Basic Slow Cooker Soap Recipe

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Slowcooker Crockpot Basic Soap Recipe with coconut oil and olive oil
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I’ve been fascinated with soap making for a long time. What was once a common household skill now seems like such a complicated process that many people simply buy soap instead. Unfortunately, many conventional soaps have additives, antibacterial ingredients and artificial fragrances.

Slow Cooker Soap Tutorial

I first started using homemade soap when I realized that it was the most cost effective way to get an all-natural soap.

I buy all ingredients in bulk so for under $10 I can make 12-18 big bars of organic soap. Store-bought alternatives cost 4-5 times that amount.

A Word About Lye

Many people are afraid to try recipes that use Lye, but I’ve found that much of this fear is based on misinformation.

Yes, Lye (or Sodium Hydroxide) is extremely dangerous by itself. It can cause skin damage, blindness (with eye contact) and death (if ingested). Lye in its pure form is something that can be very harmful and extreme caution should be used when using it in any way.

Lye is created through the electrolysis of sodium chloride (salt) and it creates an extremely alkaline substance. If added to water, it becomes sodium and hydroxyl ions and creates a strong exothermic (heat creating) reaction. Flashbacks to high school chemistry anyone?

Moving on…

When Lye is used in soap making, it is what is called a reagent, meaning it is used in a chemical reaction to create other substances. In soap making, a carefully measured water/lye mixture is blended with natural oils in a process called saponification. Lye is simply an agent used to create soap from oils and water.

There is no unreacted Lye remaining in properly made soap. If you’re considering making soap, definitely use extreme caution with unreacted lye and use a soap calculator to make sure you are using the correct ratio of water/lye/oils but don’t be afraid of this age old process.

Where to Find Lye: Some hardware stores carry Lye (sodium hydroxide) though many have stopped carrying it. I wasn’t able to find it at any of our four local hardware stores so I ordered this one online. If you have a local (not big brand) hardware store they might also be able to special order it for you.

Hot Process vs. Cold Process

As the name suggests, the difference between these types of processing is if heat is used or not. With both methods, a water/lye mixture is used and oils are used. The two are mixed together in the process of saponification.

With cold processing, the water/lye mixture is mixed with the oil mixture and the resulting mixture is poured into insulated molds.

Hot processing adds an additional step of “cooking” the mixture which speeds the saponification process and makes the soap ready to use in days instead of weeks. Both methods work and I’ve done both, but the hot process method is much faster.

Choosing Ingredients for Soap Making

Crock pot soap ingredientsThe advantage to making soap at home is that you can use high-quality organic ingredients and still get organic soap for much cheaper than store bought options.

In this basic recipe, I used organic Coconut Oil and organic Olive Oil, though any natural oils can be used. Use this Soap Calculator to figure out how much Lye and water are needed for whatever type of oils you want to use.

Really- the world is your oyster when it comes to picking ingredients but some popular and favorite ingredients are:

Once you’ve picked your ingredients, head over to the calculator and find out how much water and Lye you need.

For this specific recipe, I used an equal mix of olive oil and coconut oil, but just pure coconut oil can be used (like this great recipe from Mommypotamus) or just olive oil can be used. If just olive oil is used, you’ll have a pure castile soap (named after that region in Spain) which is very moisturizing but can take longer to cure.

Cocount Oil and Olive Oil soap

Gathering Equipment

How Soap should look before Turning off slowcookerI personally keep separate equipment to use for soap making. I found all of my equipment at a thrift store and keep it in the garage with the soap making ingredients.

Every source I’ve seen says that it is fine to use regular kitchen equipment for soap making as long as you wash it carefully afterward (see my notes at the bottom of this post on that). At the end of the process, you are just dealing with soap, so it isn’t toxic, but cleanup can be messy. To simplify, I just keep separate tools for soap making.

I have:

Slowcooker Crockpot Basic Soap Recipe with coconut oil and olive oil
4.25 from 66 votes

Slow Cooker Soap Recipe

This basic soap recipe uses coconut oil and olive oil and is made in a slow cooker. A simple and moisturizing recipe you can make at home!
Prep Time45 minutes
Active Time35 minutes
Resting Time1 day
Author: Katie Wells



  • Prepare your mold. Wood molds will need to be lined with freezer paper or wax paper. Silicone molds are ready to use as is. You can also use any box if you line it with freezer paper, wax paper, or a thick garbage bag. I’ve heard of people using empty Pringles containers, but haven’t tried it.
  • Make sure that your work area is clean, ventilated and that there are no children nearby. This is not a good recipe to let children help with since lye is caustic until mixed with water and oils.
  • Weigh out 16 ounces of olive oil and 16 ounces of melted coconut oil and pour them both into the slow cooker.
  • Turn on high just until the oils heat up and then reduce to low heat.
  • While oils are heating, carefully measure the lye and water separately. TIP: This is the only thing I ever use disposable plastic cups for. They don’t weigh anything on the scale so they make measuring easy. I keep three separate cups labeled “Water”, “Lye”, and “Oil” to use for this purpose only. I reuse them each time so they aren’t wasted and I don’t worry about anyone drinking out of them since we don’t usually use these types of cups.
  • Carefully take the cups with the measured water and lye outside or to a well ventilated area.
  • Pour the water into a quart size or larger glass jar.
  • With gloves and eye protection, slowly add the lye to the water. DO NOT ADD THE WATER TO THE LYE (this is really important).
  • Stir carefully with a metal spoon, making sure not to let the liquid come in direct contact with your body.
  • As you stir, the mixture will become white and cloudy and get really hot. Let this mixture sit for about 10 minutes to cool. It should become clear when it has cooled.
  • When the oils in the slow cooker have heated to about 120-130°F, slowly stir in the water and lye mixture.
  • Quickly rinse the container used for the water and lye mixture out in the sink. I rinse well and then re-rinse with white vinegar to make sure all the lye has been neutralized.
  • Use a stick blender to blend the mixture in the slow cooker for about 4-5 minutes or until it is opaque and starting to thicken.
  • Cover and keep the slow cooker heat on low to thicken. I set a timer for 15 minutes and check it every 15 minutes until it is ready. It will start to boil and bubble on the sides first. After about 35-55 minutes (depending on the slow cooker) it will be thick enough that the entire surface is bubbly and the sides have collapsed in.
  • Turn the heat off and remove the inner bowl of the slow cooker.
  • If you are going to use essential oils for scent, add them now. I added lavender and orange.
  • Quickly and carefully spoon the mixture into the prepared molds.
  • Cover the molds with parchment paper and set them in a cool, dry place.
  • After 24 hours, pop the soap out of the molds. It can be used right away, but I prefer to let it set for a few more days so that it lasts longer.


Clean-up Tips
As I mentioned, keeping separate tools for soap making simplifies the process since things don’t have to be cleaned enough for food use. I still clean all tools carefully with dishwashing soap and water and rinse with vinegar just to be sure.
Since we are making soap, I typically soak the crock from the slow cooker with all tools in it for 8+ hours to dissolve and use the soapy water to help clean all the tools.

Ever made soap? How did it go? Share your favorite recipe below in the comments!

This basic soap recipe uses coconut oil and olive oil and is made in a crockpot or slowcooker. A simple and moisturizing recipe you can make at home!

Katie Wells Avatar

About Katie Wells

Katie Wells, CTNC, MCHC, Founder of Wellness Mama and Co-founder of Wellnesse, has a background in research, journalism, and nutrition. As a mom of six, she turned to research and took health into her own hands to find answers to her health problems. is the culmination of her thousands of hours of research and all posts are medically reviewed and verified by the Wellness Mama research team. Katie is also the author of the bestselling books The Wellness Mama Cookbook and The Wellness Mama 5-Step Lifestyle Detox.


322 responses to “Basic Slow Cooker Soap Recipe”

  1. Monica Guokas Avatar
    Monica Guokas

    Just a little memory helper for you:
    Do as you oughta
    Add acid to wata

    That will help you if you over think things. LOL But you don’t want to do it wrong as it will spit the water/lye mix out at you if you add it the other way.

  2. Lindsay Avatar

    I just made this soap for the first time and when I poured the mixture into the molds it was clumpy on top. I though it would just set as the time went on but the top of the soap is not a clean straight look like yours in the picture. Did I do something wrong or is this just what it’s supposed to be? Maybe I cooked it too long? Any feedback is appreciated. I do love them anyway and will be making them again! Thanks for the recipe!

      1. Jodi Avatar

        I’ve been making my own soap for many years now and I use it for my homemade laundry detergent as well. It works great! Even for HE machines.

  3. Alton Avatar

    5 stars
    Hello Katie
    Can I use the ratios that you’ve used to change into a smaller amount. Will that affect the quality of the soap?
    Also I don’t have a crockpot, so what else Can I use?

  4. Melissa W. Avatar
    Melissa W.

    How much does this recipe yield? 3 pounds?
    Can this recipe be cut down by 1/3 to just make a pound?

  5. Cindy Avatar

    Can I infuse the olive oil with herbs before pouring into the crock pot?
    Can I Use coconut milk or goat’s milk or herbal tea instead of the water? (or – half water and half other liquid??)…… Christmas is 2 weeks away and I am dying to make this soap for my family! Thank you so much for your time and wonderful, wonderful website!!!

  6. Cathy Avatar

    My husband and I just made soap out of pig/ lard and olive oil, so far, so good. Its at it’s curing stage and it looks and smells great.

    1. Jason Avatar

      Hi, I actually have a few jars of rendered lard I made from some local hogs when they were processed in the fall. Please let me know how your soap turns out as i am ready to make some soap but never thought of using the lard.

      Thank you!!

      1. Emily Avatar

        I made soap from lard and olive oil too. Found the recipe on a different site but used the method on this blog post. Best soap EVER!!

  7. Amanda Avatar

    Hi Katie,
    I have been making a ton of your recipes and I love them all thank you! Is it possible to put the soap into cupcake papers (in a metal tin) so that it is has the cute crinkle edge ? Do the molds have to be silicone and if so why?
    Also, I have been making your “smooth lotion” for my daughter’s eczema but how much of the Essential oils do you put in? I am not sure if i am using too much or if Lavender just does not work well with Cocoa butter.
    Thanks again!

    1. Wellness Mama Avatar

      I think you could totally put the soap in the little papers! I use the molds because I have them, but I don’t see why it would not work. and I don’t think cocoa and lavender work too well myself. You might try adding a little peppermint in to help.

  8. Bobbi Avatar

    Katie, first off- you’re awesome. Never doubt that, even on your off “I’m a real person & need to rant” moments… That just makes you more awesome. Secondly, can I use a hand mixer instead of a stick mixer to mix the soap? Having 3 kids makes it a little hard to splurge on extras sometimes (though I did buy a scale since that seemed pertinent).

    1. Emily Avatar

      I bought an off brand el cheapo stick blender from Amazon for $14.00 with free shipping. TOTALLY worth it! (I’m also a mom to three, and we’re a one income family, so I totally get where you’re coming from!)

  9. sherry Avatar

    I am interested in knowing the approximate cost per bar… maybe a 3 oz. bar?
    I am looking for a cost-effective way to provide soap for Operation Christmas Child boxes.

  10. paula Avatar

    I too am wondering the crockpot/slow cooker size? How do i know the temp is 120-130? And finally, is the coconut oil measured when a liquid or solid? Is fractionated coconut oil ok to use?-although im sure expensive in big quantities. 😉 looking Girard to the answers so i can give soap making a try. Been sitting on the sidelines quite a while now. Looking forward to using your recipe. Thanks!

  11. Amy Avatar

    Just curious, but can this recipe be turned into a liquid soap instead of bars?

  12. Venus Avatar

    I have been making homemade soap for 2 years now. I love it. You can create a soap to satisfy your skin”s need. Homemade soap cleanse wonderfully with out toxins. Just try it you will be hooked. I like to make soap in the crockpot. You can use it quicker. Yet the cold process soap is quicker to make.

  13. Shauna Avatar

    I have extremely dry skin in the winter, and have been using Dove for years. Will this be moisturizing enough for me? If not, what are some good additions? Thank you so much for this post!!

    1. zack Avatar

      Slow cook the oil with cannabis leaves for 8-12 hours on low, run through a French press and follow the recipe..the cannbinoids will help hold moisture and act as a natural anti-inflamitory and pain reliever

  14. Karissa Avatar

    Does anyone have a good recipe for breast milk soap? I think it would be a good way to use my freezer supply.

    1. Randy Avatar

      Please contact your hopsital to see if they could use the milk first. Or a le leche league.

  15. carolyn Avatar

    Hello Katie!
    how big is this crok pot (the you have in the picture)? Do you think a 3qt would be enough ? Thanks a lot!

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