Simple Castile Soap Recipe: how to make olive oil soap with just three ingredients

Instructions for making a natural Castile soap recipe with the simplest of ingredients. Also includes tips on how to harden it up and cure olive oil soap faster.

So many soap recipes call for four or more oils, lots of additives, and enough essential oil to bankrupt you. Fortunately, making pure and natural handmade soap can be as simple as just three readily available ingredients. Olive oil soap, or Castile soap, is one of the most traditional types you can make. However, if you’ve made cold-process soap before you might be a little alarmed by the time that some of the steps taken. Don’t worry though, I’m here to guide you through making some of the most skin-loving soap you’ll ever use.

Olive oil soap bars lined up on a wash cloth
Castile soap made with extra virgin olive oil is mild and a warm yellow color

Soap Making Oils

Technically you can use any oil to make soap but each one has a different soap making property. Coconut creates hard bars with fluffy lather, Sunflower oil creates softer, conditioning bars and castor oil helps to stabilize lather. There are few single oils that make a really good batch of soap though and that’s why so many recipes call for a mixture of lots of different ones. Too much coconut oil and your bars might be drying, too much castor oil and they might be sticky.

Two of the exceptions to this are tallow soap and pure olive oil soap. In the case of olive oil soap, you can use extra virgin olive oil or Pomace olive oil to make it. The former will be more expensive but will be higher quality and more natural product. You can read more about what pomace olive oil is and how it’s extracted here.

a hand holding a bar of yellow olive oil soap over a basin. Creamy lather with few bubbles are on the bar
The lather of pure olive oil soap is very creamy but also very sensitive

About Castile Soap

On its own, olive oil can make a good hard bar that’s sensitive, nourishing, and doesn’t over-dry your skin. It has quite a unique lather though that I’ll call creamy but you’ll hear others call slimy. It lacks the big fluffy bubbles that coconut oil or castor oil can give but in all honesty, I love it. No other soap feels quite as gentle as a bar made out of extra virgin olive oil.

It’s not entirely clear when soap was invented but some of the earliest we know of was made of olive oil and laurel oil. Called Aleppo soap, these bars were introduced (or re-introduced) to Europe after the Crusades. Laurel oil wasn’t readily accessible so soap makers in the Castile region of Spain started making soap without it. Hence, the invention of pure olive oil soap.

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a bar of olive oil soap popped out of a pink silicone mould. It's sitting on top while all the other bars are still inside
This castile soap recipe needs at least 48 hours in the mold and up to four days if Sodium lactate isn’t used

Making Olive Oil Soap

I mentioned before that making olive oil soap could be a bit alarming for soap makers. That’s because it takes longer for it to come to ‘Trace’, longer for it to harden in the mold, and longer for it to cure. If you prepare yourself for that, then making it is easy.

There are a couple of steps that I’ve woven into this recipe that should help with this time issue. We’ll be using less water than in typical soap making recipes and the optional ingredient sodium lactate helps to harden bars. Ordinary table salt can help with this too but Sodium lactate is far more dependable. Just be careful that you don’t use too much sodium lactate or it can cause your soap to go crumbly.

Using less water than what’s typical, is called using a water discount. In soap does a few things, including help stop soda ash from forming and speeding up the time it takes your soap to ‘Trace’. It also reduces your cure time since there’s less water that needs to evaporate out of the bars. In this castile soap recipe, using a water discount will be helpful on all counts.

Another thing that will help speed up trace and to create slightly harder bars is to use olive oil pomace. It’s second-grade olive oil, cheaper than extra virgin olive oil, and often found in bulk food stores. Ensure that the olive oil is well in-date when purchasing from food suppliers, and if it comes in metal tins, you can use them to create these gorgeous succulent planters.

Runny yellow soap batter dripping from a spatula and back into the pan
Castile soap takes much longer to come to ‘Trace’ than other soap recipes

Natural Soap Making for Beginners

If you’re new to making natural handmade soap, you should read my four-part series on natural soap making. It gives a good introduction to what to expect from ingredients, equipment, cold-process soap recipes, and the soap making process.

1. Ingredients
2. Equipment & Safety
3. Basic Recipes and Formulating Your Own
4. The Soap Making Process: Make, Mould, and Cure

Simple Castile Soap Recipe

Makes a 1 lb or 454-gram batch which is exactly six bars if you use this soap mold. Please make sure that you are aware of all the safety-measures you need to take when handling lye and making soap. This soap has a 5% superfat.

For more experienced soap makers: you can make this recipe at just above room temperature if you choose. Soaping at room temperature gives you the color of bars that you’ll see in this recipe’s photos but it will slow down your Trace time. If you’re a beginner, I’d recommend that you stick with the slightly higher temperature given below.

Simple Castile Soap Recipe

Lovely Greens
Pure olive oil soap recipe with steps that harden up the bars quicker than other castile soap recipes. Technical information: 1lb / 454g batch -- 5% superfat -- 35.7% lye solution.
The two steps that will help your batch of castile soap to harden and cure quicker are using sodium lactate and a water discount. The water discount is worked into this recipe for you, though if you're experienced you could look into discounting it further.
5 from 14 votes
Prep Time 30 mins
Cook Time 30 mins
Curing time 28 d
Total Time 1 hr
Servings 5 bars


Lye water

Liquid oils

After Trace


Prepare your work station

  • Prepare your workstation with your tools and equipment, and have your mold at the ready. Put on rubber gloves, eye protection, and an apron. Carefully pre-measure the ingredients. The olive oil can go in a small stainless steel pan, the water into a heat-proof jug, and the lye in another container. If you're using it, pre-measure the essential oil into its own small dish or ramekin.
  • Although listed as 'optional', sodium lactate is useful in hardening all soap recipes, especially softer soap like this castile soap recipe. It's available as a powder or in liquid form and if you're using the liquid form, you'll need one teaspoon of it. If you're using the powder form, use only half a teaspoon and dilute it in one Tablespoon of the water amount you've measured for the lye. Do this before you begin, and mix the powder and water into its own small dish.

Make the Lye Solution

  • Make your lye solution in a well-ventilated area, preferably outdoors, by an open window, or under a kitchen extractor that ventilates to the outdoors.
    With your goggles and gloves on, pour the lye onto the water and stir it in. Keep your face away from the steam that comes up and be prepared for the water to get very hot. Stir until the lye is completely dissolved and then set the jug in a basin of water to cool down. You want it to cool to 100°F / 38°C and can begin warming the olive oil as it cools.
  • Add the sodium lactate to the lye solution after it's cooled below 130°F / 54°C

Warm the olive oil

  • Warm the olive oil in its pan on low until it reaches about 100°F / 38°C. When both the oil and the lye solution are within about five degrees of one another, it's time to mix. Take your pan off the heat and proceed to the next step.

Stick blending to Trace

  • Pour the lye solution through a fine-mesh strainer and into the olive oil in the pan. Stir it together and then use an immersion blender (stick blender) to bring it to 'trace'. Trace is when the soap begins thickening up to a warm and thin custard-like consistency.
  • Using the stick blender to emulsify small batches of soap can be a little more tricky than larger batches. I recommend that you first dip your immersion blender into the pan and with it turned off, stir the mixture. Next, bring it to the center of the pan, and with both your hands, hold it on the bottom of the pan and blitz it for just a couple seconds. Turn it off and stir the soap batter, using the blender as a spoon. Repeat until the mixture thickens up to 'Trace'.
  • You've hit 'Trace' when you can drizzle some of the soap batter onto the surface of your soap and it leaves a trail. I prefer working at a very light trace since it settles nicely into molds. A thicker traced soap can literally be spooned up and plopped into containers. If you're a beginner, aim for somewhere in the middle.
  • Just to clarify, in small batches of soap I advise that the immersion blender is not moving while you have it turned on. Hold it down against the bottom of the pan and turn on to pulse. Only stir when the device is off, as stirring while it is on will create air bubbles and kick up caustic soap batter.
    I've placed a video at the bottom of this piece to show you the technique I use for using the stick blender. The recipe for the video is one I've shared showing how to use Cambrian Blue Clay to naturally color soap. I use short and controlled bursts of stick blending with gentle stirring.

Molding and Curing

  • When your soap is at trace, stir in the essential oil if you're using it (here's further information on other essential oils to use) and then pour the soap batter into molds. Leave uncovered and at room temperature or pop it in the fridge overnight if you wish. Leave the soap in the molds for at least 48 hours if not up to seven days. Handmade Castile soap can take time to firm up. If in doubt, just leave it a bit longer.
  • When the soap has hardened, pop it out of the molds and cure it. Space the bars out on wax paper / grease-proof paper someplace airy, dim, and room-temperature. This will allow the water that's left in the bars to gently evaporate out. There's detailed information on how to cure and store soap in this piece.
    Thanks to the water discount we used in making the lye solution, your cure time is only four weeks. Using a more standard amount of water in a Castile soap recipe can make the cure time more like six to eight weeks.
  • Once made, your castile soap will have a shelf-life of up to two years. Check the oil bottle that you're using though -- the best-by date on the olive oil bottle is the best-by date of your soap. If your handmade soap is destined as gifts, check out these eco-friendly soap packaging ideas.


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Recipe and instructions for making natural Castile soap with the simplest of ingredients. Also includes tips on how to harden it up and cure olive oil soap faster #lovelygreens #soapmaking #soaprecipe #castilesoap

Customizing Castile Soap

If you’ve ever traveled to the open markets in the south of France, Italy, or Spain you’ll have seen lots of Castile soap. Most of it is actually Bastile, olive oil mixed with other oils to improve lather, but almost all of it is colored and scented. You can make your castile soap as colorful and as lovely scented as you’d like.

You can literally make this recipe with just three ingredients if you choose — water, lye, and olive oil. The optional lavender essential oil will give it a beautiful floral scent and the sodium lactate or salt helps to harden the bars. If you’d like to be more artistic with these bars I’ve collected dozens of different ideas for you in my piece How to Naturally Color Handmade Soap.

Keep in mind that the natural color of this soap is a light yellow and that can impact the final color of your bars. Depending on the oil you use, you may find that your soap cures to a bright white color. You can also use different essential oils to scent it and my guide for how much you can use is over here.

If you’re looking for even more soap making recipes and ideas, have a browse through my recipes. This simple Castile soap recipe is just the tip of the iceberg.

Recipe and instructions for making natural Castile soap with the simplest of ingredients. Also includes tips on how to harden it up and cure olive oil soap faster #lovelygreens #soapmaking #soaprecipe #castilesoap


  1. Hi Tanya,
    Thank you so much for your blog and recipies! I want to start to make soup at home and your blog is full of inspiration and is being of great help. I have one question on this recipie. Can sodium lactate be substituted by sodium chloride? Or its better to dont use any other additive if sodium lactate in not available? Thank you so much for all the sharing :-)

  2. I’ve never made soap before but had an interest of late in making soap with mosquito-repelling essential oils. In reading through the various comments regarding volcanos, it would appear that, at least in this cold method, incomplete saponification is very possible. In the volcano episodes described, a higher temperature would accelerate saponification leading to rapid heat generation and essentially boiling the batch. My only question is: does this recipe produce pH-neutral soap if carried out as directed? Is there any reason to adjust the pH to 7 before it’s too late?

    1. Just make some soap Doug :) Don’t worry about the extremely rare volcano, mosquito-repelling essential oils (they don’t really work in soap), or creating neutral pH soap, which is not possible.

  3. 5 stars
    I have been making this recipe for a few years. I am allergic to perfume and have sensitive skin. This is gentle on my skin and I can make it perfume free.

  4. 5 stars
    Thank you for this recipe!
    Newbie question: I would like to use a 30% w/w sodium hydroxide solution I bought to make this soap. Because this solution is 30% lye and 70% water, is it already at the correct ratio of water and lye by itself? It looks to me that it is already at the recommended ratio of 2.3 parts water to 1 part lye. Or do I still need to add the extra distilled water?

    Looking forward to your answer, thank you!

    1. Hi Ludovic, this soap is already very soft due to it being all olive oil. I would not recommend any more water than a 33% solution. It’s a standard ratio of lye to water that many soap makers use for all of their recipes. The best way to remember how to make it is to simply double the amount of lye to get the distilled water amount.

  5. Hi! I’m seeing for the castile recipe, you had the ingredients in oz and grams. I’m seeing 2.05 oz NaOH was equivalent to 58g. What density did you use to calculate this?

  6. Hi I am trying to make soap but something keeps going wrong, my question is, when I am weighing my oils, do I have to include the weight of the container that I am measuring in?

    For example if the recipe calls for 22 oz of oil, and the container weighs 2 ozs, when my scale says 24 ozs, will that be correct for the recipe that calls for 22 ozs of the oils?

    1. Hi Anganie, your scale should have a tare button, or function. Place your bowl on the scale and press tare and it will reset the scale to zero. That way you can weigh ingredients without the scale working the weight of the container in. Sometimes the tare button is also the power button or another button on the scale.

  7. 5 stars
    HI Tanya,

    I’m about to try making soap for the first time! Thanks for the inspiration. Out of curiosity, I’m wondering if you’ve ever tried making shampoo before? Seems like a natural extension of the soap and skin care products you make.

    Thanks so much!

    1. Hi Ellen and I’ve had quite a few people ask this before. I don’t make shampoo bars (or share recipes) because no matter how you go about it, cold-process soap ends up with a very alkaline pH. It’s fine for our skin, but it can make our hair very brittle as well as feel like a tangled bird’s nest. Some people rinse their hair afterward with apple cider vinegar to try to acidify the pH again but if you don’t, your hair can be ruined. People who are most familiar with shampoo bars don’t realize that the best ones are not true soap at all but solid detergents — synthetic hair cleansing bars. They’re a good plastic-free and travel-friendly option, but other than that, not any better than conventional liquid shampoo/conditioner.

  8. Hi thanks for the recipe. This is my first time making soap so I’m a total newbie 😀I followed the recipe except for heating up the olive oil. And it seemed to have worked. Just wondering why the olive oil needs to be heated? Is it ok that I did not heat up the oil? Thanks

    1. Hi LT, it’s just so that the temperature of the oil is comparable to the temperature of the lye solution. It helps the soap to trace a little quicker, and also, if there’s a big temperature difference, then sometimes odd things happen. Visual effects mainly in the case of castile soap. If you’d like to make this recipe at room temperature, feel free, but try to cool the lye solution down to room temperature before you mix.

  9. Hi, great recipe. I am about to try it. I have been struggling with powdery lye on the surface of my dried olive oil soap. Is the recipe suitable to multiply by 4? I have loaf size molds.

    1. Hi Mary Anne, what you’re experiencing is called ‘soda ash’ and you can avoid it by water-discounting (using less than full water) and spraying the surface of your soap with rubbing alcohol after you pour it. As for quadrupling the recipe — yes of course, and by all means.

    2. Hello, I have never made soap at all, so have been looking for some simple nice recipes to try out, and olive oil appeals to me…However, from looking at different recipes I am starting to think that it is quite expensive to do . I assumed at first that people made their own soap so as to buy a more luxurious product would be cheaper…but am I correct in thinking, the prime reason is that its a ‘hobby’ ??

      1. The typical bar of soap that you buy from a shop or farmers’ market costs 4x more than the materials needed to make it. However, there are start-up costs involved in soap making at home so if you’re only planning on making a single batch and never making soap again, you could end up wasting money.

  10. Thank you very much for all you do and for taking the time to post all these for other people to learn and improve their skills and knowledge. God bless you!

  11. I made this is a silicone mold loaf and cut it after it was hard. It crumbled to pieces.
    What did I do wrong?!

    1. It’s really very hard to know but I suspect you used the incorrect amount of ingredients. Or possibly you added something that wasn’t in the recipe? Sugars like milk and honey can often lead to crumbly soap as can incorrect amounts of lye. There are a lot of steps in soapmaking and it’s easy to miss things when making soap as a beginner. Try again, and I recommend that you use one of the beginner soap recipes I have here on Lovely Greens. Here are a few

  12. 5 stars
    Thank you for the recipe!!
    Can this recipe be used in crock pot hot process to speed up curing? If so, how long would you recommend curing?

    1. Even hot process soap needs curing, although it’s just 2-3 weeks opposed to 4-6 with cold process. Curing has less to do with lye and saponification, and more about allowing the water content in the soap to evaporate out. Also, most cold-process soap recipes can be used for hot process too.

  13. 5 stars
    Hi. I too made this recipe as my first ever batch of soap a couple of weeks ago. I was scared of using lye so it took a bit of courage but I have found that I love soap making, thank you 😀 I fragranced mine with almond milk fragrance & it still smells wonderful as it is curing. The soap bars feel really smooth and lovely. I can’t wait to try them! I have just finished a batch of your lemongrass soap. I will work my way through more of your recipes 😀 Thanks again for the recipes and inspiration 😀

  14. 5 stars
    Thank you for this lovely and easy recipe for soap. I have now made my first batch of soap ever, and the soaps seems to cure nicely. I can’t wait for four weeks to pass so I can try the soaps. I will try a different recipe soon. This is a great page for soap making, one of the best I have found.

  15. Hello! I have made this soap recipe before (and plenty other cold-process soap recipes too) with success but my latest attempt with this recipe ended in a bubbling mixture. I wish there was a way to attached an image. I managed to get the mixture to achieve trace just fine, poured it in a mold, and then was covering it with plastic wrap when it suddenly started bubbling and foaming. Do you happen to know why this occurred? Thanks!

    1. This is the rare and terrifying soap volcano! It can happen with any soap recipe and usually when the temperatures are too hot. It could be the soaping temperature or the soaping temperature combined with exterior/air temperature.

      1. I also had this scary bubbling soap monster, and believe it might have been due to a few grains of caustic soda not properly dissolved. The resulting soap was not pretty as I had to scoop it up and force it into a tray, but its performance was the best ever. My husband even asked if I could do exactly the same soap again, but it is not easy to reproduce this mistake. Is this a hot method soap Tanya? In any case, you always learn so much from the mistakes.

        1. It’s temperature that causes soap volcanos and you can avoid it happening by keeping ambient and soap temperatures stable/low. But even then, volcanos are quite rare and it’s only ever happened to me once. As you say, it’s very hard to replicate but can be a little scary when it does happen. The recipe and instructions for this cold-process soap recipe are in the piece :)

    1. I find that cold-process soap of any kind turns my hair into a bird’s nest. Most of the shampoo bars that people use aren’t true soap, but solid shampoo (detergent).

  16. Hi Tanya.
    I would like to make your Simple Castile soap with honey and oats. Could you please tell me how much and when to add honey and oats. This is my first time making soap and I would love to add honey and oats. Hope you can help.

    1. I’m looking to make 100% olive oil soap without lye water. Is this possible? I don’t mind if it takes time.

      Thanks ☺️

  17. Thanks for the recipe! 😊 This was my first time making soap. Large cracks have developed whilst setting in the mould and after 4 days the soap seems crumbly. What has caused this?

    1. Cracks sometimes happen because of soaping at high temperatures or incorrect amounts of lye. Try making the recipe again, double-checking amounts, that the ingredients are correct (double-check your lye), and that the temps are all good. I’ll bet it was just some little thing that you’ll catch the second time round :)

  18. 5 stars
    Hi, Tanya…Thanks so much for this Castile soap recipe. I have wanted to try to make soap for some time and finally took the plunge. My first batch came out great thanks to you. I scented it with lemon and sage essential oils. Popped it out of the silicone molds the next day and as I am sure many first timers have done , used it in the shower that day. It was great! The other 13 bars will be cured! Thanks again!

  19. Help! I’ve just started my first attempt – I had everything ready and prepped and practiced – I poured the lye and salt, carefully, into the water – all ready with my gloves and mask and goggles . . . . . Nothing happened! No steam or fumes. I stirred and stirred it because the lye is in big crystals. The outside of the jug did feel warm, but still no other reactions. I couldn’t dissolve the crystals, however much I stirred. So I abandoned it because I don’t want to waste a pint of good olive oil. Ok, so what do you think? I am actually in Bulgaria and I’ve tried to translate what’s on the caustic soda container to see if it’s mixed with something else. It says ‘for soap, 1 kilo crystals to 3 kilos fat’. That’s a higher ratio of lye to fat than I’m using. Maybe if I try to break up the crystals it’ll work? Any ideas? Thank you

    1. Any lye container that includes that information does not sound legit. Try to get ordinary caustic soda that’s 99% sodium hydroxide. Available as a drain cleaner in some places. Just make sure it doesn’t have anything else added.

  20. Hi Tanya,
    I am preparing to make this Castille soap this weekend. It will be the first time I use sodium lactate. Can you tell me if the 1 teaspoon of sodium lactate of you receipe is some powder or liquid. I am asking because I purchased some sodium lactate on line and what I received was liquid, already dissolved, in a bottle of 100 ml. It is written on the bottle that it contains 60% of sodium lactate. If your receipe calls for powdered sodium lactate, would you know how much it means when already disolved in liquid?
    Thank you very much in advance.

  21. 5 stars
    Hi Tanya!
    Thank you for that lovely recipe. This was my first batch of soap and it came out just perfectly. I love the smell and that it’s a 100% olive oil soap. Can’t wait to finally try it!
    I love your websites and all of your videos! Next year I definitely add a soap & skin care garden to my veg patch.
    Saludos to the isle of man

  22. 5 stars
    Hi Tanya, I love your site! I want to say you that I did my first soap! I followed carefully your instructions and my first soap is already done, it looks perfect! I have checked many recipes online but you explain very well why to make water discount for castile soap and why to add salt and the result is excellent. Thank you for the recipe and greetings from Bulgaria! ❤️❤️❤️

  23. Hi Tanya,
    My first batch was beautiful and everyone loved it.
    I have made a second batch and poured beautifully, then all of a sudden it erupted like a volcano.
    It reminded of making honeycomb.
    What did I do wrong?
    I measured correctly.

    1. Volcanoing soap is rare but it does happen on occasion. It mainly happens when the soap overheats. Keep an eye on the temperatures in your next batch and also where you leave your soap to harden up. If it’s someplace that’s too warm (near a radiator, sunny window, etc) then this can overheat your soap.

      1. Hi Tanya,
        Thank you for your reply.
        I have kept the volcano soap, is there anything I can do with it or
        should I throw it out?
        Thanks again
        Kind Regards

        1. Hello Tanya,
          Thank you for your reply.
          You must think me very rude but I have only just seen your reply.
          Stay safe

  24. If I did the math correctly, your recipe of 2.05 oz lye to 3.7oz water is a 55% lye solution. I believe I’ve read that you shouldn’t use greater than 50% lye. I’m new to this, but am adjusting the recipe to make it a 40% lye solution.

  25. Hi thank you for sharing this recipe, I have two questions.

    1. What is the water percentage for this recipe
    2. Can I double it?


  26. 5 stars

    I followed this recipe but omitted the salt and the lavender ( i also forgot to strain my lye) but it came out beautifully! It’s even white colour. The only thing is, I’m conflicted as everyone is telling me to let it cure for 6 months minimum before using it!

    Do i really need to wait that long or will the 6 weeks suffice?

  27. Hi Tanya, loving this recipe. Just wanted to say that it would be useful to have a print friendly option, I don’t have an iPad so am reliant on printed notes :-)

  28. Hi Tanya! Soo excited to finally find something complete with regard to castile soap. This will be my very 1st batch and looking forward to a great result. Just one question, will pure olive oil (grade a) instead of extra virgin olive oil be ok to use? Thank you so much in advance.

    P.s. I am new subbie to your YB account too. 😍

  29. I have a couple of white bits left in each bar of Castile Soap after two weeks – please can you help?

    Best regards

  30. I enjoyed making this soap but my batch was small and I want to yield more. Can I just multiply the measurements by 2 or 3?Is that ok to do? Don’t want my soap to be too lye heavy or have other issues.

  31. Hi Tanya

    I see you have written that there are two oils which can be used in cold process soap making, without having to add other oils, olive oil and tallow.
    Could I replace tallow with lard?
    Kind regards

  32. i am new to soap making this was my first attempt . when mixing the lye i found i still had little bits at the bottom . will my soap be safe to use . i did pour this in a sieve but bits still went in my soap i followed your recipe. i also notice you state leave soap uncovered . every recipe i have read say to wrap in towel to keep warm . can you tell me why to keep uncovered. my lye in fresh and got from a soap making site

    1. Hi Christine, I’m trying to understand what happened but I’m not sure. A sieve is like fine mesh, not a colander if that’s what you used? Sieves catch all the things. Also, you saw the bits before you started stick blending it? If that happens again, sieve the oil and lye mixture again to get them out. If those bits were undissolved lye then there’s a possibility of lye pockets forming in your bars.

      Leaving soap uncovered means that the soap will not go through Gel state. It keeps the soap light coloured.

  33. Hi, this will be my first attempt at soap making. Is this a daft question…what is the superfat for this recipe?

  34. Hi
    This didn’t work so well for me. I read elsewhere that castile can take longer to firm up so I left it in the mould for three days. Too long – it was very hard when I got it out and it cracked and crumbled. I will try again but maybe with a higher water content.

    1. Sorry to hear of your issues. Cracking and crumbling in many cases indicate issues with temperature and/or the lye amount. Clays can also cause cracking but shouldn’t be the issue in this case. Just be aware that if you add extra water to this recipe then it may take quite a long time to firm up. A week or two even.

    2. I am sooo happy to find your site. It’s so informative. I already made my first soap with honey last year and we are down to the last piece and now i want to make more.
      Can i substitute palm oil with more coconut oil?

  35. This is a great beginner’s recipe for new soap makers! I make Bastile soaps myself, but only because I live in a humid place where pure Castile soap would take almost 9 mos to cure!
    I’d like to make one observation though. If you use sodium lactate or salt to the lye solution, it’s best to dissolve either in the water BEFORE you add the lye, otherwise neither will dissolve properly.
    May I add something else? If you have yogurt, preferably plain full fat or full cream, you can add 2 ounces as water replacement at trace for a harder bar. It’s a good replacement for the salt or sodium lactate. Just be aware that after adding it the soap batter will immediately become more fluid. It won’t affect the time it will take to un-mold but overall, the bar will become harder sooner.
    Thanks for a great Castile soap recipe!!

  36. 5 stars
    I made my first batch of soap followed you recipe exactly. They look and smell beautiful. Cant wait to use them. Thanks a lot.

  37. Hi. Through your posting here I’ve made my first batch of olive oil soap!
    One thing didn’t quite go right.
    I had a nice light trace.. I added the lavender oil… and mixed it in… It immediately turned into a very thick batter that wouldn’t pour.. kind of like a paste.

    I see in your post you say to stir it in… I used the stick blender and I’m wondering if that extra agitation caused the problem.
    In any case, I was able to get the molds filled… We’ll see how it turns out.

    1. My guess is that your lavender essential oil is actually a fragrance oil. Fragrance oils are often the culprit when a batch ‘accelerates’ and seizes in the pan as you describe. Check the label and if it is fragrance oil make sure that it’s skin safe. Some are only made for candles and can cause skin irritation. If you want to make natural soap, only use essential oils. It will be clearly stated on the bottle.

      1. Yes… I bought lavender essential oil. But see in the reviews people saying it seizes soap. I’ll look at getting oil that’s known good for soap making.

          1. I just made a batch using the lavender oil you link to in your post. It worked perfectly! It also has a nicer smell than the original oil I tried.

  38. Hi 😊
    This recipie was my first ever attempt at soap making. I forgot to add the salt but that’s cool! I also added some lemon zest and poppy seeds to change things up and help the citrus scent from the eo stay in. All went great, after 4 days I unmoulded but now 3 days on from that the soaps (they are little ones) have started cracking, is there any reason from my additions that could have done this? I gather they will still be usable after curing, just not as pretty!
    Thank you 😊 x

    1. How strange. Usually soap will crack when there are too many hard oils used (so not in this case), if too much clay was used (no clay in this recipe), the soaping temperature was too high (you’ll need to check your notes), or the measurement of lye was wrong. In the latter case, you can test the pH to find out if it is lye-heavy. I’d do that if you can before using it on your skin just to avoid any complications.

      My advice: try making the batch again and see how it goes :)

      1. Hi

        Thank you for getting back to me! It could be a temp issue as I was using my mother’s old 1970s sweet thermometer as I was too impatient to wait for me laser gun, I bet it’s not as accurate as I would have liked! I’ll check the PH of the soap as well but if it’s just a looks thing, then I’ll make use of it instead of giving it away.



  39. Hi, I tried this recipe and the oil separated from the soap in the mold, I noticed this when I checked the soap after 24hours. Please how can I fix it?.. thanks

  40. You state “When your soap is at Trace, stir in the essential oil if you’re using it and then pour the soap into moulds.”

    I was taught that additives (essential oils, coloring, etc.) added to the base soap (while the lye is still active) is not a good idea, since the caustic lye will destroy most of the beneficial properties and the additives will not be at their best advantage. I was taught that the best time to add additives is during the milling process. Can you give your opinion on this?


    1. Does your original soap making source quote any proof? Adding essential oils after Trace ensures that they go in after the vast majority of saponification is complete. I don’t see how/why the essential oils would be affected at that point. In any case most soap makers do not make their soap, mill it, then add essential oils back in.

  41. Hi, I’ve been looking into different oils for soaps and wondered if I could use half EVOO and half sweet almond oil? Would I need to make any other adjustments? Thanks!

  42. Thank you for the recipe! I have not tried to make soap yet and I am thinking it’s because of the calculation and a lot of different oils that you usually find in recipes which intimidate me a bit. Funny, lye doesn’t intimidate me… Question for you; in step two you say to heat up the oil and then add the lye do you take the sauce pan of the heat at that point or do you leave the heat on until you have trace?


  43. dear Tanya, which recipe is safe for a new born baby’?
    I would like to be sure about the recipe
    can you help me in this matter?
    thank you very much
    Mirta, from argentina.

    1. A simple soap like this one would be good for gently cleansing sensitive skin. If you were making it specifically for your little one, I’d leave out the essential oil.

  44. Thank you so much for this recipe! My sister is allergic to coconut so I want to make her Castile soap. All your recipes turn out so well, so I am looking forward to trying this one. My favorite is your goats milk soap. I made another batch today for holiday gifts, coloring it with pink kaolin clay. Thank you for your site!


  46. Lovely recipe!
    Can we replace the olive oil with some other oil? Such as sesame or coconut oil which are more readily available in rural India…

    1. You can make 100% coconut oil soap BUT you need to superfat it at 20%. That means you need 20% more coconut oil than is needed for the lye to convert into soap. If you use less than this the soap will be very drying and only good for household cleaning.

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