Selecting a combination of essential oils or fragrance oil to scent a soap recipe is a favorite part of the process for many of us. Some aromas can even inspire the colors, additives, and designs we use in a batch of soap. Nothing is more disappointing than picking up a cured bar from your latest batch of soap and realizing that parts or all of that amazing scent have faded away. Cold process soap making is a harsh environment and some essential oils and fragrance oils are sensitive to the changes in temperature and pH level that happen along the way.
Below we’ll go over some tips on making aroma last longer in our soap.
Use the Right Amount
Usage rates play an important role in the retention of scent. For a powerful scent, you can add around .8 ounces of fragrance or essential oil per pound of cold process soap. This number will vary some based on the specific essential or fragrance oils being used. We should always be sure to research the usage rates of any oils we want to add to soap and let that help inform our decisions on how to best use it.
Anchor the Scent
One thing we can do to help our scent stay in our soap is to choose oils that are less prone to fading in the first place. Citrus oils, like lemon, sweet orange, and grapefruit, light florals like lavender and chamomile are essential oils that we would love to use in soap but their scent tends to fade during the soap making process or shortly after. When we want to use an essential oil or two that may fade in soap, it is best to combine them with oils that have more staying power to help anchor the scent. Generally, base notes are scents that will hold best in cold process soap but they are not the only option for anchoring a blend.
There are a variety of essential oils that do well in soap and help to anchor fragrance blends. Below is a list of some of our favorites.
Aroma anchors for deep, spicy blends:
- Patchouli Essential Oil
- Vetiver Essential Oil
- Sandalwood Essential Oil
- Cinnamon Essential Oil
- Clove Essential Oil
Aroma anchors for fruity, floral blends:
- Litsea cubeba Essential Oil
- Lemongrass Essential Oil
- Geranium Essential Oil
- Ylang Ylang Essential Oil
Aroma anchors for fresh, herbal blends:
Pick the Right Oil
Citrus essential oils are one of the top culprits for scent fading so more concentrated or folded versions of those essential oils, like Orange 5X, can help lessen scent fading as well. Fragrance oils are another great option for anchoring essential oil blends or being used on their own to scent a cold process soap recipe. They generally have an intense aroma and their formulas are not as sensitive to the soap making process.
Popular fragrance oils for soap making:
- Rose Fragrance Oil
- Vanilla Fragrance Oil
- Apple Cider Perfume
- Raspberry Perfume
- Chocolate Perfume
- Xmas Memory Fragrance Oil
- Leather Perfume
- Nag Champa Perfume
Using Clay and Other Dry Additives
This may surprise some, but certain types of dry additives can also help scents stay in soap longer, especially clay. Clay is very fine and absorbent, allowing it to soak up some of the essential oils in the soap while the other excess liquid evaporates away. Clay has the added benefit of adding a nice slip to the soap and some varieties can also lend a subtle color to the finished bar. Cornstarch and other starches are also popular options with similar benefits.
Curing is the last step to the soap-making process and another place where we can help to ensure that our beautiful scents stay in the bar. Soap should be placed in a cool, dry place out of direct sunlight to cure. Avoiding any additional heat or sunlight will help reduce scent fading in this crucial final step.