How to prevent scent from fading in homemade soaps

Has this ever happened to you? A month ago, you made a divine, summer-scented soap. But now that your soap has cured, your wonderful coconut-orange-pineapple creation smells like… nothing at all! It’s not always easy to keep your homemade soaps smelling strong. A number of influencing factors may cause scent to fade, if not disappear, over time. Luckily, there are solutions! That’s why we decided to put our many years of soapmaking to good use and share all our secrets for making scented soap and preventing that scent from fading!

Trick #1: Use the right scents in your homemade soap.

There are three kinds of notes in perfumery:

• Top notes, which evaporate quickly
• Middle notes, which come on after the top notes
• Base notes, which last the longest

Generally speaking, the scents that hold best in soap are base notes. These essences are not very volatile and will last the longest. They will also help anchor the middle and top notes, which fade more easily. We recommend that you always put base notes in your recipe. With their help, your cold process soap will keep its scent longer!

Some examples of base notes:

• Woody notes: Atlas cedar essential oil, patchouli essential oil, Ho wood essential oil, rosewood essential oil
• Spicy notes: vetiver essential oil (very effective fixative), clove essential oil (dermocaustic and accelerates trace), ginger essential oil (dermocaustic), cinnamon essential oil (dermocaustic)
• Sweet notes: bezoin essential oil (accelerates trace but a very effective fixative), almond aromatic essence, honey aromatic essence (accelerates trace)  
• Amber notes: sandalwood aromatic essence 

Of course, you don’t have to use only base notes in your scent blend—quite the opposite! You can complement them with other aromas. Some essential oils and aromatic essences keep their scent well, even if they are not base notes. 

Other scents that last well in soap:

• Fruity notes: fig aromatic essence
• Citrus-like notes: petitgrain essential oil, litsea essential oil, lemongrass essential oil 
• Floral notes: jasmine aromatic essence, true lavender essential oil, palmarosa essential oil, rose geranium essential oil, ylang-ylang essential oil, Bulgarian rose essential oil, violet aromatic essence     
• Herbaceous notes: rosemary ct cineol essential oil, coriander essential oil, eucalyptus essential oils (lemon-scented, globulus, or radiata)    
• Fresh notes: peppermint essential oil (dermocaustic), spearmint essential oil (dermocaustic)
• Woody notes: scotch pine essential oil, black spruce essential oil 

Keep the above in mind when developing your recipe and you’ll be able to put together a lovely scent blend that will last well. 

Warning: If one of your chosen essential oils or aromatic essences accelerates trace, then you must increase the ratio of water to sodium hydroxide  (the ratio of water to sodium hydroxide can be between 1.75 and 2.25). Your soap will then take longer to dry. If you’re a beginner soap maker, we recommend not using ingredients that accelerate trace at first. 

Trick #2: Work at low temperatures.

The aromatic molecules that give essential oils their scent are volatile compounds, which means that they quickly evaporate as temperature increases. As saponification is an exothermic reaction, heat is released during cold process soapmaking. To prevent the soap from getting too hot and the scent from evaporating, it is important to work at low temperatures (around 30°C if possible). This is one of the reasons why essential oils and aromatic essences must be added at the end of the process.   

Trick #3: Hooray for clay!

Clays are known for their ability to capture and absorb molecules, including odours and scents. Clay will trap scents in your homemade soap so it keeps its lovely smell longer.

To use, just mix 1–3% clay (on the total weight of oils) to your essentials oils and add when you reach trace. All clays will work: white (kaolin), pink, red, green, yellow, and even ghassoul! They will also make your soap creamier and increase lather. A perfect solution, don’t you think?!

Keep in mind that adding clay can affect the final colour of your creation. If you want this effect to be as subtle as possible, we recommend using white clay. It will make the colour of your homemade soap slightly paler, without impacting the final colour too significantly. Coloured clays will add a lovely, earthy, and very natural colour.

Trick #4: Orris root powder, your new ally in making scented soaps!

Orris root powder has been used for several centuries in perfumery. This renowned ingredient is an excellent scent fixative in soaps and other creations, including deodorant and solid perfumes!

We suggest using three grams of orris root powder per kilogram of oil in your recipe. Mix it into your essential oils, then add the mixture to the soap batter when you reach trace. Orris root powder can add a gentle exfoliating effect to your soap. 

Now you’re all set to make the scented soap of your dreams! Don’t hesitate to share your favourite recipes and scent blends with us—you might inspire others!  

Trick #5: Use starch.

Starches can be used help cold process soap keep its scent. Cornstarch, tapioca starch, and arrowroot powder all work well. Use them exactly like clay: add 1–3% starch (on the total weight of oils) to your essentials oils and butters and add the mixture when you reach trace. Starch will also make your soap slightly softer, though to a lesser extent than clay. 

Better together?

Now you know how to make your cold-pressed soaps retain their scent! Each of these tricks works well alone… but you might be wondering, can you combine them together? Well, it depends! 

Tricks 1 and 2 can be used together without a problem. If you want, you can also add trick 3, trick 4, or trick 5 in with tricks 1, 2, or 1 and 2 together, of course making sure to respect the proportions listed in this article. However, please note that if you want to combine one or more among tricks 3, 4, and 5, you’ll need to recalculate the proportions of each scent-fixing ingredient. 

Just remember that using all the tricks together won’t add up to a super long-lasting scent in your soap! Using just one trick can be enough, just as using a mix of several (1, 2, and 5, for example) can also be worthwhile. The best plan is to try things out for yourself to see what solution you like best.