This is really long...but it might be helpful to somebody.
Ever since I started making soap I wanted to make liquid soap. I’ve done it more than once but didn’t really understand the concept behind it so I made many mistakes. If you’ve tried looking for liquid soap help on the web you’ve probably noticed how confusing the information is out there or simply the lack of information available.
If you really want to get serious about liquid soap making, make your own recipes and really understand the chemistry then get Catherine Failor’s book Liquid Soap Making. It will make your liquid soap making life so much easier
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Here is my method, process and understanding…hopefully I can help someone out who is confused like I was. I assume you know the basics of soap making. Be sure to wear proper safety gear and take all safety precautions when working with potassium hydroxide.
Oil choices play a MAJOR role in liquid soap making if you want to achieve a clear soap. You want to stay away from oils that are high in stearic, oils that contain high amounts of un-saponifiables and other “cloud” causing components.
My choice liquid soap making oils are generally:
Coconut oil
Olive oil
Castor oil – is also a solvent so can help with the clarity of your liquid soap
Safflower
Sunflower
Palm Kernel oil
Hemp – use in small amounts
Jojoba oil – used in small amounts because it does contain un-saponifiables which can cloud soap
To compare, here are some popular brand examples:
Dr. Bronner’s Peppermint Liquid Soap ingredients are:
Water, Organic Coconut Oil, Potassium Hydroxide, Organic Olive Oil, Mentha Arvensis, Organic Hemp Oil, Organic Jojoba Oil, Organic Peppermint Oil, Citric Acid, Tocopherol
Whole Foods Market Organic Castile Soap Peppermint ingredients are:
Organic pyrus malus (apple) juice, saponified oils (organic cocos nucifera [coconut] oil, potassium hydroxide, organic helianthus annuus [sunflower] seed oil, organic sesamum indicum [sesame] oil, organic simmondsia chinensis [jojoba] seed oil), aqua (purified water), organic cyamopsis tetragonoloba (guar) gum, organic mentha piperita (peppermint) oil, organic aloe barbadensis (aloe) leaf juice.
I generally stay away from:
Palm - although if used in small amounts can add “body”
Avocado – high un-saponifiables
Lard/Tallow – like palm, if used in small amounts can add “body”
Shea/Cocoa butter
Now…if you don’t care about clear liquid soap, then simply use whatever oils you want. You’ll just have to experiment.
The “Failor” method of liquid soap making is to calculate your recipe with about a 10% excess of potassium hydroxide. This is to ensure that all of the oils/fats have been saponified and there are none left over to “cloud” the soap. Potassium hydroxide contains varying amounts of water. I’ve read typically between 10-15%. The diluted soap is then neutralized with boric acid, citric acid or borax. Some people make there soap with a 2% excess of potassium hydroxide and do NOT neutralize. To each their own...find out what works best for you.
Here we will use the “Failor” method of using a 10% excess of potassium hydroxide and then neutralizing.
So here is my main liquid soap recipe that is tried and true that gives me a great bubbly lather. It does seem a bit high on coconut oil, but the olive and jojoba tone it down as well as our superfat ingredients, glycerin and Turkey red oil (sulfated castor oil).
35 oz coconut oil
10 oz olive oil
3 oz jojoba
39 oz water
13 oz potassium hydroxide
2 oz potassium carbonate (optional)*
Superfat (optional)
Vegetable glycerin – 1 ounce per pound of diluted soap
Turkey red oil – 1 tsp per pound of diluted soap**
**Turkey red oil (sulfated castor oil) is water soluble and makes a great superfatting agent for liquid soap. It does not cloud the final product and also acts as an emulsifier.
*Potassium carbonate makes liquid soap much easier to stir. You don’t need it to make a successful batch of soap. Please note that it does need to be neutralized per Failor. I’ve found it at a local supplier selling beer brewing/wine making supplies. You can also find it online.
Crockpot Method
I cook my liquid soap in a crock pot. You want to pick a crock pot with enough headroom to allow your soap to expand. I typically don’t fill mine any more than about 2/3 full but I tend to stay around 1/2 full. Weigh your crock pot. You will want to know how much soap paste you end up with after the cook. Yes you can add up your lye, water and oil amounts but some water evaporates during the cook and I like to know exactly how much paste I end up with.
Cooking the soap paste takes about 3 hours.
Turn your crock pot on high and add your oils. Heat until melted (or melt in microwave and add to crock pot).
Mix your lye solution by adding potassium hydroxide to your water. Once the potassium hydroxide has dissolved, add the potassium carbonate to the lye/water solution and mix until dissolved.
Add your lye solution to the crock pot. Blend until you reach trace.
Trace is different with liquid soap than with soap made with sodium hydroxide. It stays liquid for longer and then all of the sudden you end up with extremely thick trace. In my experience it also takes longer. So keep mixing. Even when you think you’ve reached trace, mix a bit more until it is quite thick like mashed potatoes. I have noticed when using potassium carbonate that trace is a bit thinner than when not using it.
I’ve set the soap to cook without getting a decent trace several times. I get a trace that looks similar to sodium hydroxide soap trace and I think I’m done. I’m not, I should have kept going. What usually happens is the mixture separates and can even rise up out of the pot. If this happens just take your stick blender and mix some more until you get trace; it will be quit thick.
After you have reached trace you can put the lid on your crock pot and let cook. I typically leave mine on high, but others turn theirs down to low. On high mine keeps the soap at about 180. I believe Failor says to cook soap between 180 and 200 but I’m not sure if this is set in stone or just her personal experience.
During the first 30 minutes keep a close eye on your soap. This is the time frame that it will usually separate (if you did not mix to a good trace) or it will mushroom up. If it separates, mix to trace…if it mushrooms up, stir with a spoon to release air and it will go back down.
I typically stir my soap paste every 30-40 minutes. It will be pretty thick so you don’t actually stir…your more or less glop, moosh and fold it.
Once it has been cooking for 2 1/2 hours I test. Heat up about an ounce of water and dissolve about 1/2 ounce of soap paste. If it is clear it is done (no unsaponified oil is left making it cloudy). If it is cloudy then cook for 30 more minutes and retest. This recipe on high in my crock pot usually takes the full 3 hours to cook.
If you never get clear soap…this is where having Failer’s book come in handy. She goes through all of the troubleshooting and fixes for both over-alkaline and under-alkaline soap. She also discusses using phenolphthalein to test your soap. All of this is too much to go over here. A good scale is important and missed measurements account for a large part of failed batches.
Another good reason to get her book is that she talks about dilution rates. For this recipe we’re going to use equal parts paste to equal parts water. For more info on dilution rates…get the book.
When I do this recipe I usually end up with about 90 oz of soap paste. So I add 90 oz of distilled water to a stock pot and bring to a boil. Turn down heat to low and spoon in globs of the soap paste and stir. And stir. You can turn off the heat and let it sit over night. Most will be dissolved by then. If it is not all dissolved then turn the heat back on to med/low, turn off heat after it’s warmed up a bit, stir and let sit some more.
Some people use a big enough crock pot so it will hold both the paste and the water for dilutions and just set it to warm until everything is dissolved. This works as well.
Now we neutralize.
For more in-depth…get the book. I’m going to be very general here…it can get confusing.
We have a few things to consider when neutralizing our soap.
1. What are we going to use? The choices are boric acid, citric acid & borax. I typically use citric acid. Borax is good for also thickening the soap, although it is not good to use on children under 3 and broken skin so I don’t use it. Some people even say it isn’t really a neutralizer. Failor says it is…so you will have to decide.
2. Did you use potassium carbonate to make for easier stirring? If so, you’ll need to neutralize.
3. How much excess potassium hydroxide did you use? If you followed the recipe above it was about 10%, but some choose to go with a lower amount. The choice is yours, but I will detail neutralizing an excess of 10% per the Failor method.
To neutralize the potassium carbonate Failor says to use 17 parts of acid to neutralize 20 parts of potassium carbonate (or about 85 percent). So since I added 2 ounces of potassium carbonate to my lye solution I will need 1.7 oz of citric to neutralize my potassium carbonate. (This part of the book did not make sense to me. She then says to mix with 4 oz hot water. But I’ll tell you what I did later.) You still need your regular amount of neutralizer to neutralize the excess potassium hydroxide.
To neutralize the soap paste Failor says to use a 20% solution (1 part acid to 4 parts boiling water) of boric or citric acid. Make a solution with 2 oz of acid to 8 ounces of boiling water. She says to add ¾ ounce (or 1 ½ tablespoons) of this solution for each pound of paste. I ended up with about 6 pounds of paste so I needed about 9 tablespoons of this solution. (Here I have an issue with her using volume instead of weight.)
Now…why is the potassium carbonate solution a more concentrated solution than the solution to neutralize the paste? I can’t say…I’m just following Failor and that’s what she says to do
. This was the most confusing part of the process.
When I neutralize I heat the soap back up to just under boiling. Mix your acid with boiling water and add that mixture to the soap in a slow stream while mixing.
I ended up adding 9 tablespoons of the citric acid/water solution to my diluted soap. Know what about the acid to neutralize the potassium carbonate? Well, I tested my soap with phenolphthalein and it seemed pretty neutral so I stopped there afraid to do more!
I plan to buy a digital ph tester to better test liquid soap.
*Tip – before I neutralize the soap I like to take about 2 tablespoons out and put it into a glass jar. After I neutralize, I take about 2 tablespoons out and put into another glass jar. Then drop a drop of phenolphthalein into each jar and you’ll be able to see a difference in PH. YOu can see in the picture at the top there are two jars with smaller amounts of soap. The yellow one is the soap after I added citric acid and the pink one is the soap before. Each has a drop of phenolphthalein.
I let the mixture cool down a bit (still hot just not near boiling) and added my superfat ingredients, vitamin e as well as coloring and fragrance. I then put in gallon jugs and let sit for a couple of weeks. You’ll notice your soap will get even clearer as particles settle.
Bottle and enjoy!
Whew! I hope this helps you out a bit on how to make liquid soap. Like I said this is my experience and understanding. Hopefully other liquid soap makers will chime in with their tips and advice.
Amanda
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