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Making All Natural Castile Soap

A Handmade Pure Olive Oil Soap
Making All Natural Castile Soap

Making All Natural Castile Soap is pretty simple when you know how?  Castile Soap is made out of Pure Extra Virgin Olive Oil, Sodium Hydroxide (Caustic Soda) and Water.  That’s it.  Just three things will make the most amazing, traditional & timeless soap in the world.  It is best cured for as long as possible to allow it’s true beauty to unveil itself and by a long cure, I mean 9 months or more.  Soap used early does unfortunately get used up fast as it’s a little soft and it can also tend to be a little slimy.  So my advice is to try it at intervals, along the way and after it has reached at least 8 weeks of age. You’re best reviews will be obtained when your soap is over 6 months of age, when it is at it’s best.

Castile soap has it’s origins hotly debated amongst soap makers and people that are interested and I dare say that the exact origins will be hotly debated forever.  The debate would certainly have to include Aleppo Soap, founded nowhere else other than Aleppo?  All claims must surrender where Aleppo Soap is concerned as it was made over 1000 years ago.  It’s made of olive oil and laurel berry oils, a soap whose origins are reported to be the vegetable-oil-carafe-on-table-151x151Syrian city of Aleppo and go back in history at least a thousand years, even further in legend. Popular reports have Aleppo soap being used by Cleopatra and Queen Zenobia of Syria.  I’ll talk about Aleppo Soap in another post, soon to come.

That’s not the purpose of my post though….my purpose it to help you make some All Natural Castile Soap for yourself.   If you’d like to PURCHASE All Natural Castile Soap please BUY IT HERE

So what is Castile Soap and why is it so popular?

It’s my understanding that this type of soap is the mildest form of soap available to us.  “Castile” means something very specific. Not only does it refer to the area of Spain where the soap reportedly originated, it also means soap made with 100% pure extra-virgin olive oil.  Unadulterated and Pure Extra Virgin Olive Oil of the highest possible quality.  The origins are actually hotly debated, with many claiming the origins the world over, this will never change.

Now I recognise that not everyone has an olive grove on their doorstep, however to do this soap justice it is best made with the highest quality Extra Virgin Olive Oil that you can get your hands on.  Many soapmakers say that a soap made with over 70% Olive Oil is just as good and make reference that it’s a ‘Castile Soap’, however I really encourage those that want to make the ‘real thing’ to use 100% Extra Virgin Olive Oil.  The results will please you beyond belief.

Natural Castile Soap boasts some unmatched qualities when it comes to bathing pleasure…’s mild, it’s a very hard soap & it’s reported to be one of the best soaps for people that have problematic skin conditions including the elderly, babies and also anyone that just likes to use ‘plain soap’ over the ‘other types’ of soap available on the market.

If you’ve never made soap before, please check out my earlier post on How to Make Soap, paying particular attention to the safety precautions that I speak of.  Soap Making is very rewarding and I challenge you to try it out, you’ll be so chuffed with yourself, that you’ve made something so useful and beautiful.

So, Natural Castile Soap requires the following ingredients.


500gms Extra Virgin Olive Oil (the highest quality available to you)

97gms Demineralised Water

64gms Sodium Hydroxide (Caustic Soda)

You will need to prepare a mould for your soap, prior to making your soap.  Your mould needs to be able to hold 660gms of soap batter, or if using individual moulds make sure you’ve enough for the job.  A waxed 1 Ltr milk carton makes a great soap log that you can cut up into bars after your soap has been made.



Weigh your EV Olive Oil into a stainless steel saucepan and gently warm to 50 degrees Celsius

Weigh your Demineralised Water into a stainless steel bowl (use chilled water)

Weigh your Sodium Hydroxide into a disposable cup, yoghurt container or something else that you can dispose of.

Gently pour the Sodium Hydroxide Crystals into the Chilled Water (always pour the crystals into the water and never the other way around) and mix to combine ensuring that the crystals dissolve into the water.  It will immediately heat and produce some gases it will also be a little cloudy.  Do not breathe these gases and keep your safety apparatus on during the process.  Allow the mixture to cool down under 50 degrees Celsius.  This mixture is called lye.

Once you have your lye mixed and it’s cooled, balance the temperature of the oil to be similar and at approximately 50 degrees celsius.

Once temps are similar (say within 5 degrees celsius of each other) gently pour the lye into the oils.

Mix the combined oils and lye to emulsion and continue to mix until you see that it has changed consistency, to that of a ‘light custard’ or for want of a better description a ‘pancake mix’ – this is called ‘Trace’.  Trace essentially means that when your stirring tool is lifted out of the batter you can draw ‘trace’ lines on top of the mixture before it subsides back down into the mixture.  You’ll find that whilst you can do this with a whisk by hand, a stick mixer makes a much better job of it in so much less time.  This particular recipe uses less water to help you achieve trace quicker.  When your mixture has traced, this is when your soap is ready for any additives that you’d like to include, if any.

We’re making a Natural Pure Castile Soap, with no additives on this occasion.  Now we’re all ready to pour this beautiful castile soap into our awaiting moulds of choice that you prepared earlier.  Waste no time pouring your soap into the moulds.  If you are a bit slow your soap will continue to thicken and you’ll be plopping it into your moulds instead.

Make sure you choose moulds that will contain your mixture, for this recipe you’ll need one that will hold approximately 660gms of soap batter.

Mould choices?  Specialty Soap Moulds can be used however to help you with some other ideas, try a lined gift box?  If lining a cardboard box or gift box, use waxed baking paper.  The kind that you can use in your oven has a waxed coating that will also make your mould somewhat waterproof.  You could also use a 1 Ltr wax coated cardboard milk carton, which you can tear off and throw away after use (these won’t need to be lined).  Silicone moulds do not need to be lined.

Now that your soap is in the mould, you can wrap it up, mould and all, in a couple of towels placing a little plastic between the towels and your soap and help it to stay warm, allowing it to go into a full gel state and continue on to  saponification.  This will happen in your mould if you just help it to stay warm as long as possible.

If you are confident you can place your mould (uncovered), onto a baking tray and pop it into a preheated oven, that has been preheated to 50 degrees celsius, turning off your oven when you put your soap mould in.  The residual heat in the oven will ensure your soap reaches full gel, without doubt.  Leave your soap in the oven until the oven is completely cold, overnight is best.  Remember to turn your oven off after you put your soap in, we don’t want to scorch it?  This is called Cold Process, Oven Process Soap or CPOP for short.

If you are a more experienced soap maker, you’ll know that a ‘full gel’ will help to produce a very hard bar of soap quicker than allowing it to reach saponification in it’s own good time.  Forcing or helping your soap to reach ‘full gel’ will in my opinion make a harder and more stable soap much quicker and allow any natural colourants to reach full potential.  Olive Oil Soaps are known do be very dense and as they already take plenty of time to ‘saponify’ it’s well worth ensuring that they’re off to a good start straight away, by doing the things that I’m saying above.

Extra Notes –

  • This recipe as written above makes use of a 1.5 : 1 water : lye ratio, which will help the soap set faster
  • The recipe makes approximately 5 standard sized soap bars weighing about 110gms each after cure
  • The total weight of batter is 660gms, with a 5% superfat included in the recipe, which just means that I’ve used a little less sodium hydroxide than the olive oil requires to saponify into soap.  This is known to produce a more nourishing/moisturising soap.
  • You can certainly add any additives to your soap just before pouring into your mould such as essential oil at between 1-3% of the weight of olive oil used.
  • If you’d like to make a larger batch, simply multiply all ingredients listed above accordingly.  Mind you’ll need a bigger soap mould or moulds.


The recipe given above is how I make All Natural Castile Soap, have a go yourself and if I can assist please contact me or comment below and I will answer as soon as I can.  The image below is Castile Soap made with Fresh Goats Milk, simply replace the water content with Frozen Milk and continue with the recipe as usual.  You’re in for a real treat.

Goat Milk Handmade Soap Workshop
Castile Goat Milk Soap