Understanding Candle Performance And Design Principles
The Anatomy Of A Candle
When I started a few years ago and ventured into the world of candle-making, selecting the proper wick became crucial for achieving an optimal burn during testing.
And it became a daily headache for a couple of years.
Making a candle is far more complex than diluting a perfume formula into a perfumer's alcohol. Not to diminish the extensive work that requires arriving at an optimal sillage and permanence on the skin, but the additional physics involved in the use of wax, a wick, and a vessel add different layers of complexity to the task of making a fragrance be diffusive and actually mean something.
Diameters Matter
The diameter and material of the candle vessel play a significant role in this process. And they can become another set of headaches during the creation process.
I learned that the wick size should be determined based on the radius of the container. All candle component distributors provide a spreadsheet with their recommended wick sizes, based on the diameter of the vessel to be used, which typically range from wick sizes 6, 8, 10, and so forth up to 22. Depending on the manufacturer, the numbers vary, and sometimes letters are added; however, the principle of thicker wicks having a higher code number remains the same. I've recently come across and started using a wick called Ultracore 3.0 in some limited-edition blends, which sounds like the name of an electric vehicle. An Ultracore wick is the last stop before resorting to more than one wick in your candle.
There are many wick compositions and manufacturers available. The expansion of the candle market has created a niche for multiple companies selling candle components. Over time, and after testing products from different companies, I settled on cotton wicks and a creamy coconut-soy hybrid wax that holds the amount of fragrance I prefer.
All my candles have a strong diffusion. I wouldn't spend money on a weak candle, so I wouldn't recommend or sell one that wouldn't diffuse throughout my entire house, including all three floors. For my bathrooms, I definitely like a strong candle. For the kitchen, foyer, and bedrooms as well. And, if I am lighting a candle in the living room "for mood only," it has to be smelled on the outdoor deck, at least.
Wick Size And Fragrance
Still, each of the recommended wick sizes may or may not work, depending on the complexity of the fragrance you use and the type of vessel, not only its diameter.
Get it now; why do they become a headache? This is where testing becomes a daily prayer. For me, it became a daily ritual during the Covid pandemic, and I have to thank those years for the handling I have over wicks today.
Through my blending and testing of hundreds of candles, I learned that the composition of a fragrance directly impacts the burning of the flame; it's simple physics: the heavier the ingredients, the thicker the wick should be. The wider a vessel, the denser a wick should be. This is a step that brand owners who don't blend their fragrances don't have to think about: the fragrance already comes premade. But I did not want to go that route; the fragrance is the most intrinsic part of my work, so why would I give it to someone else? And what about intellectual property?
Knowing I would deal with my fragrance creation, I realized that over time, I would gain a better understanding of the wick size, depending on the concentration of the materials used in the fragrance blends.
The thickness of the wicks may appear the same at first glance. Only through detailed examination and handling did I realize that some of them contained significantly more paper inside their waxed surfaces; I use 100% cotton wicks with a cotton core, and they come with their external surfaces pre-waxed, which protects the core from the heat of molten wax when pouring it. The hot, molten wax will instantly cause the wick to fall sideways without this protection.
Today, I can safely say that I can "feel" the density of a wick when I grab it. A size 12 and a size 14 will feel similar, but there is a difference in density between a size 12 and a size 22. No. Pun. Intended.
A complex woodsy and resinous fragrance may require a thicker wick, say 18 or 22. A light, citrusy blend could work well with sizes 12 to 16. Mind you, all these sizes are recommended for vessels with a diameter of approximately 3 inches. You can't pick one without testing it; it's as simple as that. Did you think a floral candle would be fine with a slim wick around 10, 12, or 14? Nope. If you use materials of natural origin, you will learn that floral oils and absolutes are among the thickest and densest materials you will work with.
What Happens When A Single Wick Doesn't Work
So, for a 3-inch diameter candle, you have many wick options if you, like me, are not a fan of multiple wicks. But what happens when you want to make larger candles?
You need more wicks.
A 4-inch diameter candle may require two wicks to help distribute heat evenly and ensure a more reliable burn. From there on, the wider the diameter, the more wicks you will need. However, having too many wicks can be a fire hazard. Sometimes, I see large vessels on the floor, with six or eight wicks, and they are shown stylized next to a sofa or a club chair. Sometimes, I see them displayed on top of books.
Hmmm...Candles and upholstery don't really get along. Flames and paper don't get along, either. Keep adding wicks, and you will expand your fragrance diffusion, alright, but also increase the risk of a fire that will consume not only your candle but your entire house. A profusion of wicks in a large container is a turn-off for me. I don't want to risk dropping something on it, and I don't want to have to have this giant candle by my side at all times; let's remember that a candle is also a source of heat. It can quickly become the most hated object in the room.
Wax And Wicks
The type of wax also affects the selection of wicks. For instance, soy or coconut wax candles typically require different wick types compared to paraffin wax. Soy waxes usually require thicker wicks. Which, in turn, may create more soot. None of the myths about soy wax being "cleaner" than this or that apply here: the simple fact is that soy requires more heat to diffuse. Therefore, you need a thicker wick. Paraffin wax may require slimmer wicks, but in turn, paraffin burns faster, reducing the lifespan of a candle.
Tunneling and Uneven Burning Issues
Tunneling occurs when the wick is unable to melt the surrounding wax effectively, typically due to an unsuitable wick size for the vessel. This not only diminishes the candle's lifespan but also can create an uneven burn pattern, producing soot and wasted wax. Once again, testing will dictate the size of the wick to avoid tunneling.
Tunneling can happen at any time with any candle. Other factors influence candle burning, such as the room's temperature or the presence of drafts. Sometimes, a properly selected wick will perform well in one candle but not in another of the same size, fragrance content, and wax. Each candle is unique after pouring. This may not be easy to understand, but a candle is a mix, a mixture of different ingredients, solidified at room temperature. This means that the contents are not entirely homogeneous. This means that the same candle you bought and lit for yourself in your living room may not perform as well for your best friend in her living room. Of course, a candle maker will standardize their production, but ultimately, when you start burning your candle at home, you will notice if it performs immediately or if it needs some adjustments.
This is why it is essential to follow instructions, such as trimming the wick, rotating it for an even burn, placing it away from windows or drafts, and ensuring the wick does not become slanted toward one side. Sometimes, using a candle warmer will fix some of the wick issues if you can live without the flame.
Optimizing Candle Burn: Time, Pool, and Soot Concerns
To ensure an optimal candle experience, it's essential to focus on the burn pool, minimize soot production, and maximize burn time. Each of these factors plays a critical role in achieving a clean, effective flame and enhancing your enjoyment of luxury candles.
Establishing an Ideal Burn Pool
Creating an ideal burn pool is crucial for achieving an even burn and preventing issues like tunneling. When you light a candle for the first time, allow it to burn until the wax pool reaches the edge of the container. This ensures that the entire top layer of wax melts evenly. Don't worry if some wax is left "glued" to the sides of the vessel during the first couple of burns. That corrects itself as the wax level goes down and more space is created at the top for more hot air to remain there during the next burns.
Ideally, you want to burn your candle until it reaches a full pool every time you burn it; that could be 2 or 3 hours each time you light the flame.
Regularly check the wick's position during use. If it shifts, re-center it while the wax is still soft. Following these steps not only enhances your candle's performance but also contributes to a more aesthetically pleasing wax pool.
Minimizing Soot and Smoke Production
To minimize soot and smoke, pay attention to wick maintenance and the quality of your materials. Always trim the wick to about 1/4 inch before each burn. This reduces carbon buildup and helps prevent soot from forming.
Sometimes, a wick needs to be trimmed before or during the first burn, for example, if the flame is higher than average. Consider an average height of 1 to 1.5 inches; if your flame is higher than that, blow the flame out, cut 1/8 inch off the wick, and relight. Continue watching the candle for optimal performance, turning it periodically to ensure an even melt, and be aware of drafts.
A well-maintained wick promotes a clean burn, reducing the likelihood of excessive smoke.
Selecting Luxury Candles
Selecting candles is a process that we learn over time. Before I became a maker, I enjoyed buying candles from various luxury brands, as well as some affordable brands priced under $40 each. I learned to distinguish between different types of vessels, waxes, and fragrances, which, in turn, helped me develop my brand.
Today, you may find many candle brands promoted as luxury. Luxury is an abstract concept that can mean different things. Luxury is not just the package or a name. And, beyond a certain level of wax and wick quality, what changes is the fragrance composition and the presentation. There are no such things as "luxury wax" or "luxury wicks"; they are mass-produced commodities available by the ton or by the thousands.
When I decided to work on my brand, I realized that the luxurious aspects would be the presentation and the fragrance composition because the materials used to make a candle or a diffuser are readily available on the market for anyone to purchase.
I use crystal vessels to pour my candles and use crystal also on my diffusers. Crystal offers light refraction and reflection that glass cannot, and it is the best representation of our core philosophy of transparency in everything we do.
Another aspect that I could include in the concept of luxury is the performance of my candles, as they are strong and have a high fragrance content, typically ranging from 10% to 12%. To me, a candle with a high ticket price should, no, must have a strong diffusion and be worth the price I paid.
Anytime you pick one of my candles, rest assured countless testing hours have gone into it, and the wick it has is the best choice for it, for its wax and for its fragrance type.
Oh, and the reason why I decided to blend my own fragrance formulas is a subject for another blog post.
RHR