So after my introduction to soap-making, here’s the actual do-it-yourself part. Make sure you read Soap-making part 1 for the chemistry behind it all, and Soap-making – the equipment for the  list of material you’ll need every time you make soap.

I took this recipe from Aroma-Zone’s website, which is in French but here’s a direct link. You need just three ingredients: olive oil, babassu oil and caustic soda (sodium hydroxide or lye).

The three ingredients for my soap

The three ingredients for my soap

The original recipe used a commercial caustic soda solution at 30.5%, but the one I bought (at Leroy Merlin, a French DIY chainstore) is at 30% (by the way, I couldn’t find pure caustic soda in crystal form to dilute, but buying a ready -made solution takes out one of the trickier stages of soap-making, which is making your lye solution!).

That 0.5% makes a difference, believe me! This is where you MUST read the label on your bottle and recalculate the amount of sodium hydroxide needed using a lye calculator . This one‘s in French from Aroma-Zone (it’s what I used). This site gives you a selection in English  (Soap making essentials). 

Olive oil soap

255 g (85%) olive oil

45 g (15%) babassu oil

128 g Caustic soda solution at 30% solution

(In fact the lye calculator I used gave the following:

127.3 g Caustic soda solution (reduction of 10%) OR

128.7 g Caustic soda solution (reduction of 9%)

As my scales aren’t precise enough to do .3 or .7 of a gram, I chose the nearest round number to these two measurements i.e. 128 g, as it will stil give me a good superfat content .)

Working at room temperature is the easiest way to make your soap , but it means you’ll have to “cure” your soap for at least 4 weeks.


1 Weigh out precisely the olive oil and babassu oil in a pyrex/glass/plastic bowl (see under material in previous post).


2. Calculate the quantity of caustic soda you will need depending on the dilution of your sodium hydroxide.

3. Weigh out precisely the caustic soda solution as per the lye calculator above.

Weighing out caustic soda in a pyrex jug

Weighing out caustic soda in a pyrex jug

4. If using oils which are solid at room temperature (which is the case for Babassu oil), melt oils together in a bain marie (double boiler, or just put your bowl over a pan of simmering water). Once melted, take them off the heat and let them cool down but not solidify!

5. Pour the caustic soda solution slowly into the oil mixture (AND NOT THE OTHER WAY AROUND)

p1060983and start mixing it with a stick blender. You should stop and restart regularly so as not to overheat your blender, but keep mixing it by hand when it’s not turned on.


6. When the mixture starts to thicken and leave a trace (see photo), it’s ready.

The trace

The trace

This is the time to add any ingredients like essential oils, extra oil, colours etc. but I’ve kept to a plain soap for my first foray into soap-making to make sure I get the basics right first. I’ll let you know when I become more adventurous!

7. Pour the mixture into your moulds. You might want to “tap” the mould lightly to get an even spread and to get rid of any air pockets.

p1060987You should use a silicone spatula to get every last bit of mixture out.

8. Cover the moulds with clingfilm and then wrap in a tea towel or a small blanket (like a cot blanket)  to keep in the heat and accelerate the saponification process.

Freshly poured soap - now the waiting starts...

Freshly poured soap – now the waiting starts…

9. Leave the soaps to harden for 24-48 hours out of reach of children and pets (the caustic soda remains caustic until the soaps are fully “cured”).

10. Unmould.



Now leave in a dry and well-ventilated place for at least four weeks to “cure”(still out of reach of children and pets). I’ve left mine in the garden shed. And am waiting (im)patiently for them to cure!

Curing allows the chemical reaction which takes place between the oils and the caustic soda to finish, giving a gentle soap. It also allows the soap to dry and harden which will make it longer-lasting (a soap that is too soft i.e. too “fresh” will melt easily).

Note that the properties of different soaps (lather, creamy texture, durability) improve with age.

I made mine on September 23 so need to wait until at least October 21 to see if they’re ready…I’ll keep you posted.