How Do Scented Candles Work? Here's The Answer

Imagine a quiet evening at home, the lights are dimmed and there's a single candle flickering, casting dancing shadows around the room while emitting a soft, warm glow. This simple scene has been recreated for centuries, ever since the first candles were invented. But behind this serene picture lies an intriguing combination of science and art. How does a candle produce light? What keeps it burning? How does it create scent?

In this blog post, we'll delve into the captivating world of candles, exploring the science behind their seemingly magical ability to transform a mere wick and wax into a source of light and warmth. So, whether you're a candle enthusiast or simply curious, join us as we illuminate the workings of these everyday marvels.

Understanding Scented Candles

Dive into the aromatic world of scented candles, uncovering their history, how they're made, and the science behind their soothing effects.


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When Was The First Scented Candle Created? A Journey Back in Time

The history of scented candles traces back thousands of years, intertwining with the evolution of civilizations and cultures. The ancient Egyptians are often credited with the creation of the first scented candles around 3,000 BC. They crafted torches by soaking the cores of reeds in melted animal fat, a rudimentary form of wax, and then coating them with a mixture of honey and cinnamon to create a pleasant aroma when burned.

Over time, the art of candle-making evolved, and other civilizations like the Romans and Greeks began using beeswax, a more refined and cleaner-burning material. However, it wasn't until the Middle Ages when the concept of scented candles as we know them today started to take shape. Monks in Europe began infusing candles with essential oils from herbs and flowers, creating a soothing aroma that enhanced their meditation practices.

Fast forward to the 19th century, advances in technology led to the development of paraffin wax, which became the standard for candle making up until recently, due to its affordability and ease of use. The modern scented candle industry didn’t really take off until the 20th century, paving the way for a global love affair with these aromatic delights. This industry is still growing and is predicted to for the forseeable future.

What Are Scented Candles?

At its most basic, a scented candle is a wax object embedded with a wick that, when lit, releases a fragrant aroma. But this simple definition belies the complexity and craftsmanship behind these beloved objects.


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A scented candle is composed of three main components - the wax, the wick, and the fragrance. The wax, usually made from paraffin, soy, coconut, or beeswax, forms the body of the candle. The wick, typically made from cotton, paper, wood, or metal, draws the wax towards the flame, enabling the candle to burn.

The fragrance is the soul of a scented candle. It's crafted from a blend of essential oils or synthetic aromatic compounds that are carefully selected and mixed to create a specific scent profile. When the candle is lit, the heat causes the fragrance oils in the wax to vaporize, releasing the scent into the air.

Scent Science: How Does A Candle Work?

The allure of scented candles goes beyond their warm glow and aesthetic appeal. There's a fascinating science behind how they work, particularly in the way they release their fragrant aromas.


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The Role of Heat in Scent Release

Heat plays a critical role in the release of fragrance from scented candles. When you light a candle, the heat from the flame melts the wax near the wick. This liquid wax is drawn up into the wick where the heat of the flame vaporizes the liquid wax, turning it into a hot gas.

It's at this point that the fragrance oils mixed into the wax also get vaporized. These vaporized molecules rise into the air, where they are detected by your nose as a pleasant aroma. Heat is thus essential for transforming the solid fragrance oils into a gaseous form that can be detected by our olfactory senses.

The Process of Combustion in Candles

Combustion is the scientific term for burning. In the context of a candle, combustion occurs when the wick is lit. The heat of the flame melts the wax around the wick, which is then drawn up by capillary action.

As the liquid wax travels up the wick, it gets heated further until it turns into a gas. When this gas comes into contact with the flame, it reacts with the oxygen in the air to create heat, light, water vapor, and carbon dioxide in a process known as complete combustion. It's this process that sustains the candle's flame and allows it to continue burning until all the wax (or fuel) is used up.

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Why Scented Candles Emit Aroma Even When Unlit

Have you ever noticed how a scented candle can still smell good even when it's not lit? This is because fragrance oils are volatile, meaning they can easily evaporate at room temperature.

Even when a candle isn't burning, some of the fragrance oil molecules in the wax are energetic enough to escape into the air. These airborne molecules then make their way to your nose, where they're detected as a scent. While this effect is more pronounced with heat (i.e., when the candle is lit), it can still happen to a lesser degree even when the candle is unlit.

The Sensory Experience of Scented Candles

Scented candles offer more than just light; they create a multi-sensory experience that can influence mood and evoke memories. Let's explore some of the intriguing aspects of this experience.

Why Scented Candles Smell Different When Burning vs. Not Burning

You may notice a difference in the aroma of a scented candle when it is burning compared to when it is not. This is primarily due to the heat that is involved when the candle is lit.

When you light a scented candle, the heat from the flame melts the wax and evaporates the fragrance oils, releasing them into the air as a gas. This process can alter the molecular structure of the fragrance oils, which may result in a slightly different scent compared to when the candle is unlit and at room temperature.

Additionally, when the candle is burning, the continuous heat allows for a constant release of scent, creating a more intense fragrance experience compared to the gentle diffusion of scent from an unlit candle.

The Soothing Effect of Scented Candles

The soothing effect of scented candles can be attributed to their combination of gentle light and pleasant aroma. The flickering light of a candle creates a calming atmosphere that can help reduce stress and promote relaxation.

Moreover, the specific scents used in candles can also have a soothing effect. For example, lavender is often associated with relaxation and sleep, while citrus scents are known for their invigorating and mood-boosting properties.

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How Our Brain Processes Scents

Our sense of smell is directly linked to the brain's limbic system, which is responsible for processing emotions and memories. When we inhale the aroma molecules from a scented candle, they trigger responses in this part of the brain.

For instance, certain scents can evoke specific memories or feelings. The scent of a beach-themed candle might trigger memories of a seaside vacation, while a cinnamon-scented candle might remind you of holiday celebrations. This powerful connection between scent and memory adds a unique dimension to the sensory experience of scented candles.


Common Questions About Scented Candles

Scented candles are a popular choice for creating a relaxing atmosphere and adding a lovely fragrance to your space. However, they also raise several questions for curious minds. Here are answers to some common inquiries.

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Do Scented Candles Have to Be Lit to Work?

Technically, no. Scented candles do not have to be lit to release their fragrance. The fragrance oils infused in the candle wax are volatile, meaning they can evaporate into the air at room temperature. Therefore, you can still smell a scented candle even when it is unlit.

However, the heat from a lit candle accelerates this evaporation process, making the fragrance more pronounced and widespread. So while an unlit scented candle can still give off a scent, a lit one will provide a more intense fragrance experience.

Why Don't Scented Candles Smell as Good When Burning?

Sometimes, scented candles may not smell as good when burning compared to when they are unlit. This could be due to a few reasons:

  1. Heat Alteration: The heat of the flame can alter the molecular structure of the fragrance oils, which may change the scent slightly. Some fragrances may not respond well to this alteration, leading to a different, sometimes less pleasant, smell.

  2. Poor-Quality Fragrance Oils: If a candle uses poor-quality or synthetic fragrance oils, these might produce an off or unpleasant smell when heated.

  3. Overpowering Scent: When a candle is lit, the scent is more intense due to continuous evaporation of fragrance oils. If the scent is very strong, it could become overpowering to some people when the candle is burning.

  4. Incomplete Combustion: In some cases, if the wick is too long or the flame is not burning properly, it can cause incomplete combustion. This might produce soot or an unpleasant smoky smell.


I think it’s safe to say that scented candles are more than just decorative items. They are a blend of science, art, and sensory experience that can transform your space and mood. From the chemistry of fragrance release to the soothing effect they provide, scented candles offer an intriguing intersection of science and sensation.

While they might raise some questions on how they work, understanding these aspects only enhances our appreciation of these delightful objects. Whether you're enjoying the subtle aroma from an unlit candle or basking in the intense fragrance of a burning one, there's no denying the allure of scented candles.