Scent Science: Why Does My Fragrance Smell Differently in Candles and Soaps?

Have you ever wondered why your favourite fragrance oil smells bold and cozy in a candle, but complete different in soap? Your nose isn't playing tricks on you. Just like us, fragrance oils react differently to their environment, transforming in unexpected ways.

That's right, it's time for another LARK science lesson. Let's break down some of the key factors affecting your fragrance's mood.

 HEAT + BURN VS. COLD + WASH 

Candles and soaps undergo completely different processes to release fragrance.

When you burn a candle, heat from the flame vaporizes the fragrance oil, releasing it into the air. You're smelling the fragrance in its warm, diffused state. Heat also affects scent notes differently. Vanilla, ambers, and spices are amplified, while delicate florals and bright citruses become muted.

With soap, fragrance oil is released through lathering and skin contact. You're exposed to the scent in a cool, wet environment. Top notes may become stronger, while deeper base notes get lost.

 COMING BACK TO CHEMISTRY 

Fragrance oils don't sit idly in your product. They interact with their surroundings.

The type of wax you use plays a major role in how fragrance is thrown from your candle. For example, soy wax holds fragrance differently than paraffin, sometimes muting or altering certain scent notes. The size of your wick and the temperature of the burn can also affect how a scent develops over time.

The pH level of soap, especially in cold and hot process methods, can lead to fragrance oils morphing and fading in unexpected ways. Have you had a bright citrus transform into something weirdly herbal and vegetal? That's pH for you.

 EVAPORATION + LONGEVITY 

Just like humans, some scent notes are naturally more volatile. In the world of fragrance, this means they evaporate faster than others.

Fragrance is released slowly from a candle as heat melts wax. Top notes evaporate first, followed by middle and base notes, creating a layered scent experience.

Exposure to water speeds up fragrance release from soap. You may get a strong initial scent from lathering that disappears or changes as delicate top notes are rinsed away.

 FRAGRANCE LOAD + CONCENTRATION 

Different products require different amounts of fragrance oil to work effectively.

Candles typically hold 6–12% fragrance oil, varying depending on the type of wax used. High quality candles are formulated to throw scent well while burning.

Soaps usually hold 3–6% fragrance oil. Skin and safety considerations, as well as the ability of excess oil to cause discolouration, acceleration, or separation, are the reason for this smaller percentage.

 THE INFLUENCE OF INGREDIENTS 

Additional ingredients in your product formula can affect how fragrance is experienced. Wax type, dyes, wicks, and even the vessel of a candle can impact its scent throw. Butters, clays, milks, and natural additives like honey can modify the release of fragrance from soap.

If you plan on using the same fragrance oil across multiple applications, here are a few strategies to help you out:

 01  Test product formulas in small batches before committing to large pours. In our experience, you can always add more oil but you can't take oil away once poured.

 02  Adjust your expectations. We've all heard that one before right? Some fragrances are rockstars in wax but struggle in soap. Some fragrances are bathing beauties, but don't love the heat. All are beautiful and deserve their time to shine.

 03  Blend strategically. Sometimes, tweaking a scent with complementary notes can help a fragrance shine across different mediums.

Thanks for participating in today's science lesson, maker! Have we told you you're our favourite student?