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
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!
I made this soap last night! It came out beautiful for my first soap, I added an oz of cocoa butter at the end of the cooking process as it started to cool, and I used maple pancake scent with a little powdered baking chocolate swirled in. I wish I could eat this soap, it smelled so nice and lathered nicely. I didn’t expect it to lather, because all the homemade soap that I have ever purchased did not lather well. Thank you for your recipe!
Hi there!
I’m wondering if you have re-used this recipe as a base for future “melt and pour” projects? Can it be melted down and re-molded with additives such as essential oils?
How many molds would I need for This batch
Thanks for the information on soap making. You mentioned you buy everything needed in bulk? Would you please share your contacts for bulk buying?
I apologize if I simply missed it.
Hi there,
Do you have to use a metal spoon when mixing the lye to water? Or is a wooden spoon ok?
thanks,
Sarah
Thank you for this awesome post on soap making! I make my own laundry detergent, fabric softer, and dishwasher tablets but I haven’t been brave enough to try soap making yet because of the lye. I read a bunch of your posts about soap making and now I am less nervous and super excited to try it out! I probably missed it, but did you post a link to where you got your huge tub of tallow?
at what point do you add things like coconut milk, bentonite clay, sea salt? at the same time as the essential oils?
Followed step 9. Step 10. Is this supposed to be light and airy….I set my timer to 15 minutes but at 10 minutes it was bubbling over. I stirred in my eo and spooned into my molds. Covered with parchment. Fingers crossed we’re good.
I couldn’t find how many bars of soap you can make out of this recipe. I understand it depends on the size of the molds, but since I’ve never made soap like this before and I need to get molds, I’m curious how many medium bars of soap, like 3X2 and a half inch thick, this might make. It doesn’t have to be perfect, but close would be helpful! Thank you!
Thank you for the recipe. I am going to make my first batch later this month. I am wanting to make a lemongrass and spearmint soap, however, I don’t know how much essential oils I should use. Do you have any recommendations?
I used almond milk instead of water and put a spoon full of honey in it but I think I cooked it to much. It was a lovely colour but 15 minutes later it was really dark. Was that because I used the almond milk instead of the water? The lye and almond milk didn’t go dark when I put them together it was only in the last 15 minutes of cooking everything
You want to use 100% sodium hydroxide (lye) crystals. Big box stores usually don’t sell lye, but you can usually find it at a locally owned hardware store or purchase it online through Amazon. Just make sure it’s 100% sodium hydroxide crystals.
Just FYI to everyone —
With 50% coconut oil, this soap may make your skin VERY DRY due to the high cleansing properties of coconut oil. The recommended range for cleaning values in soap is 12-22, and this recipe produces soap with a cleansing value of 34. I would not recommend this soap recipe for any who struggles with dry or sensitive skin.
A more balanced recipe would be:
– 21 oz. Olive Oil
– 11 oz. Coconut Oil
– Same amount of water and lye as in original recipe.
Several people have asked about what type of mold to use. The recipe Wellness Mama provided in the tutorial and the recipe I provided above would produce about 3 pounds or 49 ounces of soap.
I just learned about this cite and i’m interested in soap making. Thanks
Hi all,
Very excited to try soap making. Question about soap molds, I will be using the basic bar mold. How many molds do I need to order for this recipe.
Thank you
How much soap does this recipe produce?
Hello,
How are you able to have perfectly looking and smooth (flat) flower soaps using Hot Process? Usually HP soaps look lumpy and rustic.
Great post Katie, thanks!
Another good source for lye is a local grocery store. After SEARCHING for lye all over the largest nearby city, I stumbled across it a my small town local grocery store. Look in the drain cleaner section. Make sure it says 100% lye though.
I’ve taken a couple of years off from soap making but I’m ready to get back into it over the holidays, specifically a shampoo bar.
Hi,
Thank you for this recipe! While the soap is cooking in the crockpot, do you continue to stir it, or just let it sit?
I usually just let it sit, but stir it occasionally if it looks uneven.