The Science Behind Reed Diffusers

The Science Behind Reed Diffusers

Reed diffusers are a great way to scent a space and can often be a better choice than candles. They are also a lot more discreet.

reed diffuser has a container filled with scented oil and special reeds that absorb the oil. The reeds slowly release the scent through capillary action over time.


A reed diffuser’s reed sticks act as porous wicks, drawing scented oil from a container and dispersing it into the air through capillary action. The oil is usually derived from natural ingredients like essential oils or synthetic fragrances. Compared to traditional room sprays and candles, reed diffusers are generally considered a safer, healthier option since they don’t release harmful chemicals into the air.

The type of fragrance you choose will also influence how the scent travels throughout your space. For instance, if you want the room to smell clean and fresh, opt for citrusy, floral, or fruity scents. Try earthy, woody, or spicy scents for those who prefer a warm and inviting atmosphere. Often, these scents are housed in sleek bottles that can enhance the look of your space and complement your home’s decor aesthetic.

The stick’s thickness is another important aspect to consider when choosing a reed diffuser. Thicker reeds will absorb more oil and diffuse it faster but may require more frequent flipping. In general, thinner reeds are better for longer-lasting and consistent evaporation.

Many reed diffusers feature a matching fragrance as a candle, wax melt, or an air-freshening room spray for an all-in-one product that can freshen your entire space. This is a convenient way to create an integrated and cohesive design for your home. Regardless of your design, look for a container that can be refilled. Ideally, it should hold at least one full bottle of your scented oil.

Capillary Action

The way that a reed diffuser works has less to do with evaporation and more to do with capillary action, the process by which liquids rise in porous materials. This happens when the forces of adhesion are greater than the forces of cohesion so that a liquid can draw itself up against its surface tension. This principle allows fountain pens to wick ink from the reservoir into the nib, which is why some aquatic insects can walk on water.

The height to which a reed diffuser can rise depends on its size and the thickness of the reeds. Thicker reeds are more effective at lifting fragrance oil but can also oversaturate and overwhelm a space with too much of a good thing. Look for reed diffusers with thin reeds or consider a different type of reed, like fiber reeds, made from a mixture of terylene and cotton and have a uniform porosity that makes them ideal for oil wicking.

The Scent

A reed diffuser’s main components are a container, reed sticks, and oil. The container is typically made from glass to prevent spills and contains a plain liquid or a special blend of fragrance oils. The reeds are then placed into the bottle so that one end is submerged in the liquid and the other is exposed to the air. The reeds act as channels for the oil to travel up, releasing the scent into the air as it moves along the reeds’ porous surfaces.

The light and volatile molecules of the scented oils in the reed diffuser liquid are attracted to the reeds’ surface, so you must choose a high-quality reed. The reeds are designed to absorb the oil and release it into the air slowly through a process known as capillary action. The reeds’ surface also helps control how much and how fast the oil is released into the air, giving you more or less fragrance control.

The temperature and humidity of the room where you place your reed diffuser can impact the fragrance strength, as the oils will evaporate faster in warmer and more humid environments. It’s also recommended that you flip the reeds over every few weeks to encourage even scent distribution and keep them from becoming clogged with oil particles.

The Convenience

Reed diffusers continuously fill a room with their fragrance, unlike other home fragrance products like scented candles that only function when lit. They also require no electrical power and are a safer alternative to flame-based home fragrances as they don’t produce heat or potentially dangerous aerosols.

A reed diffuser typically consists of three components: a bottle with a scented liquid, a set of reeds, and the reed diffuser vessel. The liquid is usually diluted with a carrier oil, such as fractionated coconut or sweet almond oil, to help the scent soak up the reeds and diffuse into the air. Fragrance oils are often alcohol-based, increasing their volatility and helping the scent travel farther. However, some reed diffusers are also available in alcohol-free formulations, slowing the evaporation process and making the scent last longer.

Using a reed diffuser is simple: Uncap the bottle (reed diffusers come prefilled with oil, but you can use your oil in a separate bottle) and add the included reeds. Allow the reeds to soak up the oil, then flip them occasionally to encourage the even diffusion of scent throughout the room.

Choose from a range of reed diffuser fragrances to suit any decor or mood. From calming lavender and jasmine to cozy cedarwood and patchouli, every season has a scent. Try an autumnal blend of cinnamon and apples or a wintery mix of blue cypress, juniper berries, and smoked vanilla bean to give your home a festive feel.

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