The purpose of a wick is to deliver fuel (wax) to the flame. Acting like a fuel pump, the wick draws the liquefied wax up into the flame to burn. Different wick sizes allow for different amounts of fuel to be drawn into the flame. Too much fuel and the flame will flare and soot; too little fuel and the flame will sputter out.
All wicks consist of a bundle of fibers that are twisted, braided or knitted together. These fibers absorb the liquefied wax and carry it to the flame by capillary action.
There are literally hundreds of different styles and sizes of wicks. The type of wax used in a candle, as well as the candle’s size, shape, color and fragrance materials all impact wick choice. Selecting the correct wick is critical to making a candle that burns cleanly and properly. Reputable candle manufacturers take great care in selecting a wick of the proper size, shape and material to meet the burn requirements of a particular candle.
Types of Wicks
Most high-quality wicks are made from braided, plaited or knitted fibers to encourage a slow and consistent burn. In general, twisted wicks are of lower quality than braided or knitted wicks. They burn much faster because their loose construction allows more fuel to quickly reach the flame. However, twisted wicks are useful for certain applications, such as birthday candles.
In general, wicks can be divided into four major types:
Flat Wicks. These flat-plaited or knitted wicks, usually made from three bundles of fiber, are very consistent in their burning and curl in the flame for a self-trimming effect. They are the most commonly used wicks, and are often found in taper and pillar candles.
Square Wicks. These braided or knitted wicks also curl in the flame, but are more rounded and a bit more robust than flat wicks. They are preferred for beeswax applications and can help inhibit clogging of the wick, which can occur with certain types of wax formulations, pigments or fragrances.
Cored Wicks. These braided or knitted wicks use a core material to keep the wick straight or upright while burning. The wicks have a round cross section, and the use of different core materials provides a range of stiffness effects. The most common core materials for wicks are cotton, paper, zinc or tin. Cored wicks can be found in jar candles, pillars, votives and devotional lights.
Specialty Wicks. These wicks are specially designed to meet the burn characteristics of specific candle applications, such as oil lamps and insect-repelling candles.
Wick Use in the U.S.
Found primarily in inexpensive foreign candle imports, lead wicks were banned from the U.S marketplace in 2003. NCA-member manufacturers voluntarily discontinued the use of lead wicks in the mid-1970s, and in 2000, asked all U.S. candle manufacturers to join its members in signing a formal pledge to do the same.
The metal-core wicks sometimes found in candles are typically zinc- or tin-core wicks. They are most often used in container candles and votives to keep the wick upright when the surrounding wax liquefies. Scientific studies have repeatedly shown both zinc- and tin-core wicks to be safe.