Classic Bells > Soapy stuff > Liquid soap making

Liquid soap: Tips for making

Potassium hydroxide is required

First things first. Potassium hydroxide (KOH) is the alkali needed to make liquid soap. Sometimes a bit of sodium hydroxide (NaOH) is included in liquid soap recipes, but KOH must be the main alkali if you want to make soap that can be diluted into a a stable, pourable liquid soap.

The corollary is sodium hydroxide (NaOH) is the alkali needed to make solid soap. Sometimes a bit of potassium hydroxide (KOH) is included in bar soap recipes, but NaOH must be the main alkali if you want to make acceptable bar soap.

Some people make "liquid soap" by adding water to shredded bar (NaOH) soap to create a pourable mixture. Other experienced liquid soap makers and I have tested this idea multiple times. We have found a mix of sodium soap and water might be a decent liquid soap for a few days to a week or two, but the viscosity (thickness) does not remain stable and the texture can become unpleasant. There is nothing wrong with trying this idea out, but do not be surprised if your results are not impressive in the long run.


Getting started

If you are completely new to soap making, I do not recommend starting with liquid soap. Start with solid bar soap made with sodium hydroxide and then come back to liquid soap making after your general soap making skills are honed.

If you already make bar soap and want to expand into making liquid soap, I recommend reading this article first --

Liquid Soapmaking -- Where to start by Jennifer of Miles Away Farm


Making your first batch of KOH soap paste

Build your skills by making a basic liquid soap paste following a tutorial from a reputable source. I recommend using a cold process method and making sure the recipe has a low (1-3%) superfat. Avoid recipes that require neutralization with citric acid, borax, or boric acid.

You can make soap for bathing and handwashing or you can make soap for household cleaning. Here are several tutorials that I recommend --

Susie --

Irish Lass -- See Posts 8 and 9.

Safety caution! For safety's sake, KOH should be dissolved in room-temperature water, not in hot glycerin. Please follow her directions for dissolving KOH in water. Ignore her directions for dissolving KOH in glycerin.

Christine of Alpha Omega Soaps --


Added glycerin is nice but not required

Many liquid soap recipes presented in recent years, including some of the ones listed above, include glycerin as one of the main ingredients.

Glycerin is handy because it accelerates the saponification process so the soap batter comes to trace faster, but glycerin is an optional ingredient, not a requirement.

You can convert any liquid soap recipe that calls for glycerin into a no-glycerin version. Simply replace the glycerin with an equal weight of water.


Grated handmade soap is an alternative if not using glycerin

Rather than using glycerin, you can adopt the old soap maker's trick of adding a small amount of grated handmade soap to the soap batter. The soap acts as an emulsifier to help the batter come to trace quicker. Like glycerin, the use of grated handmade soap is also optional.

I suggest using 0.25 to 1 ounce of grated handmade soap per 16 ounces (500 grams) of fats. Add this soap to the hot lye solution or to the soap batter when you mix the lye and fats together.


Substitute heat if not using glycerin or grated soap

If you do not want to use either glycerin or grated handmade soap, another alternative is to heat the soap batter to 160-180 F / 70-85 C. Adding heat is a third "trick" to help the soap batter come to trace quicker.

After bringing the soap to trace with added heat, follow the recipe instructions from that point.


Tips for success

Keep your first batches simple! Limit ingredients to the basics -- water, KOH, fat, and possibly glycerin.

Keep each batch size small A total of 100 to 300 grams of fat will make a LOT of liquid soap after it is diluted.

Do not get hung up on all changes in texture and appearance that you are "supposed" to see. Some authors provide detailed descriptions and photos of the various texture and visual changes their soap goes through as it saponifies. These changes may or may not happen to your soap. If you do not see every stage shown in the tutorial, do not fret. Just keep moving forward with the process, and your soap will very likely turn out just fine.

There is no need to cook liquid soap for hours and hours, even though I realize many recipes are written that way. Most liquid soap is fully saponified within about two hours, and often the soap is done within one hour.

Be gentle with yourself. Liquid soap making can be frustrating, especially at first. Once you get used to it, you will learn that liquid soap making is a forgiving process. If you need to take a break, simply remove the soap pot from heat (if using heat), cover the pot with a tight fitting cover, store it in a safe place away from pets and people, and let the soap sit for a few hours or even a day or two. You may return to find the soap has finished saponifying all by itself without your help.

Neutralizing liquid soap with borax, boric acid, stearic acid, or citric acid is not necessary if you use a recipe designed with a small amount of extra fat (positive superfat). (See the tutorials listed above for no-neutralization recipes.) Some liquid soap recipes, especially older ones, are designed with a small lye excess (negative superfat), and these do require neutralization. I strongly recommend you avoid these neutralization-required recipes until you are comfortable with the liquid soap making process and want to explore this alternative method.

Work your way up to more challenging projects. After making a batch or two of basic liquid soap, create your own liquid soap recipe or try more complicated recipes such as the Creamy Cocoa-Shea Glycerin Liquid Soap by Irish Lass,


What to do with KOH soap paste

Use the paste as-is. Soap paste (the thick saponified soap before it is diluted) can be used directly for general household cleaning. A 100% coconut oil soap paste is a good choice for this purpose. Put a dab of paste on a sponge or cloth for washing dishes or scrubbing the shower.

Some people pack soap paste into lip-balm-type tubes for washing hands in public restrooms. The tube of soap stores easily in a purse or pocket until a dab of soap is needed. A good recipe for this purpose would be a mild bathing-soap recipe.

Dilute to a pourable thickness. Another use for soap paste is to dilute it to a pourable consistency. See Liquid soap: Tips for diluting and thickening for more about diluting KOH soap paste.

Dilute the entire batch or dilute only what you need. Keep in mind you can dilute only a portion of the paste to meet your current needs and store the rest for later dilution. Store unused paste in a tightly closed jar or plastic bag in a dark, reasonably cool storage place. Some people even store it in the refrigerator.


Adding fragrance

Add fragrance to the finished product. If your finished product is the paste, scent the paste. If the finished product is the diluted soap, then scent the diluted soap.

Use scent with a light hand. Most people report they scent liquid soap more lightly than bar soap, so start with 0.5% to 1% by weight of the finished product and see what you think. It is easier to add more scent than it is to remove too much.

Test the fragrance first in a sample of soap to learn if the fragrance alters the texture or appearance of the soap. Some fragrances thicken liquid soap, others thin it out, a few cause the texture to become clumpy or grainy, others can cause superfat to separate from the soap, and a few scents are perfectly well behaved. There is no way to know what will happen except to test a sample.