Lemon Myrtle Soap

Due to my keen interest in gardening and also science, I like to distil essential oils from plants (I will describe my distillation hobby in another post). I take the trimmings from plants that i grow and rather than throw them in the compost, i run them through my steam distillation apparatus and extract the volatile oils from the plant matter.

After extracting a few different types of essential oils and not having much of a use for them other than oil burners and eucalyptus oil for it’s cleaning/solvent properties, I decided to try and find another use for them. The outcome of my brainstorming was to make soap!

Home-made soap would make a great christmas gift, saves money if i use it at home and is fun to make!

I chose to use Olive oil and refined coconut oil as the base, lemon myrtle fine ground leaves and essential oil for scent and exfoliation and green Argiletz clay for colour. This method is called “Cold Process” soap making

Lemon Myrtle Soap

Lemon Myrtle Soap

The recipe was somewhat like this:


  • 800g Extra Virgin Olive Oil
  • 200g Refined Coconut Oil
  • 350g water
  • 130g Sodium Hydroxide (caustic soda/lye)
  • 1/4 cup Lemon Myrtle leaves finely ground
  • 15g Lemon Myrtle essential oil


  1. Add caustic soda to 350g water (don’t add water to caustic soda unless you want dangerous mess all over the place) the mixture will heat up rapidly and give off nasty fumes so do it outside. Let the mixture cool a bit as you do the next step
  2. combine olive oil and coconut oil in stainless pot on the stove, heat until it is about 55 degrees C
  3. using a stainless thermometer, measure the temperature of the oil and the caustic soda solution, when they are between 40 – 50 degrees C, combine them by carefully pouring the caustic into the oil. If the oil cools too much, you can reheat it lightly but don’t reheat the caustic. If the caustic gets too cold, you are better off remixing a new batch.
  4. using a combination of a stainless shaft stick mixer and stainless stirrer, mix the oil and caustic together until light trace (trace is when you can pour a little of the mixture over the surface and it will sit there for a few seconds before dissolving back into the mix.
  5. now is the point where you mix in the essential oil and leaves, combine well by hand stirring with the stainless stirrer (you  don’t want to mix it too much, that’s why you don’t use the stick blender)
  6. carefully pour the soap mix into an empty 1L milk carton and close the top. wrap lots of towels around the milk carton as insulation so that it doesn’t cool down too quickly and set aside until the next day
  7. after about 18-36 hours, tear off the milk carton and slice the soap into blocks, my recipe made about 11-12 good size blocks of soap.
  8. place the soap blocks onto a rack to dry for 3-6 weeks, turn them over about once a week.


  • Be really careful when dealing with caustic soda, it is very dangerous and can cause severe burns. Wash it off thoroughly and immediately if you spill or splash it anywhere. White vinegar can be used to neutralise the caustic effect.
  • don’t use pots/pans/mixers/etc that you intend to use again for cooking. go and buy a cheap set of equipment that you can keep specifically for soap making
  • always use a soap calculator to work out how much caustic soda to use for your recipe. Here is a simple one: http://www.australiansoapmaker.info/ozcalc/lye.php
  • be PRECISE when measuring out oils/caustic soda/water, the results will be severely affected if you are not exact in your measurements.


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    • Katie on March 10, 2014 at 6:51 am
    • Reply

    You mention in the ingredients 350g of water but if you read the recipe instructions you wrote 300g of water??
    Is it 350 or 300?

    1. oops! sorry about that, i’ll fix the recipe right away. It is 350g water

    • Deb on December 29, 2014 at 9:18 am
    • Reply

    When did you add the clay and how much did you use?

    1. Hi Deb, I added the clay to the water used to mix with the caustic soda. from memory it was around 2 tablespoons but it was a while ago so that memory is a bit faded. I usually experiment and just keep adding more until i like the colour.

        • Deb on December 29, 2014 at 9:24 am
        • Reply

        Thanks James. I’m also hunting your blog for how you made your lemon myrtle essential oil. I’ve been searching the web and I can’t find a lot. I’ve got a massive tree in my yard and would love to be able to put that smell to good use!

        1. No worries! happy to help, glad someone has got something useful from this blog. Since that first batch of lemon myrtle soap i have made around 150+ other types of soap so plenty of experience now. If you need any info or want to show off your work just let me know! As for making the essential oil (it is an extraordinary scent, i love it) i use some steam distillation glassware from http://www.heartmagic.com/EssentialDistiller.html

          I have the 5L biomass flask upgrade too, it makes it a lot easier to get a good amount of oil. I don’t think i’ve posted anything on this blog about it but maybe i should!

    • Deb on December 29, 2014 at 9:59 am
    • Reply

    Thanks! I’ll look into it 🙂 keep you up to date with my results.

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