Cold Process Liquid Soap, Start To Finish

I will try to cover everything, but I do not go over how to create a soap recipe, that will take additional research on the readers part because that sort of thing needs it’s own separate post. There are many online resources, my personal favorite is but there is also Soapee Lye Calculator. This instruction is targeted at someone who has ideally made at least one or two batches of Cold Process Bar Soap and wants to learn to make Liquid Soap.

I am using 80% Olive oil, 15% coconut oil and 5% castor oil to enhance bubbles. I have a 3% super fat. You can use other oils but you will likely get an opaque or white soap. Oils with high unsaponafiables will cloud your soap and settle to the bottom. Too much superfat will cloud your soap.

You will want to know the purity of you Potassium Hydroxide so that your recipe is calculated accurately. I know factors for 90% KOH by checking a box. I am using a water/lye ratio of 1:1.

For liquid soap making you want to add all of your additives to the water before you mix in the lye. I will be starting off with heating my water slightly and adding 1 tablespoon of salt per lb of oil. This will make your soap thicker. Once it is dissolved I add 15 mg of sodium lactate and put the water in the freezer to cool. The sodium lactate will allow the soap to dilute much faster. Sugar is also a common additive, it boosts lather but I am not using sugar in this batch.

The remainder of the soap making process requires safety equipment so here is my obligatory long winded warning.

**You should be wearing long sleeves, gloves, goggles and be in a well ventilated area with no kids or pets. You should know how lye works and have watched some lye safety videos on youtube. Make sure you don’t use metal that isn’t stainless steel and ensure that all plastics are heat safe. All spatters and spills need to be cleaned and neutralized with vinegar.  If you get lye on your skin run cold water over it right away. When you mix lye and water you ALWAYS pour the lye into the water, you DO NOT pour water into lye unless you want to burn your face off with 200+ degree face-melting-chemicals that volcano’s out of your container.**

Add the lye to the water, preferably in a well ventilated area and mix it until all of the lye is dissolved, It should get up to 160-210 degrees in just a few seconds. Let it cool to room temperature or just above. I usually set the lye container in a shallow bath of ice water to cool it more quickly. Once the lye is within 10 degrees of the room temperature oils, pour the lye water into the oil.

Use a stick blender to blend the oil/lye mixture until you reach trace, if you get something that get’s lumpy or wants to separate, don’t worry, that can be normal.

After it is thickened to a thin pudding I left it alone for a half an hour. When I came back it was thick like frosting so I used a spatula. Depending on your recipe it might need to be blended again, it might even separate a little, don’t worry if that is the case. Stir it up/blend it and let it sit for another half an hour.

It should begin to warm up and go through gel phase, I was bad at logging the temperature but you will want to place your container on a heat safe surface. After a while it will begin gel phase and look translucent, stir it up and come back in another 30 minutes or so.

Gel phase

30 more minutes.. maybe it was an hour. It stayed translucent, lost it’s lumpiness and a lot of heat and acts like Vaseline. It has cooled off by 20 degrees since the last time I checked.

At this point I covered it with plastic wrap and left it over night. In the morning it passed a zap test and my pH test strip indicated 9. You can let this sit for a few days or you can start to dilute right away. You can also store extra soap paste in a jar or zip lock bag to dilute later. Some recipes will yield solid soap instead of paste, that is also normal.

To start the dilution process you will want to add an equal amount of water, to your soap for a 1:1 dilution. Do this by matching the total weight of your recipe. Once the distilled water is added you will want to break up the soap paste into smaller chunks with a spatula.

Dilution can take a few days, Stir it up once or twice a day, if you are impatient you can put it into a crock pot on low.  I decided that since I don’t get my containers for a week to start with no heat for my first dilution and then move to a crock pot after I have a thick gel. If you have not used sodium lactate this part will take much longer and you may want to go the crock pot route but heat is not necessary for dilution, it just takes more time.

Here is that first dilution over several days.

Day 3

I diluted my entire batch 1:1 and it made a thick slime like gel with chunks still undiluted, I left it this way for about 4 days, stirring occasionally before I transferred it into a crock pot for further dilution.

Fragrances are added with the second dilution. Some fragrances and essential oils will change the clarity or thickness of your soap or more drastically it could cause your soap to separate and be ruined so now is the time to separate out a few spoon fulls of soap, dilute it in a small jar, add your fragrance and see how it reacts before doing the same with your whole batch.

During dilution I turn the crock pot on long enough to warm it up then I turn it off again. It’s best to log your dilution amounts as part of your recipe. It is always good to keep this information so you know much soap your recipe yields and at what thickness. I started with 200 grams and increase by 100 grams after each addition absorbs. This is at 300 grams. Finally those last undiluted chunks are starting to dissolve.


You can keep it thick for a body wash or you can make it thin and watery like Dr. Bronner’s liquid soap. Soapers who intend to sell their liquid soap will add a preservative, though it technically does not need one if the pH stays over 9, however liquid soap with a high ratio of water could reach a tipping point where it would need a preservative. This requires a preservative that works in high pH, Suttocide A is a commonly used option.

After letting a few more days pass, I separated out the undiluted chunks and added 600 grams of water, 100 grams at a time and I am ready to bottle. It has a nice clarity and thickness.

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