Castile soap is a hard, pure and verymild soap with great moisturising properties (and in the shops it's bl**dy expensive)
Ingredients
1litre Olive oil (try to get the cheapest lowest quality oil as it's actually better for soap making)
130g Caustic Soda (Soude Caustique in French, Mr. Bicolage sells it as paint stripper)
400ml Water (rain water if you can get any
)First of all suit up like a spaceman - rubber gloves, goggles etc cos Caustic Soda's v nasty stuff.
put COLD water in a saucepan (NOT ALUMINIUM ONE!!!)
Slowly add the Caustic Soda and stir until dissolved (try not to breathe in the fumes - there isn't really much fumes but don't stick your head in the pan and sniff)
The solution will get hot but this is normal.
Allow to cool for about an hour.
When it's all dissolved add the oil slowly and stir constantly and slowly so as not to splash
and keep stirring
and keep stirring
and did I mention to keep stirring (you can use a blender on a slow setting)
after about 30 minutes of stirring it will thicken to a pea soup consistency - this is known as "trace" cos the spoon leaves a trace on the surface.
Now you can add any frangrances you want - orange blossom's quite good
Now pour into a mould - something like a flat baking tray and leave until solid - this can take a few days so be patient
Remove from the mould (I line mine with grease proof paper to make it easy) and cut into bars with a warm knife
The bars now need to be left for at least 4 weeks to cure, turning every day. This makes sure all the caustic soda is gone (although in theory it should be gone within 1 day but better to be safe)
Now you have bars of soap.
You can try any oil or lard or a mix but keep the quantities the same (always 1 litre oil to 130g soda)
Palm oil and coconut oil add a better lather.
Oh and one last thing - don't clean your tools (spoons etc) for a couple of days just to make sure you are not rinsing caustic soda down the plug hole - not good for the environment
As long as you treat the soda with respect you'll have fun.
One last thing, never add soda to hot water - it spits!!
(doctor of chemistry)