What Is The Black Stuff On Candle Wicks?

Candles create a cozy ambiance in any space and many enjoy the soothing flicker of the flame. But sometimes you may notice a black substance on the tip of the wick. This unsightly “mushroom cap” can be disturbing and raise concerns about safety. So what causes this strange soot buildup?

This comprehensive guide will uncover everything you need to know about the black stuff on candle wicks. We’ll start by examining the materials that make up the wick and why it burns. You’ll learn what specifically creates that black carbon deposit, how it forms, and whether it poses any health risks. We’ll also provide tips on preventing soot, removing existing residue, proper wick care and maintenance.

By the end of this piece, you’ll have a full understanding of this candle curiosity so you can enjoy your favorite scented and decorative candles with confidence.

What is the Wick Made of?

The wick is a specially designed strand at the center of the candle. Wicks are typically made from thin strands of cotton, paper, or wood-based fibers that are braided or twisted together (https://candles.org/elements-of-a-candle/wicks/). The most common materials used are:

• Cotton – Cotton is a soft, fluffy material that makes an excellent wick. It burns evenly and doesn’t produce much soot.
• Paper – Paper wicks are stiff and sturdy. They tend to be very affordable.
• Wood – Wooden wicks are made from thin strands of wood woven together. They burn slowly and evenly.

The wick material is chosen based on how slowly and steadily it burns. A high quality wick will burn from tip to base without bending, flickering excessively, or leaving residue. The thickness and weave of the wick strands impacts the capillary action that draws fuel up to the flame. A well-designed wick is essential for proper candle performance.

Why Does the Wick Burn?

The wick is a specially designed component that enables a candle to burn. According to HowStuffWorks (https://home.howstuffworks.com/question267.htm), the wick draws up liquid wax via capillary action and brings it close to the flame where it can vaporize. This creates a “fuel supply” effect where the wick acts like a fuel pump to deliver wax to the flame. As the liquefied wax reaches the flame, it vaporizes into a gas which then ignites and combusts.

Candles.org (https://candles.org/elements-of-a-candle/wicks/) explains that because wax in its solid form will not burn, the wick is necessary to raise the melted wax to the flame and allow combustion to occur. The wax vaporizes due to the heat of the flame, and it is this wax vapor that actually burns to produce the candle’s flame. Without the wicking action transporting liquefied wax upward, there would be no fuel to keep the flame going.

What Causes the Black Stuff?

The black stuff on candle wicks is commonly referred to as soot. Soot is composed of unburned carbon particles that are released during the incomplete combustion of the candle wax and wick [1]. When a candle burns, the heat from the flame melts the wax which is then drawn up the wick via capillary action. As the liquid wax reaches the flame, it vaporizes and undergoes combustion. During this combustion process, the hydrocarbon molecules in the wax break down and react with oxygen to produce carbon dioxide, water vapor, heat, and light. However, incomplete combustion can occur if there is insufficient oxygen, the wick is too large, or there are contaminants present. This incomplete combustion results in some of the carbon atoms failing to fully oxidize, producing unburned carbon in the form of soot [2].

As the candle continues to burn, these unburned carbon particles are carried up into the flame where some will be combusted, while the remainder will escape the flame and accumulate on the wick as black soot. Over time, this buildup of soot on the wick can become quite substantial if the conditions for incomplete combustion persist.

Is the Soot Harmful?

The soot produced by candle wicks burning is generally not hazardous in small amounts. According to https://candles.org/4-common-candle-myths-debunked/, the small amount of soot produced by a candle is a natural byproduct of incomplete combustion and is not considered dangerous. However, the soot can trigger asthma or allergies in some sensitive people.

As noted by https://www.healthline.com/health/are-candles-bad-for-you, breathing too much of any smoke may potentially damage health. People with asthma or breathing sensitivities should take precautions when burning candles, as the soot may aggravate their condition.

Overall, candle soot is generally safe in moderation for most people. But those with sensitivities should be cautious and ensure proper ventilation when burning candles.

How to Prevent Soot Buildup

One of the best ways to prevent soot buildup on your candles is to properly trim the wick before lighting. Industry experts recommend trimming the wick to 1⁄4 inch before the first use to reduce excess carbon buildup and sooting [1]. This prevents the wick from producing a large flame and creating smoke. You’ll get a cleaner burn by starting with a shorter wick.

It’s also important to make sure the wick is centered in the melted wax pool as the candle burns down. If the wick leans too far to one side, it can start to smoke and sputter. Gently straighten the wick periodically to keep it upright. Using a wick bar can help center the wick in votives and containers.

Additionally, choose a lead-free wick to avoid heavy soot production. Lead-core wicks release more carbon as they burn and create more smoke and soot. Lead-free cotton or paper wicks produce less soot. Carefully follow the manufacturer’s recommendations for proper wick sizing.

Removing Existing Soot

Before attempting to remove soot stains, it’s crucial to let the candle cool completely. Trying to clean off soot while wax is still warm can lead to the stain spreading and becoming more difficult to remove. Wait at least a couple hours after blowing out the candle before cleaning.

To remove soot stains, start by using warm water and a mild soap. Dish soap or laundry detergent work well. Dampen a soft microfiber cloth in the soapy water, then gently rub the stained area. Avoid using excessive pressure or friction, as this can abrade the surface. Work the cloth in circular motions to lift the stain.

For more stubborn stains, a small amount of baking soda can be added to the soapy water for extra cleaning power. Let the baking soda solution sit for 5-10 minutes before wiping away. Vinegar can also help cut through wax residue.

With patience and gentle agitation, soot stains should come clean. For wicks themselves, trim off the charred ends regularly to discourage soot buildup.

When to Trim the Wick

It is recommended to trim the wick every few hours of burn time to prevent excess soot and mushrooming. According to Harlem Candle Company, you should trim the wick at least every 4 hours of burn time for an optimal experience.

You should also trim the wick whenever you notice it mushrooming or producing excess soot, as this can lead to uneven burning, tunneling, and smoke. Trimming helps maintain an even flame. As Martha Stewart recommends, approach the wick from the top and cut it vertically to about 1⁄4 inch in length, which is considered optimal.

Trimming the wick regularly prevents the buildup of excess carbon deposits and allows for a cleaner burn. This helps maximize the life of your candle and fragrance throw. A neatly trimmed wick supported by a melted wax pool is key for candle care.

Proper Wick Size

Matching the proper wick size to your candle diameter is crucial for optimal candle performance. As a general rule, bigger candle diameters need bigger wick sizes. Using a wick that is too small for the candle diameter will prevent the melt pool from reaching the edges of the container as the wax melts. On the other hand, a wick that is too large can create overly large flames and soot issues.

According to CandleScience, a good starting point is to use the following wick sizes based on candle diameter:

• Less than 2″ diameter – CD 4, CD 6, or CD 8 wicks
• 2-3″ diameter – CD 10, CD 12, or CD 14 wicks
• 3-4″ diameter – CD 16 or CD 18 wicks
• Over 4″ diameter – CD 20 wicks

However, wick sizes should be tested with the specific wax, fragrance, and vessel being used before mass production. Wick performance can vary based on these factors. Testing is the only way to dial in the perfect wick for each candle.

Conclusion

In recap, the black substance that forms on candle wicks is unburned carbon, also known as soot. This soot is a natural byproduct of the combustion process as the wick burns. Proper wick maintenance, such as trimming the wick to 1⁄4” before each lighting, helps maximize full wick combustion and prevents excess soot production. As long as the candle is burned safely by keeping it away from flammable objects and not leaving it unattended, the small amount of soot produced leaves behind no safety concerns.

With a basic understanding of wick composition, the combustion process, and proper wick maintenance, candle enthusiasts can continue enjoying their favorite scented and decorative candles worry-free. The occasional trimming and checking of wick length will help reduce messy soot buildup and keep those candle flames gently glowing.