick and caring for your candle is also essential for combatting soot production. You don’t have to make it overly complicated, but merely taking a few minutes to clean, trim, and maintain your candle can make all the difference.

If your candle wick begins to mushroom (form black lumps towards the end of the wick) or becomes too long, it can start to produce much more soot than usual. To prevent this from happening, trim the wick down to about 1/4 inch. You should also regularly wipe any dust from the top of your candle and ensure there isn’t any dirt, wood, or other material on the top of your candle.

Read more about Why Should You Trim Your Candle Wicks.

Why Would You Want to Stop Your Candle Jar from Turning Black? Is It Harmful or Bad?

Wanting to prevent your candle jar from turning black from soot is purely an aesthetic choice. The black streaks on your candle’s jar can make it look dirty and make it stand out from the rest of the decor in your home. There are, however, no health concerns connected to the soot produced by candles.

As Candles.org writes, “the minuscule amount of soot produced by a candle is the natural byproduct of incomplete combustion…these everyday household sources of soot are not considered a health concern, and are chemically different from the soot formed by the burning of diesel fuel, coal, gasoline, etc.”

Put simply, the soot made by candles is not harmful and is in such small amounts that it is not considered bad in any way. The only reason you might want to get rid of it and prevent it from forming on your candles again is purely an aesthetic and personal choice. 

If you are fine with how soot looks on your candle jar, by all means, leave it there and keep on enjoying your candle!

Read more: 4 Ways to Put Out a Candle Without Black Smoke (Don’t Blow it Out!)

Grace Young

I love candles! I have personally tried over 100 brands of candles. The total burn time of these candles is over 5000 hours. I also talk about essential oil diffusers and reed diffusers. Essential oil diffusers and diffusers are also an important part of the scent in my home.

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