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
The 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.
Gathering Equipment
I 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:
- A slow-cooker (I got an older one at a thrift store)
- A digital scale (this is important for making a soap that is not too harsh or too oily)
- Glass jars and bowls
- A stick blender
- plastic cups (optional)
- A metal spoon
- A wooden spoon
- A spatula
- Soap molds (or an old cardboard box lined with parchment paper). I have green flower molds, red silicon rose molds and basic bar soap molds.
- Gloves and sunglasses or eyewear
- A large bottle of white vinegar for neutralizing the lye mixture if it spills on anything.
Slow Cooker Soap Recipe
Materials
- 16 oz coconut oil
- 16 oz olive oil
- 4.844 oz lye
- 12.16 oz water
- 1 oz essential oils (optional)
Instructions
- 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.
Notes
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!
Homemade Natural Body Wash
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I wish I was patient and/or precise enough to attempt my own homemade soap making. I buy handmade soaps, instead of the store-bought variety, but I simply don’t think I could manage this kind of project. I’m thankful that people like you do, though, because that means I can enjoy additive-free soaps, too!
I love HP soaping.. I’m the most impatient person! And I’m none too precise.. You only need to be precise to the gram, ml or ounce, don’t stress about it.. Just do it! Heaps of addictive skin friendly fun, however I would substitute some of the coconut oil in this recipe for sustainable palm or rice bran ( vitamin e helps with preserving it and good for skin) or macadamia( close to mans skins ph non comodogenic ) great post! Thanks.
I make soap all the time, everyday!! You can use almost any oils, but some work better than others. Olive oil and coconut oil are staples in most recipes. Lame, store bought “soap” really can’t compare to the real thing. The store-bought version has all the natural glycerin removed! Your skin will feel amazing and you will almost never need to use lotion if you regularly use good handmade soap! I make and sell all natural handmade soaps!
Do you have an online store?
I make handcrafted skincare products including soap. I will also add to be sure you use protective equipment. Safety first! Don’t be afraid of the lye, just respect it., Also, always add lye to your liquid. NEVER add water to lye or you wiil see a big volcanic explosion!
I love that you take the extra step to put them in cute little molds. It makes it fun!
Thank you Katie ! i lovelovelove to make soap !!! It’s totally addictive once you get started.
1 of my favorites is fresh ginger , orange and frankincence…allof them healing in their own right. I love the hot process because the scent sticks MUCH longer when you add it at the very end. and there are so many natural colorants…indigo, activated charcoal, woad, rose, green and blue clays…ogosh, lovely,
laur
Lately, I’ve been feeling like soap is too harsh for my skin because of the lye and I’ve stopped using soap at all when I shower. However, I miss the suds and the smell. Do you think there is any harm to your skin by using soap?
Not if it is properly made
What do you think of probiotic soap and the effect of regular soap on your skins bacterial colonies?
I have a post on this soon, but I think it is an important consideration
Soap works on germs/viruses by making them slippery and easy to rinse away. So adding probiotics doesn’t really make sense–you’ll rinse them away, too. But maybe you could put probiotics in hand lotion? If you kept it refrigerated?
Soap works on germs/viruses by making them slippery and easy to rinse away. So adding probiotics doesn’t really make sense–you’ll rinse them away, too. But maybe you could put probiotics in hand lotion? If you kept it refrigerated?
Maybe you need a higher superfatted soap. This way it helps create a milder soap. Also, are you using handmade soap or store brought soap. If using handmade soap, you also want to make sure the soap has been fully cured since cured soap produces a milder soap.
If the soap is made correctly there should not be any lye left in the finished soap to cause dryness or irritation. Homemade “lye” soap (as some call it) is known for being gentle. Super fatting leaves excess oils that help to moisturize and homemade soap retains all it’s natural glycerine (which is removed from most conventional soap or detergent bars) that is good for the skin as well.
The types of oils used in the soap can have a different impact on your skin. (hi coconut oil, more than 30%, can be drying… But a higher super fat, higher than normally recommended, can help to combat that) People with sensitive skin tend to prefer high percentage of olive oil, as well as soaps made with things like goats milk.
I made this soap adapting my Uncles old recipe using rendered bacon oil (we raise pigs) and have never found it drying. What is “super fatting”?
Buy pH paper and press it against soap surface. If pH paper turned blue from original yellow colour then you have added lye more. If it is dark red it is too acidic. pH is used to monitor saponification. Very high pH would burn or irritate your skin. Dove soap has acidic pH.
I’ve never made homemade soap before. I’ve always wanted to since I have very sensitive skin and have to watch the types of soaps I use. The lye has always made me second guess making it myself. This recipe sounds really simple and I would like to try it though. I’m pregnant now, so just to be on the safe side I’ll wait until after this baby’s born. 🙂 I’ve pinned the recipe for later reference. Thanks for sharing. 🙂
I have been wanting to make my own soap for a long time. My worry is that I’m such a klutz and I’m afraid I’d spill the lye on myself or get hurt with it. I know it’s safe once it’s made, it’s the interim I’m concerned with. Any other recipes that are safer when it comes to the raw product?
Most soap recipes use Lye in some form. Could you have someone help with the lye mixing part if you are worried about it?
You can’t make handmade soap without lye, unfortunately. It has to undergo saponification, from the lye with oils in order to have an end result of soap. You can do melt and pour which already has lye mixed into it but most melt and pours are still chemically laden and this takes away from it being handmade. Soaping is not recommended when pregnant.
I am pregnant with my 8th baby and I make lots of soap. Many do while pregnant. I’ve made soap during several pregnancies and even taught soap making workshops the last 2 times I was pregnant.
You just need to be aware of the fumes from the lye (I will mix outside and be careful to not breathe in fumes, or have dh mix it for me) as well as the effects of any essential oils used for scenting that may be contraindicated while pregnant.
This is what finally got me comfortable in using *LYE*. it works like a charm, as it is where it was meant to be used, next to soap making anyway 😉 Basically, i like to cold soap with goats milk (which reduces the fumes!) so, i put a glass bowl IN the sink (this way, IF lye should spill out, its in THE BEST possible place, instead of my counter or floor right? YES!) with ice and a little water. Then I sit my smaller glass bowl in the ice water. I add my pre-measured goats milk frozen bars and pre-measured lye, spoonful by ever so slow spoonfull, sirring a LOT in between adding each spoonful (because i want to make sure the lye is dissolved as much as possible before adding more or it could make lye chunks that dont want to dissolve very easy). I Sit my cup of lye granules, beads or flakes right in the sink next to the bowls so if i bump it or something happens, i can push it down the disposal and rinse it away, slowly of course so it doesn’t erupt like a volcano. Then while the lye mix is dissolving i get my oils together and melted and to the temperature im looking for then sit it on the counter next to the sink where the lye is. My stick blender is plugged in ready and i slowly pour the lye mix into the oils and slowly carefully on low blend in the lye mix! never pull the stick blender out while its running! Once it comes to trace you can add your colors or scents and spoon it into your molds! My basic point here is to keep your lye solution in the sink while mixing it up. Dont stand directly over it while mixing because the ammonia type smell of the fumes will not smell nice but not harmful either really. just dont stand directly over it.
As a long-time soapmaker, I would like to share that everyone making soap with lye (whether hot or cold process) I recommend you wear long sleeves, eye protection and gloves (as she described above) while making soap. Also, lots and LOTS of ventilation when you’re mixing the lye water. The fumes will dissipate in a few minutes, but are highly irritating at first.
If you are very cautious, move slowly, and remember the #1 Rule (Add the Lye to the Water, not Water to the Lye!) you will be fine. Done properly it’s no more dangerous than cooking with boiling water. And diligent cleanup is a must. Lye crystals can *jump* and scatter due to static – especially in the winter and when pouring them out of the typical plastic jar. Just dampen a dishcloth with cool water and a splash of vinegar and wipe down your work surfaces.
I Have been making crockpot soap for over 20 years … the beauty of this method is that you can use it immediately rather than having to wait the 6-8 weeks cold process soap takes. Of course the longer crockpot soap cures, the harder the bar! I am allergic to all commercial bath & body products … that is until I became a Young Living Member … their bar soaps are just like one of my favorite soap recipes and their body wash, shampoo, foaming soap & facial cleansers contain no harsh chemicals especially parabens which destroy my skin.
melt n pour glycerin , you can get it at any craft store. Super easy fun way to “make” your own soap.
Can you explain more? No lye?
Using ice cold water to dissolve the lye might be a good idea.
Katie, first of all thank you for making this so approachable. Second, if pouring into a large mold, when is it appropriate to cut the bars apart?
After about 12-18 hours they can be popped out of the mold and cut.
Question- can I add a tint to this recipe? And when would be a good time to add it? With the scent? Or earlier?
I’ve been making soap for just over a year. If I want to add tint, I get natural powders that give colour. Add the powders to the oils and blend in very well. Then add the lye and follow the remainder of the recipe.
When I am making hot process soap, and I’d like more than one color, I do it after the soap is cooked. Otherwise, you cannot swirl, or add multiple colors. I use natural colorants also, and since you can superfat at the end, you can mix them in a little bit of olive oil before mixing them into the finished soap.
You can separate HP soap into different containers, or do a HP in the crock swirl.
Hey Katie,
Thanks for the great soap recipe! I tried this out a few days ago, and by the time i got it into the molds it was like crumbly wax. Do you think i cooked it too long or do you know what may have happened? I was thinking of just melting it down to make liquid soap, but not sure the soap turned out right or if it would be safe to use.
I had this same problem.
I spooned the soap into molds. The next day it was a bit crumbly and the mold designs didn’t take well.
I tried throwing it all back in the pot with some water, but a few days going they are still soft and wet (I lifted one up). I think now I still have to wait longer. I probably added too much water in my attempt to fix the crumble and lost mold designs.
I used a silicone mold like the one you showed in the video, instead of waiting overnight I popped the soap in the fridge for two hours, took it out and cut it, it was perfect! Thanks for this recipe Katie, I followed it as written and my first attempt at soap making is a success! YAY!
Will this soap disinfect germs on your hands? I know they say to wash you hands with soap and water to stop cold viruses or germs from spreading in your home but this is just oil so will it work? Thanks!
Studies show that regular ol soap and water does clean as well as ones with added (usually toxic) antimicrobials. Google it. The key point being that you actually have to wash your hands for a full minute, not just put soap on then rinse. If you wanted to make a more antibacterial soap you could use some essential oils which would add an extra bonus of a pleasant scent.
As a nurse, we learn that the friction, when washing your hands, is most important & cleaning under your fingernails each time you “scrub” your hands (to ensure you’re not harboring any germs or bacteria that can cause some pretty nasty health issues, such as EColi).
My mom & I have been making our own soap & laundry soap for years. Love it! Don’t use anything else.
I work in the medical field and have never heard to wash for 1 minute (unless prepping for surgery). 30-40 seconds is plenty long enough to wash your hands.
I work in the food industry and was taught to wash hands for at least 20 seconds. Also, because soap is slithered, it does a great job getting rid of germs, etc. Overuse of antibacterial soap creates super germs.
Yep, handmade soap is meant to cleanse, cleanse away dirt.
All soap is “antibacterial” if you scrub your hands properly. Sing “Happy Birthday” twice while you’re washing.
And this soap recipe is awesome. I used slightly more coconut oil and olive oil to “superfat” my soap, which makes it nice and moisturizing.
I’m new to this! My daughter and I are looking into making soap for teacher gifts this Christmas. How much more Olive Oil and Coconut Oil did you use?
Thanks for the question. Also interested in answer.
How much essential oil do you use for this recipie? Do you really use 1 whole ounce that seems like a lot.
She tells how much she used in the article….