Candle Wicks: How They're Made & How They Work

close up of a candle wick

Whether they're setting a relaxing mood or restoring a kitchen’s aroma after a particularly disastrous attempt at emulating Gordon Ramsay, candles can be an important part of any household’s repertoire.

At first glance, the various colors, smells, and shapes of candle waxes can obscure the star of the show: the wick. The wick, more than just the object being burned, is the component that can determine the speed at which the candle burns, the heat of the flame, the cleanliness of the burn, and even the sound of the candle.

Given this importance, how wicks are made and how they work are crucial to understanding the candle.

Brief History of Wicks

The story of the wick naturally follows the story of the candle. Technically, the first “candles” were rushlights (reeds soaked in animal fat) used in Ancient Egypt. The first candle wax and wick combo is generally attributed to the Romans, as they used rolled papyrus (paper) dipped in tallow (animal fat) or beeswax. Similar forms of this were used all over the world with variations in the type of wax and wick being used.

One of the largest developments in candle making occurred with the wick. Leading up to this development, different fibers began to replace rushes and reeds until 1824, when Jean-Jacques Cambaraceres developed the plaited wick. Not long after, in 1834, Joseph Morgan invented a candle-making machine capable of mass production. With this historical context in mind, it is no wonder that there are now various types of wicks, all with their own distinct properties.

How Wicks Work

How a wick actually works is pretty fascinating. Instead of just burning, such as logs in a fireplace, the wick acts as a pipe, siphoning up the fuel to be burned.

This is working through a scientific principle called “capillary action.” This involves the surface tension, cohesion, and adhesion of the liquid in question (in this case, the melted wax and fuel). Essentially, the adhesion to the wick material pulls liquid molecules up while the surface tension and cohesion between the liquid molecules brings as much of the liquid up as gravity allows. This can be seen when a paper towel is dipped into water and the water runs up the towel or how plants absorb water through their roots.

Different candle wicks all have different effects on the capillary action of the fuel, meaning that some wicks pull up more or less of the fuel. This can affect the size of the flame, the temperature of the flame, and the rate at which it burns. In some cases, too much fuel can cause the flame to flare up and soot whereas too little fuel will let the flame die out. 

In addition to the amount of fuel, certain wicks can lead to buildups of wax at the end of the wick, causing “mushrooming.” This can be a result of choosing the incorrect wick, wick size, or wax combination. This is related to “curling,” where certain wicks tend to self-trim by curling down as they are burned, keeping the top of the wick close to the hottest part of the flame. To avoid mushrooming, it is essential to find the right kind of wick for your candle.

Types of Wicks

For most candle wicks, how they are made is evident in their name and shape. While most can still be made by hand, such as braided wicks and wooden wicks, most are now made by specialized machines. Here are a few types of wicks:

  • Flat Wicks:

  • One of the most common types of wicks, flat wicks are usually made from three bundles of braided or plaited fibers, such as cotton. Shaped like small, flat straps, similar in shape to those on backpacks or purses, flat wicks are made to curl when they are burned. These are typically used on taper and pillar candles.

  • Square Wicks:

  • These wicks are braided from fibers, just like flat wicks, except these have a more round and robust shape, allowing them to stand upright longer. These are also great for pillar candles, but because they don't curl as easily, some trimming might be involved. 

  • Cored Wicks:

  • These wicks involve a fibrous outside along with a studier core, such as zinc or cotton. The benefit of these comes in the candle making process. Because they can stand upright by themselves, you do not need to suspend the wicks during a pour or dip process, making them great for container candles. However, since they are sturdy, they are predisposed to mushrooming and therefore involve much trimming.

  • Wooden Wicks:

  • These wicks are obviously made from wood, providing a low, even burn and a nice crackling sound like campfires. Despite their simple sounding name, they can come in a variety of shapes and sizes. Since they are pretty sturdy, they also need to be trimmed. 

  • Specialty Wicks:

  • While this list cannot be exhaustive, this category is something of a catch-all. These specialty wicks are wicks that are designed for specific candles, such as insect-repellent or oil lamps.

    So if you plan to restore your kitchen’s aroma to its former glory, be sure to consider the exciting complexity of candle wicks.