Which essential oils last well in soap?

Why does my lemon soap not smell of anything?

How do I know which essential oils work well in soap?

It is no surprise to know that identifying which essential oil blends stick well in soap, particularly cold process soap, is a topic that I get asked about every week without fail. I think virtually every soap maker out there has experienced the disappointment of a batch that smells of nothing after a 4 to 6 week cure time.

So I felt it was a good idea to have a discussion around this and talk through what does work, what doesn't and why. 

Before looking through the oils themselves, there are a few simple things that help make sense of why some scents last and others disappear.

Understanding scent notes in soap

Top notes on their own are short lived and will fade quickly in soap. They are best blended with mid and base notes rather than used on their own.

Mid notes often work well by themselves and even better when they are blended with a base note.

Base notes last the longest. Some of them can dominate a blend so it is worth being aware of that when you are creating combinations. Ylang ylang is a good example of this.

The reason these notes behave differently comes down to molecule size. Top notes are made up of smaller molecules. They evaporate quickly which is why they fade faster in soap. Mid notes have slightly larger molecules so they last a little longer. Base notes have the largest molecules which is why they tend to stay in the soap for much longer.

Once you understand this it becomes much easier to see why certain blends work well and why others disappear.

A note on citrus oils

Citrus oils are often the ones people struggle with most. Lemon is the classic example. Many people make a lemon soap and then after curing there is very little scent left.

One approach that works well is blending a number of citrus style oils together rather than relying on a single one. For example I have had good results using a combination of lemongrass, may chang, lime and bergamot. Together they create a lovely lemon style scent and the fragrance lasts far longer. You can still smell it weeks and months later.

Another way to think about citrus oils is to accept that they do not always need to be the main scent. Grapefruit is a good example of this. In a blend you might not clearly smell grapefruit in the finished soap, but it can lift and lighten the overall fragrance. So rather than expecting it to dominate the scent it can be useful to think about the role it plays within the blend.

A quick introduction to what sits where

TOP NOTES

• Bergamot - sweet/fruity - try with citrus, vetiver or lavender
• Lemon - fresh/crisp - try with lavender, cedarwood
• Orange (sweet) - sweet/fruity - try with geranium, cinnamon leaf, vetiver
• Grapefruit - fresh/citrus - try with eucalyptus, patchouli, black pepper, ylang ylang
• Lime - fresh/citrus - try with citrus, lemongrass, cedarwood

TOP/MID NOTES

• Peppermint - strong/minty - try with lavender, rosemary, eucalyptus, tea tree
• Spearmint - fresh/minty - try with lime, vetiver, clary sage
• Clove - warm/spicy - try with geranium, citrus, lavender, ylang ylang

MID NOTES

• Clary Sage - herbaceous - try with lime, patchouli
• Geranium - sweet/floral - try with sweet orange, clary sage, peppermint
• Juniper Berry - floral - try with rosemary, eucalyptus
• Eucalyptus - strong/fresh - try with tea tree, spearmint, rosemary
• Tea Tree - medicinal/fresh - try with peppermint, lavender, lime
• Rosemary - medicinal/herbaceous - try with lavender, patchouli, lemongrass, peppermint
• Lavender - herbaceous/floral - goes with pretty much everything !!
• Lemongrass citrus/strong - try with lavender, citrus, geranium

BASE NOTES

• Cedarwood - mild/woody - try with lavender, lime, eucalyptus, sandalwood
• Black Pepper - spicy/sharp - try with vetiver, geranium, citrus and lavender
• Cinnamon Leaf - spicy/strong - try with sweet orange, clove (use very sparingly)
• Patchouli - earthy/musky - try with ylang, cinnamon, rosemary, lemongrass
• Vetiver - warm/spicy - try with bergamot, patchouli, sandalwood, citrus
• Ylang Ylang - strong/floral - try with citrus, patchouli, geranium, sandalwood
• Sandalwood - woody/warm - try with citrus, bergamot, lavender, geranium

This is just a guide to whet your appetite and get those creative juices going. Do remember that you can use a mid or base note on it's own so if you love geranium soap, great, make geranium soap and do not feel obliged to add anything extra in to the mix.

Need some more inspiration, grab my 101 Essential Oil Blends For Soap That Last eBook.

I hope you found this useful. Good luck with the blending.