During my most recent visit to Minjerribah, North Stradbroke Island, I was amazed to see a lot more pumice stone on the beach than there usually is. I’ve always loved the iconic Australian brand ‘Solvol’ soap, which is no longer available but was made with finely ground pumice, so it was a perfect opportunity to make some for myself!

Note: It is strictly prohibited to remove any material from National Parks, and beaches in some states of Australia. Please check your local laws and consider any potential collecting with care (see below for more information).

Make sure you watch the video for a full demonstration of the recipe, including some nice beach scenes we filmed on the trip.

If you are new to soap making, please ensure you visit this page and view my soap making safety essentials video for all the information you need to start making soap yourself at home.

I also highly recommend learning to calculate your own soap recipes (and check others’ recipes before you use them - read my disclaimer).

These videos will get you started with the basics of soap recipe formulation and calculation:

• How to Calculate Your Own Soap Recipes

• Calculating Water in Soap Recipes and Clarifying 'Lye Concentration'

• Choosing Oils for Soap Making - Oil types and fatty acids, balancing recipes and Soapcalc explained 

• Superfat Explained - Understanding 'Superfat' and 'Lye Discounting' in Handmade Soap Making

  
  

Pumice Stone Cold Process Soap

RECIPE SPECIFICATIONS

• 1250g (1.25kg) total soap batter volume (excluding pumice)
  I calculate my soap recipe volumes to fit my chosen moulds using this method
  I used two of these olive design silicone moulds (affiliate link) and one of these mini loaf moulds for this recipe.

• 871g total oils (not including essential oils)

• 6% superfat

• 2:1 water to lye ratio

• Essential oils 3% of base soap recipe oil amount

INGREDIENTS

• 246g water
  I used fresh sea water that I store in my fridge. You can use filtered tap water or distilled water.
  Feel free to dissolve 7g of salt into your water to replicate sea water (sea water is approximately 3% salt water solution).

• 8.7g citric acid
  Use food grade citric acid from the supermarket or a soap ingredients supplier.

• 128g sodium hydroxide (adjusted for citric acid)
  IMPORTANT: This recipe is calculated to be made with citric acid, which improves the shelf life and performance of handmade soap, especially in hard water areas. If you do not have citric acid please use only 123g of sodium hydroxide. Every gram of citric acid consumes 0.624g of sodium hydroxide in the lye solution, therefore extra sodium hydroxide is required if citric acid is used.

• 696g tallow, palm oil or lard
  I used a combination of beef tallow and RSPO certified palm oil. Tallow, lard and palm oil all have a very similar fatty acid profile and can be used interchangeably in this recipe. I used this method to render tallow from grass-fed beef fat I purchased from a local butcher.
  (My coffee soap or laundry soap recipes would be great alternatives if you want to avoid animal fats and/or palm oil).

• 174g coconut oil

• Ground pumice stone (see note below)
  I used about 2/3 cup finely ground stone for this batch, but I could have used more. Add as much or as little as you like depending on how abrasive you want your soap to be.

• 27g essential oil
  I used a combination of cedar, tenfold orange and lemon myrtle.

Regarding collection of pumice stone from the natural environment

My understanding of the law in Queensland is that it is permitted to collect small amounts of material from public beaches (I do not remove shells though), however it is strictly prohibited to remove any material whatsoever from a National Park anywhere in Australia. It was brought to my attention while editing this video that in some jurisdictions in Australia it is strictly prohibited to remove any items from the natural environment in any location (National Park or otherwise). In retrospect, I may not have collected the pumice stone from the beach this day, however I have been visiting this island since early childhood, it is a very special place for me (that feels like home), and I have to admit I did not think about it at the time. I will be more careful about this in future. I decided it was still worth sharing the video to demonstrate how pumice stone can be used in a soap recipe.

Please source your ingredients for soap making wisely. You can purchase pumice stone online in Australia from many of these suppliers.

METHOD

Please read: the what and how of soap making if you are new to this craft
You may also want to consult my soap making terms page

1. Make sure you are fully aware of the safety requirements of soap making. This video contains the essential information needed.

2. Watch the video demonstration of me making this recipe on Youtube.

3. Prepare pumice stone. Grind finely in a granite mortar and pestle if needed.

4. Prepare essential oils, if using. This soap can be made fragrance free if desired.

5. Prepare soap moulds. Use firm cardboard, corflute or cutting boards under silicone moulds if using (makes them a lot easier to move).

6. Weigh out the oils/fats for the soap recipe. I placed my tallow, palm oil and coconut oil in the sun for a while to soften before weighing.

7. Gently melt fats over a double boiler or for short bursts in a microwave on low power, until the mixture is translucent and fully melted. You may need to cool it after melting before you make the soap. The ideal temperature to aim for is around 50°C / 122°F.

8. Weigh citric acid, if using, and set aside.

9. With safety gear on (full goggles and gloves at minimum), weigh sodium hydroxide into a small container with a lid and secure the lid without delay to prevent clumping.

10. Weigh water into a no. 5 heat safe plastic or stainless steel jug and dissolve citric acid into the water.

11. When you are ready, with goggles and gloves still on, carefully add the sodium hydroxide to the water/citric acid solution. Stir slowly as you do this to encourage it to dissolve. Once dissolved, set this solution aside somewhere safe. Rinse off the spoon used to stir this mixture IMMEDIATELY. Allow the lye solution to cool to around 50°C / 122°F.

12. When all of your ingredients and equipment are in place and the oils and lye solution are at the recommended temperature, carefully pour the lye water solution into the oils and begin to stir by hand.

13. Using an immersion blender, blend the soap mixture in brief bursts, stirring in between, until the batter lightens in colour and starts to emulsify. Once the mixture appears homogenous and uniform, continue mixing with a whisk.

14. If you are adding essential oils, pour them into the soap batter and stir in immediately with a whisk.

15. Add ground pumice to the soap batter and continue to whisk until evenly distributed.

16. Continue stirring until the soap batter starts to thicken slightly (a light to medium trace is sufficient) then pour the soap carefully into the mould/s.

17. Cover the soap moulds, wrap with a light blanket and place somewhere enclosed or insulated to encourage the soap to gel. If using individual silicone moulds, leave the soap until the next day before unmoulding. If using a log mould, the soap may need to be checked sooner and cut before it becomes too hard. Check after a few hours and cut when it is firm enough to do so. Use gloves to handle fresh soap if it has not yet fully saponified.

18. Cure the soap for 4-6 weeks using. Don’t forget to test your soap before using it, here’s how to do that.

Please view the video for a full demonstration of this recipe.

If you are new to soap making, please START HERE

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Please leave any comments and questions in the section below.

Enjoy your soap making!
Elly 🌸

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