How to Use and Thicken Liquid Soap Base
Making liquid soap from scratch involves several stages and multiple hours of cooking and diluting. If you’re interested in making your own liquid soap, I would recommend checking out the Liquid Soapmaking Book, which includes instructions and recipes to make liquid soap. Another option is to use a Premade Liquid Soap Base or Concentrated Paste. Bramble Berry carries several different varieties. Liquid soap bases cut down significantly on time, while still allowing you to create and customize a high quality liquid soap product.
One of the important characteristics of liquid soap is the texture. Liquid soap can range from very thin to a thick gel consistency. It’s important to remember that thickness does not mean concentration or quality. There is no right or wrong consistency, it’s all about personal preference. But, the texture of liquid soap does affect packaging options, and may affect how the product is used. For example, soap that has a thin or medium consistency works well in bottles with a pump top. Soap that is too thick may not work well in pump tops, but instead are better suited for disk caps.
Some of the liquid soap bases, like the Castile Liquid Soap Paste, need to be diluted before use. The recommended dilution rate is 4:1 water to paste. Diluting the soap is super simple. In a large pot, bring distilled water to a boil. It’s important to use distilled water, as tap water can have microbes or trace metals. When the water is boiling, add the paste and stir to combine. Keep the mixture around 160°F and stir the soap periodically until the paste is fully dissolved. That can take up to 8 hours depending on how much soap you’re diluting. When the soap is dissolved, let it cool and add fragrance and color if you like. We love using LabColors to color liquid soap with a transparent tint.
Customizing the consistency of thin liquid soap bases, such as the Stephenson Organic Liquid Castile Soap, is really easy. Made primarily of sunflower and coconut oil, this soap base is very gentle on the skin. If you love the formula of a thin soap such as the Stephenson Organic Liquid Castile Soap but want a thicker consistency, it’s easy to change. To thicken, all you need to do is create a salt water solution, and add the salt water to the base in small amounts. To make the solution, first mix 0.5 ounces of plain table salt (just the cheap stuff!) to 1.5 ounces of warm, distilled water. Stir until the salt is fully dissolved.
To thicken liquid soap base, first make a salt water solution.
Then, pour your soap base into a mixing container. Add a small amount of the salt water solution directly to the soap base, and stir. The amount you use will depend on how thick you want the soap to be. Adding 1 mL of the solution is usually enough to see a difference! Continue adding the salt solution (stirring in between each addition) until you reach the consistency you desire.
Add the salt solution to liquid soap base to thicken. A little goes a long way!
It is possible to add too much salt solution. The mixture will become extremely thick, similar to the texture of jelly soap! Below, 10 mL of salt solution was added to 4 ounces of soap. You can see how extremely thick it is! I could even hold it in my hand, like flubber. =)
For the sake of experimenting, I tried pouring the remainder of the 1.5 ounces of salt solution into the “flubber soap” to see if it would get even thicker. Adding that much extra liquid turned the soap into an unpleasant, watery, milky consistency. Even though it’s salt water which thickens the soap when added in small amounts, that much extra water dilutes the soap texture. Ick!
Sometimes, you don’t need to thicken soap with salt solution because your fragrance or essential oil will do the work for you. Just like cold process soap, fragrances and essential oils can cause the liquid soap to “accelerate” and become thick. Fragrance and essential oils can also affect the clarity and color of the base. I always like to make a small test batch of fragrance or essential oil in liquid soap to see how it behaves. In addition, I recommend adding your fragrance before thickening soap with salt water. After adding your fragrance, you may find it becomes thick enough.
Above, I added 3 mL of Lemongrass Essential Oil to 8 ounces of Stephenson Organic Liquid Castile Soap. As I stirred in the essential oil, the soap base become a little cloudy and immediately began to thicken. I decided to not thicken this batch more with the salt water solution, as it became nice and thick with the essential oil. The next day, the cloudiness from the lemongrass essential oil went away, and the liquid soap looked nice and clear (shown below).
Another option to thicken liquid soap base is with Liquid Crothix. Crothix is easy to use; simply add it to your room temperature soap base and mix until fully incorporated. There is no heating required. Just like using salt water solution, I recommend making a small test batch to find just the right amount of crothix for your project. The recommended crothix usage rate is 1-8% of the total weight of your product.
If you have never experimented with changing the consistency of your pre-made liquid soap base, you can see it’s extremely easy! Make sure to only use table salt and distilled water, and add the solution to the liquid soap base in very small amounts. I also highly recommend adding your fragrance or essential oil to the soap base first, as doing so can thicken the soap dramatically.