How to Make Soap in a Crockpot using Hot Process Method

How to make soap in the crockpot using the hot process method
How to make soap in the crockpot using the hot process method | Source

Learn how to make soap easily using the hot process method. Soap making is a complex process, but certainly not difficult. Through this guide, I will show you step by step with illustrations, how to easily craft your own homemade soaps which you can later customize to meet your own needs.

First – A Bit of Soap making History

Did you know that the “soap” we buy in stores today is not actually soap at all, at least not in the traditional sense? Most products sold in stores are detergents and not soap. In the old days, soap was made by mixing animal fats with wood ash. The wood ash formed a sort of rudimentary type of lye. This soap was typically made without careful measurements and the end result was often lye-heavy soaps that would burn or irritate the skin. When done right, however, soap made in this fashion was not only wonderful for the skin, but very effective at cleaning laundry, pots and pans, and even for household cleaning.

Today, we can make wonderful soaps using old fashioned techniques but with modern equipment and safety gear. Once your lye (sodium hydroxide) is processed properly, it is no longer caustic and becomes glycerin. Today we can superfat and add more lovely skin healthy ingredients as well. Once you experience "real" soap - you'll never go back to store bought.

Personally; I've been making handmade soaps for several years and even had a sideline business for awhile. I enjoyed this very much, but unfortunately with work, school, and a family life got in the way and something had to give. Today, I still make soap for friends and family, and it's a wonderful, relaxing hobby. It has also been a great way for me to deal with sensitive skin. I can use homemade soaps and lotions without any of the drying, flaking, rashes and other issues I experience with most commercial products.

So, hopefully by now you are ready to try your hand at soap making.

Below are the detailed directions which I recommend you read all the way through at least once before trying your first batch. This will ensure you get the feel for the process and know what you are looking for as you prepare your soap.I will be using one of my own recipes for this tutorial which you are welcome to use, however you are also free to use any soap recipe of your choice.

We will be doing this via the hot process (HP) method, but you can use any cold process (CP) recipe you like as well. I will break down the method into several steps – preparation, safety, cooking stages, and pouring and molding.

Gathering soap making ingredients and equipment

Supplies and equipment for making soap.
Supplies and equipment for making soap. | Source

Step One: Gathering Your Supplies and Ingredients

Supplies Needed

  • A digital or postal scale to ensure accurate measurements – all primary ingredients are measured by weight not volume.

  • A heavy weight plastic pitcher and spoon for mixing your lye water solution. (never use metal)

  • An enamel or stainless steel pot or Crockpot for cooking – these should never again be used in the preparation of food and be devoted solely to soap making. Do NOT use aluminum! Use only enamel or stainless steel cookware.

  • Stick Blender (optional) allows for faster processing

  • A Mold – a large cardboard box lined with wax paper is great for beginners – no need to invest in expensive wooden molds just yet.

  • Safety Equipment: paper mask (only for when mixing the initial lye solution), gloves, eye protection, and a jug of white vinegar see step two for safety – it's important!

Ingredients Needed

  • Sodium Hydroxide (lye) must be 100% pure sodium hydroxide for our recipe you will need 12 oz.

  • Water 28 oz

  • Vegetable Shortening my recipe requires one full can of Crisco (48 oz) (or 100% vegetable based shortening)

  • Coconut Oil – 18 oz

  • Olive Oil, Soy Oil, Canola or combination for a total of 21 oz.

  • Shea Butter – 2 – 3 Tbsp

  • Essential Oil(s) or Fragrance Oil(s) – your choice – must be labeled safe for soap making

~Remember~ All ingredients will be measured by weight and not volume except fragrance or essential oils & superfatting oils.

You have to be careful with lye (Sodium Hydroxide). I use the Essential Depot brand and it's the best I've ever used. It is pure sodium hydroxide and not cut with anything that could be potentially dangerous.

IF you choose to purchase lye from a hardware store you MUST ensure it is 100% pure SH with no fillers or A) your soap may not turn out B) you may end up with soap that burns or irritates the skin.

Step Two: Safety Precautions – Very IMPORTANT

This actually gets its own section in our tutorial because it is extremely important. No matter how experienced you are with soap making, accidents can always happen. For this reason, it is very important to practice good safety measures each and every time you make soap.

Kids and pets should be removed from the area whenever you are making soap to reduce the likelihood of accidents or burns. Wearing gloves and goggles while mixing lye solution is extremely important because even a small drop can cause a very painful burn or damage surfaces. I highly recommend covering your work surfaces with a drop cloth.

Keep a jug of white vinegar handy because it neutralizes lye burns. Although your skin should be fully protected, we are human and if you should happen to get a drop on you the vinegar will stop the burn from progressing.

When you are mixing your lye solution you always add the lye to the water never the other way around– doing this backwards can have explosive results. Add your lye to your water and stir carefully until all lye crystals are fully dissolved. Mix your lye/water solution in a well-ventilated area and take care to not directly breathe the fumes. A paper mask can be worn during this stage to ensure you don't breathe the vapors. Mix your lye water ahead of time to allow it some time to cool before making your soap. Set it aside in a secure place.

Step 3: Preparing Your soap

Refer to the ingredients section above for my specific recipe – or you can follow your own recipe.

  • add your water to your pitcher (measured by weight!) and then slowly stir in your lye crystals. Stir until completely dissolved and set aside.

  • Add the container of Crisco to your pot or Crockpot (for this demo I am using a Crockpot) and begin to melt it over low heat

  • Next you will measure your coconut oil and add it to the Crisco

  • Next your other oils or combination of oils (olive, canola, soy) can be measured out and added. You can do this in whatever proportions you desire so long as the weight is correct.

  • Once all your solids are melted completely you can slowly and steadily stir your lye water solution into the oils – before you do this ensure all lye crystals have dissolved completely and that you are wearing your safety gear. Slowly pour while stirring constantly. Remember to wear your safety gear - gloves and goggles.

Your soap will go through several stages as it cooks and these are described and illustrated with pictures below.

Stage One: Trace

If you are cooking on the stove top (the Crockpot is easier in my opinion) you will need to keep your heat low and stir almost constantly to prevent your mixture from boiling over. With a Crockpot you don't have to stir quite as much, but regardless you need to be close and keep a careful eye.

The first stage, called Trace happens very quickly with hot process soapmaking, so quick in fact, I wasn't able to capture it on camera when taking the photos for this hub :). You will know this stage when the mixture is thick like a custard.

If you take your spoon and pull up a few drops and dribble it across the top of the mixture; it will sit on top for a second or two before going back down. This is trace and it may happen so fast that it appears to skip right over this stage and that's fine.

Stage 2 - Separation

Stage two is separation AKA yuck! what is this stuff!

The second stage your soap will go through is separation and curdling. During this phase, the soap gets kind of ugly and becomes a semi-gelatinous mess with white curd looking stuff and oil floating around it. If you don't know what you are looking at; you might start to panic, but hold tight because it will quickly pull itself together and start to smell heavenly as it saponifies further.

Separation Stage of Cooking Soap

look how ugly it is! - don't worry it's supposed to look like that for now :) it will pretty up - keep cooking!
look how ugly it is! - don't worry it's supposed to look like that for now :) it will pretty up - keep cooking! | Source

Stage 3 Champagne Bubbles

Champagne bubbles indicate that saponification is taking place.

The larger bubbles have mostly disappeared, and the mixture looks golden and uniform. Many tiny little bubbles will appear at the surface; making it look like champagne. At this point; you can turn the heat down lower and stop stirring a bit and you'll notice your soap starts to grow – this is where saponification1 really gets under way. Continue to cook and stir as needed until the water around the edges cooks off.

At the end of this stage, immediately before you reach the pouring stage, you add your fragrances and superfatting oils (Shea butter) for our recipe and stir it through. Doing this last prevents the fragrance from burning off due to high heat. The amount of fragrance will vary by what you use. For this recipe a half ounce to one ounce is usually sufficient. If you want stronger smelling soaps you may need to increase this a bit, but don't overdo it as you may seize up your soap. It would be a shame to come this far and ruin the batch.

At this point; you can also stir in some finely ground oatmeal, coffee grounds or herbal powders as well. This is completely optional, but can greatly enhance the quality of your soaps. Coffee makes nice dark brown flecks and is a natural deodorizing agent. Oatmeal is wonderful for dry, itchy skin. You can be as creative as you like and there are many recipes floating around. (For the batch in this tutorial I added coffee grounds which you will see turned it very dark for the pouring stage - it dries a nice medium tan color with brown flecks)

Champagne Bubbles / Saponification

see all the little bubbles in the oil on top? This makes your soap look a lot like champagne.
see all the little bubbles in the oil on top? This makes your soap look a lot like champagne. | Source


see it try to grow out of the pot? At this point saponification is happening quickly - and soon it will be time for the final stage - the pour :)
see it try to grow out of the pot? At this point saponification is happening quickly - and soon it will be time for the final stage - the pour :) | Source

1.Saponification: A really big word that means your lye and fats are having a chemical reaction that turns the sodium hydroxide (lye) into glycerin. It is this process that allows the oils and water to mix and form a solid – soap :).

What Soap Looks like When You "pour" It into Your Mold...

As you can see the consistency of "pourable" soap is more like lumpy heavy mashed potatoes.  You will want to spoon it in very quickly and press it down as you go - it's HOT so use wax paper and something sturdy (I use a piece of board) to press it.
As you can see the consistency of "pourable" soap is more like lumpy heavy mashed potatoes. You will want to spoon it in very quickly and press it down as you go - it's HOT so use wax paper and something sturdy (I use a piece of board) to press it. | Source

Stage 4: Pouring and Molding

The final stage is the “pouring” stage. I use quotes here, because this is actually a bit misleading. Soap that is ready to mold will not actually pour at all and has to be spooned into the mold. At this point, your soap should be moist looking but not wet. The water should be cooked off from around the edges and have the appearance of very lumpy mashed potatoes. This means you are ready to put the soap into your prepared mold.

Once your soap is at the pouring stage; you need to move quickly. If possible. you may want a second pair of hands to help you. Quickly scoop your soap into your mold, pushing it down firmly and evenly. I do this by placing wax or parchment paper on the top and using a flat board to push it down and remove the air bubbles. Once I have done that I pick the mold up and drop it a couple of times to ensure it is air pocket free. If you don't wish to drop it on your table; you can also tap the mold around the edges with a spoon to remove air bubbles as well.

You will find that if you wait too long to pour, or move to slow, your soap my start to dry out and it will not want to stick to itself. If this happens, put it back in your pot or Crockpot on low heat and add a tbsp or so of oil and mix it through. Even soap that is dry and doesn't mold well will still be useable, so don't worry.

Your soap should stay in the mold until it is hardened all the way through. This time will vary based on the size of your recipe and mold, typically this will be several hours or overnight. Once the soap is hardened and cooled, remove it from your mold and cut into bars. Allow your bars to cure for at least a few days for best results.

To test your soap to make sure it is fully cured; touch a corner of the bar to your tongue. If you feel a tingle at all this means it is still curing and is not ready for use. If not, feel free to start using and enjoying your soap.

Lovely Bars of Handmade Soap

lovely bars of homemade soap - anyone can do this.  It's complex but not hard.
lovely bars of homemade soap - anyone can do this. It's complex but not hard. | Source

What is Your Favorite Way to Make Soap?

  • I do melt and pour - it's very simple and I don't have to mix lye
  • I prefer cold process because I am confident and patient :)
  • I love hot process because it is done faster and I can see what I'm getting quickly
  • I have never made soap but I'd love to give it a whirl!
  • I have used Soap Berries or Soap Nuts to make natural detergents
See results without voting

© 2012 Christin Sander

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Comments 44 comments

ChristinS profile image

ChristinS 11 months ago from Midwest Author

Good luck with batch number 2 Marti :) It's a little bit of a learning curve, but you'll get the next one fine I'm sure!

Marti 11 months ago

This was very helpful. I actually attempted my first batch yesterday and felt it was a flop. However, had I read your article FIRST, I would have known that my soap was just like it needed to be. Thanks so much, I'm ready to try it again. (I scrapped the first batch, It's in a loaf pan sitting in my laundry room)

ChristinS profile image

ChristinS 13 months ago from Midwest Author

Betty, I have no idea why your soap would dry out in only 15 minutes. Can you share what you did? It sounds like you had your heat too high or that you got your measurements wrong, or possibly both. (Did you measure by weight and not volume?)

Betty 13 months ago

soap dried out in crock pot only after 15 min after rising to the top can it be used?

ChristinS profile image

ChristinS 16 months ago from Midwest Author

You're welcome Noemi enjoy :)

Noemi 16 months ago

thank you for this recipe

ChristinS profile image

ChristinS 18 months ago from Midwest Author

Thanks for the read and comment Besarien. I don't actually sell soap anymore but I used to. I am currently so busy doing multiple projects that something had to give - and well, that was it lol. I do have a lot of hubs on soap making though and if you ever have any questions feel free to ask :)

Besarien profile image

Besarien 18 months ago

Hey Christin! Really enjoyed this hub. I did make soap once via cold process which turned out nice though I didn't use enough essential oil to give it much of a scent. I have never cooked it. A crockpot sounds ideal. This is definitely on my to do list. Do you have a website where you sell your soap?

ChristinS profile image

ChristinS 21 months ago from Midwest Author

You're welcome Holly, so glad you are enjoying the hot process. I was the opposite actually. My mom taught me cold process soap making, but then I would spend all that time anxiously waiting to know if the soap was good etc. and I thought you know, there has to be an easier way :) so I started experimenting with hot process techniques. Crockpot is by far easier and the cleanup is a snap for sure. Thanks for reading and commenting!

Holly 21 months ago

Have been making CP soap since 1996. Decided to try HP soap the other night and have made 3 batches since. I can only do 1/2 of what I usually do, it takes a bit longer but you save on the cleanup! Don't know why I never tried it before? Only tried it because my sales are way up and my supply is way down and I have lots of orders to fill in the next month. I can bypass the 6 weeks to let it cure. Think I will be switching over. Thank you for your tutorial!

ChristinS profile image

ChristinS 23 months ago from Midwest Author

Dee is correct in that wrong measurements can make a mess and you don't want too much lye. Use the recipe as written in my hub it works very well and I've used this same recipe for years.

Dee Huffman 23 months ago

Lynda making soap is an art like baking a cake. The difference is that the lye not fully processing could burn someone very badly.

You could half the recipe and put it in a soap calculator to get the proper amount of water and lye. But if the oils aren't right you may get a mess. Or you may get lucky and get a great batch of soap.

So it's best to start with a recipe that works. (Always use a soap calculator is one. ) Use it even when the recipe tells you how much to use. Read up on soap making. Elevation can change your recipe.

Be careful and you may fall in love with soap making too!


ChristinS profile image

ChristinS 23 months ago from Midwest Author

Hi Lynda

I would do the recipe as is the first time. Recipes for soap are very precise and go by weight. I haven't made a half batch before, so I wouldn't recommend it. As for lye, you need to purchase it either online or from a hardware store, but you must be sure that it is ONLY 100% pure sodium hydroxide. You find it in the plumbing aisle. I would highly recommend you purchase the brand I mentioned in my hub or go on Amazon and search for sodium hydroxide. Because it is a caustic substance often used for illegal purposes, you may be questioned when buying in bulk what your intended purpose is. I was when I went to the hardware store lol - they were fine when I told them I was making soap. I prefer ordering online - the quality is higher and it is actually less expensive even with the higher shipping. Good luck :)

Lynda 23 months ago

Very informative tutorial on the hot process of soapmaking. I have wanted to make soap for years but it seemed to intiminating. Your crockpot method & easy to follow directions have me thinking I can do it. My only question is if will work if I half the recipe & make a half batch for my first time? Also, can lye be bought at any pharmacy? Thank you for your excellent tutorial!

ChristinS profile image

ChristinS 2 years ago from Midwest Author

Thanks a lot VVanNess hope you try it and enjoy it :).

VVanNess profile image

VVanNess 2 years ago from Prescott Valley

Very nice. I've have wanted to start making my own soaps for a while now. And you have made it look super easy! Thank you!

ChristinS profile image

ChristinS 2 years ago from Midwest Author

RTalloni it's really not difficult to do :) hope you'll give it a go

RTalloni profile image

RTalloni 2 years ago from the short journey

Interesting to learn about this method. I may yet muster the courage to give it a try! Thanks for a good look at the details.

ChristinS profile image

ChristinS 2 years ago from Midwest Author

Hi mama - so glad you are encouraged to try your own :) For this recipe I am using one of the very large oval crockpots, but you can use any size hot processed soap recipes (they are all over the internet) and a smaller pot if that is what you have. I like the larger crockpots because you can make large or smaller batches. Yard sales and thrift stores are good places to find one since you'll only want to use it for soap after that.

Mama Chica 2 years ago

I love this! I enjoyed the bit of history, the recipe, pictures, and descriptive instructions for making the soap. I'm truly inspired to make my own. :) On that note, what size crockpot is that you're using?

ChristinS profile image

ChristinS 2 years ago from Midwest Author

No, it's never a good idea to change a soap recipe. You can't just half a soap recipe like you can food recipes, everything relies on certain proportions to come together properly. I would look online for a smaller recipe :)

Rachael 2 years ago

Hi! Great article! I have a small crockpot, maybe half the size of the one you show in the photos. Should I cut the recipe in half?

ChristinS profile image

ChristinS 3 years ago from Midwest Author

I don't get soap rings with my soaps, but I also steam clean my shower/tub weekly with a steam wand because we have hard water which also can build up if you don't stay on top of it. I suppose it would depend on the ingredients you use, but I don't see why it should leave a ring. Thanks for reading and commenting

Kay 3 years ago

I love the idea of making my own soap and have considered doing so but haven't tried it yet. Your article has inspired me once again and I am going to try it. However, I have a question about the homemade soap. Does it tend to leave that icky soap ring in the bathtub or shower? I really hate that.

ChristinS profile image

ChristinS 4 years ago from Midwest Author

awesome, be sure to post and let me know how it goes. Enjoy!

mrshorsefly 4 years ago

I have all the supplies lined up and ready to go...this recipe is going to be my very 1st attempt at making my families own soap supply!! After reading endless websites and watching Youtube I am sure I will have NO problems! Your article actually inspired me to give it a "go"!! Thank you very much!

ChristinS profile image

ChristinS 4 years ago from Midwest Author

Thanks Rachel for the comment and votes. Of all the methods I've tried, I love the crockpot one the most. It is the easiest to control and if life gets in the way and you have to walk off for a few minutes here and there you can do so knowing it isn't going to ruin your batch etc. I hope you'll enjoy the crockpot method too :)

Farmer Rachel profile image

Farmer Rachel 4 years ago from Minnesota

This is an awesome tutorial! I've been cooking my soaps in the oven - maybe I'll have to try the crockpot. Looks a little simpler. Your safety precautions about the lye are spot-on, too. Great hub! Voted up etc :)

ChristinS profile image

ChristinS 4 years ago from Midwest Author

thanks for commenting unknown spy - let me know if you try the hot process method sometime and how you like it. I like this much better than the cold process because you can use it faster :) and you'll know immediately if it's going to turn out or not.

unknown spy profile image

unknown spy 4 years ago from Neverland - where children never grow up.

veeryyy creative! we did this one time as a research but guess, this process is definitely great than ours :)

ChristinS profile image

ChristinS 4 years ago from Midwest Author

creatively yes, hot process soap is different than cold process. With cold process you absolutely must cure it that long. With hot process the cooking does most of the saponification so you don't need to cure it very long at all.

creativelycc profile image

creativelycc 4 years ago from Maine

This is great, I can't wait to try this recipe. I recently started making soap. One thing I'd like to ask though. My recipe said to cure the soap for 6 - 8 weeks and your is for a few days. Does cooking the soap make the difference?

ChristinS profile image

ChristinS 4 years ago from Midwest Author

thanks Shawn glad you enjoyed the hub and hope you will have a blast making soap - it really is a fun hobby. :)

Shawn May Scott profile image

Shawn May Scott 4 years ago

Wow!!! I am going to try this this summer. I have always want to make home made soap. Voted up, useful, shared and followed. Thank you for sharing this recipe.

ChristinS profile image

ChristinS 4 years ago from Midwest Author

Hi Dee - lotion is very easy actually! and SO much nicer on the skin than any commercial products. I plan to do a hub on how to make it. If you want to keep it for any length of time or don't want to refrigerate it you will have to add some preservative, but if you don't want to do that just add some vitamin E and a bit of grapefruit seed extract and refrigerate it in small batches so you can use it within a month or so. I plan to do a lotion making hub soon too! :)

SEXYLADYDEE profile image

SEXYLADYDEE 4 years ago from Upstate NY

Great hub. I too am a soapmaker and try to make as much as I can. Once you learn how to properly handle the lye the fear of it goes away. Respect for it never does. Loved the history of the process. I have lupus and my skin is very sensitive. It got me started making it. I just bought a lotion making kit to get an idea of how it's done. Sounds like I should enjoy that too. Thanks. Dee

ChristinS profile image

ChristinS 4 years ago from Midwest Author

Hi Danette,

Thanks for commenting. It really is a fun hobby and my skin definitely does a lot better with it in the winter months. I also tend to make handmade heavier creams for winter too - the dry air is so hard on the skin. Lotion is even easier than soap - I'm going to try to get a hub going for that too before school starts back up :)

Danette Watt profile image

Danette Watt 4 years ago from Illinois

Interesting bit of history about soap making. I'm not surprised that today's soaps are very drying (for our skin). I experience that in the winter quite a bit. It looks like a rewarding craft.

ChristinS profile image

ChristinS 4 years ago from Midwest Author

Hi Tebo - homemade soaps are wonderful for sensitive skin. A lot of people are scared off by sodium hydroxide (lye) that goes into making "real" soap - however this goes through a transition and is converted into glycerin leaving behind nothing but wonderful things for your skin. The only time you might have true synthetics in homemade soaps are if you use "fragrance oils" instead of 100% pure essential oils. If you have sensitive skin you may want to omit fragrance all together and stick to additives like oatmeal (which helps soothe sensitivity)

Thanks for reading :) hoping you'll give homemade soap a try :)

tebo profile image

tebo 4 years ago from New Zealand

Homemade soap sounds great. I am continually looking for more natural cleaning products and this looks interesting. As you have mentioned it is better for people with sensitive skin, so must be a better option and at least you know what you are putting in.

ChristinS profile image

ChristinS 4 years ago from Midwest Author

Hi Arlene - thanks for the comment. Old fashioned lye soap tended to be made with Tallow which can go rancid and has quite a yucky smell. If you stick with all vegetable as I do with my soaps you'll find that doesn't happen. Also, these days we add essential oils and fragrance that our moms and grandmas didn't - so you can make your soap smell as great as you want :). If you use the right essential oils you can also make it therapeutic :)

Pamela - Lavender soaps are lovely and were always one of my best sellers. I make them still for family and friends. Nothing relaxes quite like the scent of genuine lavender essential oil. I often put it in my oatmeal soaps as well - very soothing body, mind and soul :) Thanks for reading and commenting

Nick - yes I want to make it more often again - imagine that :) too bad we can't keep up with that and going to school etc.

NicholasA profile image

NicholasA 4 years ago from Midwest

I love it when you make soap. The whole kitchen smells wonderful. Great Hub :-)

Pamela N Red profile image

Pamela N Red 4 years ago from Oklahoma

I used to make homemade soap a lot but got out of the habit. I've recently thought about making lavender soap. Great article.

Arlene V. Poma 4 years ago

That first photograph looks like caramel! Very nicely written, and I may be tempted to try. My mama used to make soap, but it involved lye. It didn't smell all that great, either. Voted up and everything else. Bookmarked, too.

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    Christin Sander (ChristinS)1,262 Followers
    114 Articles

    Christin is a soaping addict who has made and sold soaps and other natural beauty products for over 10 years.

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