Fragrance from a candle comes from the fragrance molecules in the candle wax being bounced off into the air. To better understand this process, let’s look at some of the principles of evaporation.
Everything we see and touch is made up of atoms and molecules. They are in constant motion, bumping and bouncing off of each other. Atoms and molecules that are at the surface of a liquid can get bumped off into the air. This process is commonly known as evaporation.
Evaporation depends on the weight of the molecules, their density, and the bond or attraction of the molecules to each other. When a liquid evaporates, its molecules must separate themselves from their attachment with others in the liquid and then move off into the air space above.
Nevertheless, the molecules in some kinds of liquids, like oil for example, are rather large and attached to each other. This means that evaporation, if it occurs at all, is very slow. That is why cooking oil, even though sometimes heated to a very high temperature, does not evaporate to an appreciable extent.
Paraffin wax, typically (C25H52) molecules by themselves do not evaporate easily because of their weight, density, and adhesion to each other.
The amount of molecules escaping into the air also depends on how much surface area of the liquid is exposed to the air. Evaporation of water molecules is the easiest to understand because we evidence this happening all the time. Ice will evaporate but at a much slower rate than water at room temperature – there is less molecular energy at colder temperatures, but ice will evaporate. If a cookie sheet has the same amount of water on it that is in a glass of water, which will evaporate faster? That’s right!…The cookie sheet, because there is more surface area of water on the cookie sheet exposed to the air.
Now if you heat the liquid and give the molecules more energy, the rate of
evaporation will increase. Heating the liquid makes the
molecules move faster and weakens their attachment to each other. If you increase the energy by heating the liquid, the molecules have a better chance to get bumped off into the air. Typically the fragrance molecules in the wax of a candle weigh less than the hydrocarbon molecules of the wax and have a better chance to escape into the air.
If there is an air flow over the liquid, there is more of a chance for the molecules at the surface to be drawn into the air.
Strength of Fragrance
Fragrance used in candles is typically made from either natural essential oils, or man made synthetic fragrant compounds, or a combination of both essential and synthetic. With the concern we all have about using “Natural” and “Renewable” resources, more fragrance companies have been bombarded with requests for essential oils. Most natural, essential oils can be very expensive and can lack the strength or “throw” that some of the man made compounds have. It is the challenge of the candle manufacturer to meet the demand for natural products, provide their customers with the fragrance they expect and keep it affordable.
So, when you burn a candle, the flame is constantly heating the melted fragrant wax. The liquid wax moves out from the flame over the top of the liquid wax and back again under the warmer wax. This creates a melted pool of wax around the flame and increases in size until the maximum pool diameter is reached. This liquid pool of wax contains the fragrance molecules bouncing around and getting thrown off into the air. The diameter of the liquid pool is determined by the flame size and the melting temperature of the wax. The flame serves a second purpose. It warms the air around itself and and helps draws the fragrance molecules from the liquid wax. The heated air rises and carries the fragrance into the room.
There are many candle and fragrance products available in today’s market, including wax tart melters, both electric and tealight warmers, jar warmers, plug in warmers and diffusers with so many designs, shapes and sizes. These products have had quite an impact in the retail candle market.
Why are candles themselves still so popular? A candle not only provides fragrance, but also the romantic ambiance creating atmosphere desired by so many. Not only does a candle offer ambiance, but when used for fragrance, it encompasses all the categories for getting the “Most Fragrance From Your Candle”. The flame heats the wax, a larger candle will create a larger surface area of fragrant wax, and the flame provides a warm current of air flow pushing the fragrance into your room. Strength of Fragrance is determined by the candle company’s experience and the quality of the fragrance supplier. We have had over 40 years of experience in the candle business and we have 16 quality fragrance suppliers.
Jar candles have been the most popular fragrance producers in the past several years. People like the fact that the wax is in a container which reduces the chance of spilled wax. They also can liquefy more wax resulting in more fragrance. Our 64 Oz Jars have become one of our biggest sellers. The surface area of wax is more than 3 times that of a 22 or 26 Oz jar. Our customers call these “Whole House Fragrancers”
When you buy a candle for fragrance, consider the 4 categories discussed above.