What’s the difference between homemade liquid soap and homemade bar soap besides the consistency? The type of lye that’s used in each one. By combining fatty acids and Sodium Hydroxide (NaOH), the sodium actually crystallizes to form a hard bar of soap. In liquid soap, the Potassium Hydroxide (KOH, caustic potash) is soluble, leaving it to stay soft instead of crystallizing.
I started experimenting making liquid soap quite a few months ago. The hard way. Maybe it wasn’t exactly hard, but I couldn’t wrap my head around quite a few of the processes of homemade liquid soapmaking. If you’ve landed on this page through a search engine, you know what I’m talking about! There is not a lot of information around the internet on how to make homemade liquid soap, unlike bar soap where I studied many sites for months before I made my first batch.
I had Catherine Failor’s book, Making Natural Liquid Soaps: Herbal Shower Gels / Conditioning Shampoos / Moisturizing Hand Soaps, in front of me, but it was confusing of why she was doing some of the steps. There is invaluable information included in her book–once I got beyond some points.
I want to make homemade liquid soap so I can stay away from a bunch of added ingredients. I want oil, water and lye. Maybe some fragrance. Simple. I don’t want to add solvents to clear my soap, or acids to neutralize or emulsify or thicken. I want to make simple homemade liquid soap–mix it, cook it, dilute it, use it.
My first batch took me hours to do–I used Failor’s Super Mild Soap recipe from her book. I ended up with a clear, thick liquid soap…by adding borax to neutralize, emulsify, and thicken.
I finally stumbled upon Yahoo’s Liquid Soapers Group. There are years’ worth of posts there. After studying, asking some questions, and experimenting on my own, I was finally able to understand why Failor uses a 10% lye excess in her recipes then in later steps neutralizes the excess alkali–for clear, transparent soap. That’s the only reason. I don’t mind a cloudy soap (as long as it’s not milky). Many of the liquid soaps that are on the market are not clear.
I’ve come up with a recipe and a method that is simple.
I use a small (1 pound) recipe. Smaller recipes trace and cook faster.
I’m also only using two oils–20% Coconut Oil and 80% Olive Oil Pomace. Pomace will actually trace faster than regular olive oil. With the correct oil/lye mixing temperature and the correct trace temperature, I can reach trace in 20 minutes.
My recipe is also superfatted at 3% instead of Failor’s 10% lye excess, so there is no need to neutralize with an acid.
At the end, if I deem necessary, I thicken the diluted soap by the evaporation method instead of adding anything more to it–this leaves a concentrated liquid soap.
How to make Quick & Easy Supermild Liquid Soap:
First, weigh the crock pot. This weight will be needed after cooking to calculate the dilution water needed.
Heat measured oils in a covered crock pot on high to 160°F.
When the oil is just about heated, mix measured lye into the measured distilled water. It will naturally heat to the range of 140-150°F. Our goal is 140°F.
When oils are at 160°F and lye is at 140°F, mix the lye into the heated oils slowly (almost a dribble), stirring constantly.
Now, off to trace! Turn the crock pot to low–trace will happen faster when the mixture is at (or around) 160°F. Using a stick blender, use small bursts–on, off, stirring around. Bursts actually bring soap to trace faster than constant blending. Trace with this recipe usually takes about 20 minutes.
Give the blender a rest every few minutes also, this helps prevent overheating (and burning up) the blender and it stopping in the middle of a batch.
Liquid soap trace is different than hard soap trace. We reach the hard soap trace rather quickly. But keep going!
It seems to break up into an applesauce-like consistency.
Then back into a pudding texture.
And starts to get thick.
Then, less than a minute later, VERY thick–like a taffy.
All of a sudden, the blender won’t blend. You’re done.
Let it sit for 5 or 10 minutes. Trace is reached, if after setting, there is no separation of the lye (clear liquid at bottom) and oils (usually floats to top). I cover it the crock pot…if there’s no separation, the cook period is beginning now.
If there is no separation, turn the crock pot to high and keep covered. This will give a cooking temperature range from 180°F – 200°F.
Stir every 15 minutes. Stirring is important. Unlike hard soap, where I just cover it and let it do its thing, liquid soap paste can trap air, slowing down saponification.
While you’re waiting for the paste to cook, boil the dilution water. This is added after the soap is done, but it needs to be boiling. A 1-pound batch of soap usually takes around 70 ounces of dilution water.
Soon (around 40-45 minutes), the paste takes on a vaseline-mashed-potato appearance.
Test for neutrality. This can be done with the tongue-zap test or with 60 ml 1% Phenolphthalein in Ethanol Solution Indicator. With phenolphthalein, drop 1 drop onto a small amount of soap (out of the pot!).
If it stays clear, the paste is neutral…and done. To clarify–the paste is done, but you can continue to cook it until it looks more like vaseline and less like mashed potatoes. Either way is fine! The more vaseline-like it is, the more clear the end liquid soap product it is. I was looking for a quick and easy liquid soap. I have no problem if the soap I use here at home is cloudy.
If it turns any shade of pink, there is excess alkali and it is not done. Continue cooking.
When the paste is done, weigh the crock pot (with the soap in it) and subtract the beginning crock pot weight. The result is the soap paste weight.
High olive oil recipes need a 3:1 ratio of water to paste to fully dilute without using an emulsifier. If it’s not fully diluted, the liquid will start to congeal, or thicken, on top working its way down through the soap, leaving a thick mass. Remember, since this is a simple, easy method, we’re not adding anything, so it needs to be fully diluted. To figure the exact dilution water needed, multiply paste weight by 3.
Pour boiling water into the crock pot (that is still on High). Stir around, breaking up the chunk of paste.
Cover and let sit a few minutes. Stir, break it up some more. You can leave this sit all by itself, but the process will take longer. It’s up to you! This can take anywhere from 45 minutes to an hour.
When it is fully diluted, the resulting soap is thin. It is up to you if you want to thicken it or leave as is. I personally like to keep some of the soap thin. I use it in the foamer in the bathroom. Also I keep a bottle at the kitchen sink. One squirt on the scrubby washes many dishes without filling the sink.
To thicken the soap without adding anything, put it in a pot on the stove. This will evaporate the excess water. I know this sounds insane to add all that water then evaporate it back out, but all of that water is needed so it doesn’t congeal. Leave it to simmer, scraping the sides and bottom of the pan, until it has reduced. I use a guide of about 25%…or 8 ounces down to 6 ounces (this fits in a pump bottle well).
You can also add 1-2 ounces of glycerin per pound of diluted soap for a more moisturizing, lathering, and emollient liquid soap. I have not done this. I just use the evaporation method now. BUT glycerin liquid soap is next on my list to try. It’s fast and easy, too! Liquid soap can be thickened with sodium hydroxide, also. Another experiment in the works!
To fragrance the liquid soap, add up to 2-3% of the diluted soap weight of fragrance or essential oil to hot diluted soap. You can add fragrance to the whole batch of soap in the crock pot (or pan if thickening) or pour the soap into individual jars and add a different fragrance to each one. I generally use 1 1/2 tablespoons of fragrance per quart jar. But it’s your own personal preference! This recipe make 2 3/4 quarts un-evaporated soap or 2 quarts evaporated soap.
Here's the full recipe and printable!
Quick & Easy Supermild Liquid Soap | 1# 3% Superfat
- Hot Process Liquid
- Trace Time:
- Cook Time:
- 3.2 oz Coconut Oil
- 12.8 oz Olive Oil Pomace
- 9.4 oz Distilled Water (3:1 Water:KOH)
- 3.1 oz Potassium Hydroxide (KOH)
- Fragrance -- 2-3% diluted soap weight.
- Dilution water -- 3 times paste weight.