Testing Fragrances Part 3

Now that we’ve talked about discolouration in quite some depth in the past two posts, it’s time we have a look at some of the other problems that fragrances can cause in soap making.



Acceleration is the most common problem that can happen with fragrances, but also with certain essential oils. This is when the soap mixture thickens more quickly than usual. Acceleration is difficult to predict, and there a number of components or combination of components in a fragrance that can cause acceleration. In some cases, a fragrance can cause such a quick acceleration that the soap already solidifies in the soap pot. When that happens, we call it ‘seizing’, and fragrances that cause seizing are unsuitable to work with in hot or cold process soap making. Accelerating fragrances are difficult but not impossible to work with.

Soap that has seized in the pot after adding fragrance.

Some tips to working with accelerating fragrances are

  • use a larger percentage of slow moving (soft) oils, such as olive oil, rice bran oil, sunflower oil, keep your hard oils (solid at room temperature) and butters at a minimum
  • don’t use a water discount – have at least a 2:1 water to caustic soda ratio
  • making sure you work with cool soaping temperatures (both the oils and lye at room temperature)
  • don’t use a stick blender, but whisk your soap mixture by hand (using a whisk) until emulsified and don’t over-whisk, leaving your mixture at a thin trace
  • check your additives – certain additives, such as honey, milk, flours and clays can also speed up acceleration
  • if you are using a blend of fragrances and/or essential oils, mix them together before adding them to the soap

And lastly, change your design so it doesn’t involve delicate colour work such as swirls, and stick to simple layers or solid colours, allowing you to scoop the soap into the soap mold.

Some fragrances can cause soap to accelerate (thicken)


Ricing and separation

Ricing occurs when the fragrance binds to the hard oils and doesn’t affect the other oils in your soap. When this happens, your soap mixture will resemble something like a rice pudding, with little solid rice shaped blobs of soap in a more fluid soap mixture, hence the term ‘ricing’. If the ricing is not too extreme, try whisking or stick blending the soap mixture to smooth it out. If the ricing is quite advanced, you can try and save the soap by cooking it in a double boiler (also known as bain marie method), and then stick blending it. Note that stick blending will cause the soap mixture to thicken.

Separation is the opposite of ricing, and happens when the fragrance can’t be incorporated into the soap or only partially. You can tell when this has happened if there is oil pooling on top of the soap that just won’t mix into the soap, no matter how much you whisk or stick blend it. Both ricing and separation can occur together, and are sometimes difficult to tell apart. Again, you can try cooking and stick blending the soap to rescue a soap that has separated due to a fragrance.

This soap has experienced ricing and subsequent seizing.


Some fragrances cause a rise in temperature, which can also lead to acceleration or ricing. When you use such fragrances, it is important to make sure you soap at very low temperatures to avoid a hot gel. In extreme cases, if the soap gets too hot during gelling, your soap can expand and rise out of the soap mold, literally erupt. This effect is called the volcano effect, and I’ve had it happen to me twice. The soap is perfectly fine to use, and just scoop the soap back into the mold using a spatula and wearing your gloves, as the soap will be very hot.

Because it is difficult to predict how soap will behave with certain fragrances, soap makers are dependent on testimonials from other soap makers or from their own experiences. Some fragrance suppliers will test their fragrances in cold process soaps and supply the results on their websites.

To help you out with the Candlescience fragrances available from Pure Nature, I’ve made a list with the ones I have tested so far, and I’ll be adding to this list as I test more.

Candlescience Skin-Safe Fragrances

Abbreviations   A: acceleration R: ricing D: discolouration

  • Chocolate Fudge – vanillin content 1-5%, no A, no R, brown
  • Christmas Tree – vanillin content 1-5%, light A, no R, pink beige
  • Clean Cotton – vanillin content 0%, no A, no R, no D, WHITE FRAGRANCE
  • Coconut Lime – vanillin content 0%, no A, no R, light beige
  • Creme Brulee – vanillin content 3-5%, no A, no R, dark brown
  • Cucumber Mint – vanillin content 0%, no A, no R, no D, WHITE FRAGRANCE
  • Day at the Spa – vanillin content 0%, fast A, hot gel, no R, brown,
  • Driftwood – vanillin content 3.05%, no A, no R, dark brown
  • Egyptian Amber – vanillin content 1.71%, no A, no R, amber
  • English Garden – vanillin content 0%, slight A, no R, off-white
  • Fig Tree – vanillin content 0%, fast A, no R, light pink beige
  • Fresh Coffee – vanillin content 1-5%, slight A, no R, caramel
  • Garden Mint – vanillin content 0%, no A, no R
  • Gingerbread – vanillin content 0%, slight acceleration, no R,
  • Holly Berry – vanillin content 0%, can cause ricing and seizing, light yellow.
  • Love Spell – vanillin content 0%, no A, no R, no D, good for colour work, slows down trace, off-white
  • Mediterranean Fig – vanillin content 0%, no A, no R, great for colour work, off-white
  • Mistletoe – vanillin content 0%, no A, no R, no D, great for colour work
  • Oakmoss and Amber – vanillin content 0%, slight A, hot gel, no R, mauve-tan
  • Plumeria – vanillin content 0%, no A, no R, off-white
  • Pumpkin Pie – vanillin content 0.6%, no A, no R, brown
  • Rose – vanillin content 0%, fast A, no R, creamy ivory
  • Sage and Pomegranate – vanillin content 0%, no A, no R, cream
  • Strawberry Shortcake – vanillin content 5-10%, no A, no R, brown

I’d love to hear your experiences with Candlescience fragrances, especially the ones I haven’t tested yet!

Author: Jackie

Mum, blogger, soap maker, frequent flyer!

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