Why Your Fragrance Oils Smell Different in Candles vs. Soaps
Have you ever fallen in love with a fragrance oil in a candle, only to try it in soap and think, wait… this isn’t the same? You’re not imagining things. Fragrance oils can behave very differently depending on how they’re used, and there are a few key reasons why.
1. Heat & Burn vs. Cold & Wash
Candles and soaps go through completely different processes when it comes to fragrance release.
Candles: When you burn a candle, the heat from the flame vaporizes the fragrance oil, releasing it into the air. This means you’re smelling the fragrance in its warm, diffused state. Heat can amplify certain notes (like vanillas, ambers, and spices) while muting others (delicate florals and bright citruses).
Soaps: In soap, fragrance oil is absorbed into the formula and released through lathering and skin contact. This means you’re smelling it in a cool, wet environment rather than a heated, airborne one. Some top notes may come through stronger, while deeper base notes can get lost in the mix.
2. The Chemistry of It All
Fragrance oils don’t just sit idly in your product, they interact with their surroundings.
Candles: The type of wax you use plays a major role in how fragrance is thrown. Soy wax, for example, holds onto fragrance differently than paraffin, sometimes muting or altering certain notes. Wick size and burn temperature can also impact how a scent develops over time.
Soaps: The pH level of soap, especially in cold process and hot process methods, can actually change the fragrance. Some oils morph, fade, or even react in unexpected ways. Ever had a bright citrus turn into something weirdly herbal? That’s the high pH at work.
3. Evaporation & Longevity
Some fragrance notes are naturally more volatile, meaning they evaporate faster than others.
In candles: Fragrances are slowly released over time as the wax melts, with the top notes evaporating first, followed by the mid and base notes. This creates a layered scent experience.
In soap: Water exposure speeds up evaporation, meaning you might get a strong initial scent while lathering, but some of those delicate top notes fade quickly once rinsed away.
4. Fragrance Load & Concentration
Different products require different fragrance percentages to work effectively.
Candles typically hold between 6-12% fragrance oil (depending on the wax). A high-quality candle is formulated to throw scent well while burning.
Soaps, on the other hand, usually contain 3-6% fragrance oil due to skin safety considerations and the fact that excess fragrance can cause issues like discolouration, acceleration, or separation.
If you’re using the same fragrance in both, but one smells much stronger, it’s likely due to the difference in concentration.
5. The Sneaky Influence of Ingredients
Other ingredients in your formula can affect how fragrance comes through.
In candles: The wax type, dye, wick, and even the vessel can impact scent throw.
In soaps: Butters, clays, milks, and even natural additives like honey can soften or modify a fragrance. Goat’s milk soap, for example, tends to warm up and round out scents, while coconut-heavy formulas can sometimes intensify citrus.
How to Work With These Differences
If you’re testing a fragrance for multiple applications, consider:
- Testing in small batches before committing to a large pour.
- Adjusting your expectations - some fragrances are rockstars in wax but struggle in soap (or vice versa).
- Blending strategically - sometimes, tweaking a scent with complementary notes can help it shine in different mediums.
So next time you notice a fragrance oil smelling different in a candle vs. soap, remember, it’s not the oil, it’s the environment. And if you ever need help finding an oil that performs well across both, well… you know who to ask.