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. Lina Avatar

    There are two opinions about it. One says it’s ok (and I’m with that as any harmful chemicals are gone after the cooking), the other is totally against ever, ever, ever using that crock for food again.

    You will have to clean the pot thoroughly, that’s clear, and I would advice not using any fragrance oils for the soap still in the pot. Those are hard to get rid of and I wouldn’t want to eat a roast with flower aroma ;-).

    1. Emily Wells Avatar
      Emily Wells

      I have a crock pot that’s dedicated for soap making only. Even after rinsing it with hot water and vinegar and running it through the dishwasher, I still see a lot of white etching/scratches in the crock (it’s black and very visible). It’s probably fine to use for food, but I’d rather be safe than sorry!

  2. Ann Avatar

    I am SUPER excited to make this tomorrow! I’m even going to drop my 5yr old off at his grandmothers for a few hours so I don’t have to worry about him 🙂
    Question tho- I have an older crock pot that i’m planning on using…is it OK to make food items again in the pot after using it to make soap? Same with the immersion blender? I guess it might be a silly question, since it is SOAP in the end, but I wanted to make sure that if I need to set this crock pot aside for soap-making only, I’m prepared. Thank you!

      1. Kelly Johnon Avatar
        Kelly Johnon

        It just got crazy fluffy in the crockpot- I got nervous- haha. Seems to be setting great though.

  3. Jennifer Avatar

    5 stars
    I’m sorry if I have missed this question in the comments. But can I line my crockpot with aluminum foil and then still be able to use it for food or should I find an old crockpot? Also, can you add little honey to this to make a honey soap- about 2 tsps or 2 tbls? I love the smell of honey soap!

    1. Lina Avatar

      Please never, never, never use anything with aluminium when making soap as it reacts really badly with the lye and accordingly with the uncooked soap. Better find an old crockpot or if you can find those plastic crockpot liners use those.

      And yes, you can add a bit of honey after the cooking without problems (about 1 Tbls per 500g of your fats). The soap will feel sticky at first and needs a longer drying time, but it’s worth the wait.
      Also adding one Tbls of yoghurt or sour milk after the cooking makes putting the soap into the mold much easier as the soap batter gets a bit more fluid. Warm up the honey and/or yoghurt thorougly before adding so it doesn’t cool down your soap batter before it’s in the mold.

  4. Linda Avatar

    Five weeks ago I made my first batch of Patchouli scented soap. I put the oats in at the same time as the scent – once the lye/water and warmed oils had cooled to about 105 degrees and were being stirred together. I’m now using my soap and love the oats in it. I sprinkled some in the bottom of a container and it looks awesome and decorative. Can’t wait to make my second batch.

  5. Lisa Avatar

    5 stars
    Hi, thanks for the recipe 🙂 gearing myself up to making this soap (my first time) and I was wondering if anyone could advise me on whether or not I could add oats to the mixture? And at what point during the process? Any help would be greatly appreciated, thanks again xx

  6. Belinda D Avatar
    Belinda D

    This is awesome thanks for the post!

    Wondering if it’s possible to use something like coconut MILK for the soap and how I would alter the recipe to use??


  7. Chris Avatar

    5 stars
    Just wanted to say thank you for this recipe. I’ve made a fair bit of cold process soap, but this was my intro to hot process. Given the shorter interval between making and using, along with the ease of adding ingredients after saponification is complete, this may prove to be the new norm.

    The article might benefit from a more detailed description of how to tell when the soap is “done” (and photos?) I did some further research to determine this, but having never seen hot process before I really wasn’t sure if my soap fluffing up in the pot was normal or heralded catastrophe.

    Also, having noted an earlier comment about the “dangers” of olive oil when heated, and having subsequently read the link you provided, I thank you for providing good information and being well informed. The almost 200 my soap reached is way below the conservative smoke point of olive oil at 325, so I think my hands will be safe from spontaneous cancerification.

  8. Atiya Avatar

    5 stars
    I just took my soap out of the molds and I was horrified at how my pour was so crap-tastic. Maybe I have some questions. I think the first thing is tools: I have a stick whisk. It’s like the blender thing-er-ma-gigs but instead of that lovely double blade it’s well a whisk. This made my mixture really fluffy like fluffy egg white fluffy. This is wrong right? I didn’t have to pour at all instead I had this stuff that acted like from the box mashed potatoes. I think because of this I got really ugly (but nice smelling) bars of soap that have tons of pockets where I wasn’t smart enough to press down the fluffy soap into the mold. No go on the power whisking I guess? Anyway I used Lemon and Peppermint last my scent for these so my apartment smells awesome.

    It was a very fun project though and I think I will try again when my counter space is available.

    1. Lina Avatar

      You might want to try out if you didn’t make “floating soap”. The whisk certainly has beaten a lot of air into the soap, that’s why it looks funny. It’s still soap, though, even if it doesn’t look like you expected it. You may not want to gift it, but you’ll enjoy using it yourself, I’m sure.

      Get a cheap stick blender for future tries (but make sure not to overheat it while making the soap, switch to manual stirring with the stick blender when it starts to get warm) and it’ll work out better.

  9. Tasha Avatar

    4 stars
    I made this batch a couple of weeks ago and it was my first batch in a crock pot. I think cold process is easier and the bars that I made cold process are hard solid bars. When I tried this recipe, the soap came out amazing but soft and dissolves quickly. Especially with my three boys leaving it in the bottom of the tub which I try my hardest to prevent. What did I do wrong in this batch? My soap is too soft.

  10. Kristy Kaye Avatar
    Kristy Kaye

    5 stars
    I made 2 batches within 3 days and it all went very well. Thanks so much for the recipe and wonderful directions!!! My question is what we made…is it considered ca stile soap? If it isn’t can it be substituted for the same?

  11. Linda Avatar

    Question: My brother likes soaps with oatmeal – for a little scrubbing affect. Has anyone used this in this recipe? I’ve never made soap, and have a long list of things to purchase and have been putting it off for a couple years now. He loves patchoulli – so that will be my first scented soap. Wish me luck!

  12. Corinna Avatar


    you measure everything by weight. Don’t be afraid of the lye. Wear protection as recommended. You need to relax so you don’t drop it 🙂 Katie recommends up to 1 oz. I made the 4th batch with this recipe and have used 20-40 drops for a batch and you can smell it. I would not even add color. Don’t make it to complicated for the first time plus with the hot process you might not have time to add it or mess up your batch. The soap dries fast. I think the natural color would just be fine. I use a silicone form with little hearts to make samples and put the rest in a shoe box. There is not too much time to fill once the soap is ready in the slow cooker. Why don’t you just use nice colored little sachets to put the soap in. Sometimes they have them at the dollar tree. You might want to try a batch first to see how it works. Have fun!

    1. Emily Wells Avatar
      Emily Wells

      Oh my gosh oh my gosh oh my gosh!!!! okay, so I tried making soap for the first time the other night, and I am HOOKED!! I didn’t use your recipe posted above–I found a recipe at another site that contained lard, so I made that recipe, but followed your instructions for the hot process. (I wanted to try a “test” batch to make sure that I can actually do this, but I didn’t want to buy a bunch of expensive oils and other ingredients in case it didn’t turn out. The recipe I used called for lard and olive oil.) It was SO much fun!! I’m going to be making your recipe for the actual baby shower gifts once I get all the ingredients (now that I know I can do it!). Working with the lye wasn’t nearly as scary as I thought it would be. I just carried my water and lye outside separately, and mixed them very carefully. I’m so glad I found your site. I can’t wait to try your recipe. The soap I made in my test batch is great, but I think your recipe will be much more moisturizing and will smell even better! 🙂

  13. Emily Wells Avatar
    Emily Wells

    I’m so glad I found your site! I’m making homemade soap for the first time in about a week. I’m going to make your recipe, but I have a few questions!

    First of all, should I measure the water by weight or volume? Probably a dumb question since it would be impossible to measure out exactly 12.something-or-other ounces of water in a measuring cup, but I’m kind of terrified of lye, and I don’t want any weirdness happening, and I definitely want my soap to turn out!

    Secondly, I’d like to add lavender essential oil to this recipe. How many drops do you recommend? I’m planning on using your recipe exactly, not doubling it or anything.

    And finally, do you have any suggestions as far as tinting the soap? This is actually for baby shower favors, and her colors are sea foam, mint green and baby blue. I’m leaning toward the baby blue, but I’m not sure what to use to tint it. I’d like to go as natural as possible, but there are so many options–powders, liquids, spices, etc. What would you suggest? Thank you!! 🙂

  14. Stephen Avatar

    I used this recipe and directions to make soap for the first time. It was super easy and the soap works great! The only issue I had was once I was through cooking the mixture, it was difficult to spoon it into the molds, getting it to settle down into the molds. It was like trying to fill in a space with cool whip. Did I cook it too long (1 hr) or maybe did I get the mixture too thick when blending?


  15. Bai Avatar

    Hi Katie,

    Thanks for the lovely recipe.
    I love soap making and I read online that coconut oil in soap making should be kept below 30% as it will have a drying effect if use more than that. I am not sure how true is this. What is your experience with coconut oil in soap making?
    I recently made a batch of hot process soap, it feels little dry or waxy on my hand compared to cold process soap I made. Is this normal?

    Thanks. Have a great day!

  16. Mehvish Avatar

    Hi Katie, great recipe, I can’t wait to try it out! Just one question, if I wanted to add Shea butter, what percentage of that should I incorporate into the recipe? Thanks again in advance!

  17. Maria Ibanez Avatar
    Maria Ibanez

    Hello Katie,
    You have the best blog.
    Having said that, instead of following your instructions for either the hot or the cold process, I decided to go for a happy middle and ended up in a war zone.
    I don’t have a slow cooker, so once I poured the lye water into the oils, I kept stirring on the stove at a very low setting.
    The soap curdled!
    It was 500g of olive oil, 70g coconut, 70g castor, 50g jojoba… NOOOOOOOOOOOO!
    I went online ASAP and someone said to mix the oily part with some flour, but I have no flour at home!
    The closest thing I had to a powder soap ingredient was… diatomaceous earth. Otherwise I could have used hemp protein powder…? (I just thought of it).
    Anyways, I added 2 tsp and made a new batch with 100g olive oil to integrate it… but in the haste I added the earth to the oil, forgetting completely the lye… never mind
    I found myself with a pot of hard paste, similar to pumpkin paste, just slightly less orangey.
    I had to make a decision: Lose the batch or try to recover it.
    I decided to make another 500ml of olive oil soap and add the paste slowly until saturation, see what happened.
    I tried using a whisker, but it didn’t integrate, so I went for the stick blender; but I knew I would have to do it all at once instead of pouring small amounts because as soon as the blender started, the liquid would become solid.
    I had to work the paste for a long time with the stick blender and it was very tough to get it in a homogeneous state, but I MADE IT GO RIGHT!!!
    Or so I think.
    I have put it in molds and tomorrow I will check on it.
    Two questions:
    1. I’m afraid the saponification has not been as homogeneous as it should, and don’t know how safe it will be to use that soap on the skin.
    2. What will be the effects of the diatomaceous earth on the skin?
    Basically, do I gift-wrap it once dry and give it to my friends or my enemies?
    I will wait for your answer while the soap cures…
    Thanks for your amazing post.

    1. Katie - Wellness Mama Avatar

      What an adventure! I’d let it cure longer since it might not have fully cooked. Since the DE isn’t in powder state it should be completely safe on the skin as the only major risk is inhalation of the powder. It might actually be amazing for the skin 🙂 Let me know how it turns out and I’d love to share it if it turns out well!

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