Tag: Candles

Essentially, the candle has not changed much throughout history. It consists of a mass, generally a cylinder or block, of wax or other fuel with an embedded central wick that produces light when burned. Some candles may contain multiple wicks.

The term “wax” applies to a large group of chemically different materials or substances. They are typically composed of hydrocarbons, alcohols, fatty acids, and esters and are generally solid at ambient temperature, insoluble in water but soluble in nonpolar organic solvents, and have a melting point between 110°F to 200°F (approximately 43°C to 93°C).

There are a multitude of formulas and substances available under the name “wax,” and this amount continues to increase as chemists experiment with new chemical compositions. Waxes can be classified into two main groups: natural waxes and synthetic waxes. Natural waxes can further be divided into animal waxes, vegetable waxes, and mineral waxes. Animal waxes include beeswax, tallow, and animal-based stearin. Plant waxes include palm, carnauba, bayberry and soy. Mineral waxes can be further divided into fossil or earth waxes, which include ceresin and montan, and petroleum wax, which includes paraffin and microcrystalline. Synthetic wax consists of man-made materials and includes polymer waxes.

A wick is a strip or thread of fibrous or porous material that draws up the fuel (the wax) to the flame by capillary action. They come in a variety of material and thicknesses, depending on the desired result and the other components of the candle such as the wax type and size, fragrances, and colouring. There are hundred of types of wicks, but common materials include paper, flax, hemp, cotton, wood, and metal-cores such as zinc and lead.

Before going into the manufacturing process or how candles are made, it can be helpful to know how a candle works, or how it burns.

When a candle is lit, the heat from the flame melts the wax in and near the wick. This liquid wax is absorbed by the wick and is pulled upward in what is known as capillary action. Wax needs to be in a gaseous state for it to ignite and burn, and this happens when the wick traps the liquid wax in the heat of the flame, causing it to get hotter and hotter until it turns into gas. This wax vapour acts as fuel to keep the wick burning. The resulting heat travels in all directions.

Heat travels down the wick to melt more wax at the top of the candle. Hot wax vapours are drawn out from the wick and draw oxygen into the base of the flame. The hydrocarbons start to break down into molecules of hydrogen and carbon and then react with oxygen in the surrounding air to produce heat, light, water vapour, and carbon dioxide.

The chemical reaction in which the wax reacts with oxygen in the air is known as combustion, and it produces carbon dioxide and water in the form of steam.

The oxygen-rich base of the candle flame is characterized by a blue colour. The blue zone of the flame is where the oxygen enters and the hydrocarbon molecules begin to vaporize and separate. Surrounding the flame is a faint outside, called the veil, that is also blue because it directly meets with the oxygen of the air. It is also known as the outer zone and is where complete combustion of the wax takes place. This veil is the hottest part of the flame and reaches 1400°C, or 2552°F.

Above the blue zone of the base, directly above the wick, the flame has a dark or orange/brown region which has relatively little oxygen. This section, also known as the dark inner zone, consists of unburnt wax vapours. Soot (small, hardened carbon particles) begins to form as carbon continues to break down. The soot is not harmful if it burns up before leaving the flame. It is these carbon particles that create the dark colour. This zone emits the least heat.

The next zone is the yellow zone, also known as the luminous zone. It consists of partial combustion (insufficient oxygen is available to completely burn all of the wax vapour) and is moderately hot. The carbon particles increase and then rise, where they heat until they ignite. The perceived colour is due to the ignition of the carbon particles. As they are heated, they glow or become “yellow-hot” in what is known as incandescence. They emit the full spectrum of visible light, but it is the yellow portion that is the most dominant.

The process of the wax being heated and then drawn up the wick, where it vaporizes and combines with oxygen in the air to combust, or burn, continues to repeat until all the wax has been burned or the heat has been eliminated. The combustion process may also take a few minutes after the candle has been lighted in order to stabilize.

This combustion process of a candle can be very efficient, but it isn’t perfect. All candles produce soot and smoke due to incomplete combustion. Insufficient oxygen is available to fully combust the soot particles, and some escape. This soot and smoke come from the bright yellow zone of the flame. If sufficient oxygen were available, then there would be no soot. Only carbon dioxide and water would be produced, and the entire flame would be blue.

The exact colour can indicate the temperature, the type of fuel, and the type of combustion taking place. Blue indicates complete combustion, such as in the case of a gas burner, while yellow indicates incomplete combustion, like in a candle flame.

In the next blog post of this series, we will begin to look into the general candle manufacturing process, starting with the preparation of the wick.

There is no recorded history of candle making, so the exact origin of candles is not known. It is believed that the first candle may have consisted of dried branches being dipped in animal fat. When lighted, it produced a slow-burn and reliable source of light. References to the use of candles in the Bible and depictions of the use of candles in ancient Egyptian reliefs reveal that candles have been around for thousands of years, and have served many purposes, from lighting homes, aiding travellers or providing a source of light during the night, to measuring time and playing a role in religious ceremonies.

Candles have been used in many cultures and have been created with a variety of material over the years.

Roman candles were made by dipping rolled papyrus repeatedly in melted tallow (animal fat) or beeswax; early Chinese candles were moulded in paper tubes, using rolled rice paper for a wick, and wax from certain insects combined with seeds from various trees; early Japanese candles were made of wax extracted from tree nuts; in India, where the use of animal fat in candles was prohibited by religious decree, candles were made from the wax skimmed by boiling the fruit of the cinnamon tree; and in Colonial America, women produced a sweet-smelling wax by boiling the greyish green berries of bayberry bushes.

Beeswax was introduced in the Middle Ages as a form of candle wax. It burned clean and pure and emitted a pleasant odour, unlike the foul, acrid odour of tallow or other animal matter. However, it was expensive, so its use at the time was limited to the wealthy and the church.

In the 18th century, spermaceti became available in quantity due the growth of the whaling industry, and became another popular source of wax for candles. Spermaceti is a white, waxy substance obtained by crystallizing sperm whale oil. It is used for making candles, ointments, and cosmetics. This wax was found to produce no repugnant odour when burned and was harder than both tallow and beeswax.

Major developments in candle making occurred during the 19th century. During this time, French chemist Michel Eugene Chevreul discovered how to extract stearic acid from animal fatty acids, leading to the development of stearin wax. Inventor Joseph Morgan developed the first mass-production candle making machine; and chemists learned how to separate the thick, dark waxy substance from petroleum and refine it to create what is known as paraffin wax. This paraffin wax was found to be relatively hard and lacking in odour and colour. It remains one of the most commonly used candle waxes in the world.

Paraffin was eventually blended with other substances to create a more durable wax. These substances included spermaceti and ceresin, a type of mineral wax. Paraffin and microcrystalline wax (a type of wax that has a darker colour, finer crystals, and generally higher melting point than paraffin) are derived from petroleum, while ceresin, ozokerite, and montan wax are mineral waxes derived from coal and shale. Paraffin wax is sometimes used as an umbrella term for a variety of formulas involving paraffin or similar types of chemicals and waxes.

Candles were no longer needed as a light source after the introduction of the incandescent light bulb in 1879, and their popularity began to decline. They experienced a surge of popularity again in the 20th century when the availability of petroleum byproducts such as paraffin increased due to the growth of U.S. oil and meatpacking industries, and consumers had an increased interest in candles as a decorative item. To meet growing demands and to improve performance and cost, candle makers experimented with new wax blends.

Soy wax candles in particular are a rather recent invention. Michael Richards is widely credited for bringing the first soy wax candles to the market when, in 1991, he noticed a growing demand for natural wax candles and began experimenting with a range of plant waxes and vegetable oils, including beeswax, partially hydrogenated soy oil, coconut oil, palm oil, and almond oil. Natural waxes such as pure beeswax was (and still is) expensive, and he wanted to find a wax that could be cost-competitive with paraffin wax. In 1996, the soy wax candle became available to the general public.

The innovation with candle making still continues. The flicker of a candle flame elicits endless fascination, and scientists around the world have studied and conducted experiments on candles to learn about how they burn – their flames, emissions, and combustion – including how a candle flame behaves in microgravity.

Chemists still experiment with new types of waxes, wax blends, and fragrances to create candles that match different performance needs and are sustainable and low cost to manufacture. They aim to find a candle that burns cleaner, longer, and with a pleasant aesthetic and aroma. This experimentation has resulted in candles that come in a variety of materials, sizes, shapes, colours and scents.

Candles are seen as appropriate gifts for holidays, house-warming gifts, thank you gifts, adult birthday gifts, and more and are currently used for celebrations, such as birthdays; religious ceremonies, rituals, or occasions such as praying, grieving, celebrating, or meditating; and creating atmosphere or mood during dinners and other occasions. A candle can be symbolic for life and hope.

Candles can help relieve stress, create a warm, comfortable feeling, and disguise other scents or odours. Some individuals use candles as a light source in emergency situations, though that is generally not recommended due to the risk of fire. Others may simply use a candle as a piece of decor, to add beauty to a room.

A candle may seem simple, and yet it is deeply involved in culture, has served many vital functions throughout the years, and can touch our soul. The creation of the candle also seems simple, but it is an intricate science.

In the next blog, we will look into what a candle is and how it burns, and then in following blogs we will go into the different types of wicks, waxes, fragrances and colourants to help us choose a candle that is better for needs and our health.