Have you ever noticed that certain essential oils cause your soap to harden more quickly than usual? I remember once adding an essential oil that accelerated tracing and resulted in crumbly soap. On another occasion, I used patchouli essential oil for my soap, and it turned brownish-yellow rather than the pale yellow of the base oil that I wanted to retain.
Other times, I noticed that the essential oil I used did not retain its scent over time as it dissipated. Initially, scents like rosemary and clary sage were strong, but they became more subtle over time.
Since then, I've been more mindful when using essential oils in my soap crafting. Depending on whether it's for the body or face, I carefully choose the type and amount of essential oils to achieve the desired design and functionality.
In soap making, "trace" refers to the point in the mixing process where the oils, lye, and water have emulsified to the extent that they cannot be separated again. When the mixture reaches a light trace, it indicates that it will continue to thicken and harden on its own.
The three different stages of trace are listed below:
Light Trace: The soap mixture is just beginning to emulsify and is still fluid enough to manipulate easily.
Medium Trace: The soap mixture has thickened further, resembling a thin custard consistency.
Thick Trace: At thick trace, the soap mixture has significantly thickened to the point where it leaves a trace or "ribbon" when drizzled back onto itself.
The use of essential oils will influence trace in soap making. Certain essential oils accelerate the tracing process, which impacts the final outcome of your soap. For instance, adding fast-tracing essential oils during medium trace can rapidly transition the mixture into thick trace within seconds, potentially changing the soap's design if a smoother texture was originally intended.
Here is a reference list of essential oils categorized by their tracing behavior through our experimentation in the studio:
Fast Tracing:
Cinnamon Bark, Lavender, Citronella, Nutmeg, Clove Bud, Rose Geranium, Geranium, and Ylang Ylang
Non-Fast Tracing:
Cedarwood, Lemon Eucalyptus, Clary Sage, Lime, Eucalyptus, Peppermint, Fir Needle, Rosemary, Ginger, Sweet Orange, Juniper Berry, Tea Tree.
Apart from affecting the trace stage, essential oils can also change the color of soap. For example, vetiver and patchouli essential oils are brownish-yellow and will change the color of your soap if no other additives are used. To counter this effect, you can add mica, oxide, or titanium dioxide to retain the original color.
As a general guideline, we recommend the following quantities (in ml) when adding essential oils to your total soap weight:
2-3% for heavier base essential oils (thick in texture and typically woody/herbal in scent).
4-5% for essential oil blends (mixing of 2-3 different essential oils).
6% for pure citrus essential oils.
These recommendations help ensure a balanced and effective use of essential oils in soap making, considering their textures and scent profiles.
Lastly, the scent of essential oils in your soap will diminish over time due to several factors:
Oxidation and evaporation
Exposure to light and heat
Improper storage of the cured soap
Top note essential oils fade more quickly, while others gradually develop a subtler scent. To preserve the scent, wrap your soap in cling film and store it in an airtight container. Separating different scents into different boxes will ensure they don’t mix.
Check out our blog post on essential oil blending https://www.sugarandspice.com.sg/post/essential-oil-blending where we provide recommendations for blends.
*Other factors that can affect trace include the type of oils or butter, temperature, additives used in soap making.
Happy soapmaking! 💛
Love,
Sugar & Spice
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