How to Make Herbal Liquid Soap from Scratch {+ recipes}

Learn how to make natural herbal liquid soap from scratch. Homemade liquid soap can be used as a hand soap or body wash!

row of jars of liquid soap and liquid soap at various stages of cooking

The idea of making liquid soap from scratch used to intimidate me, but once I gave it a try, I realized it’s a lot easier than it looks!

If you’ve successfully made cold process or hot process soap before, then you can make liquid soap.

The following article was originally a section in my newest print book, The Big Book of Homemade Products for Your Skin, Health & Home. However, it got cut during editing because we ran out of space, so I thought I’d share the information and recipes here instead. :)

Some links on this site are affiliate links; I only recommend products I personally use and enjoy. As an Amazon Associate, I earn from qualifying purchases.

glass soap pump of herbal liquid soap on a wooden board and plantain leaf and grass covered ground

Liquid Soapmaking Tips

Here are a few key things to keep in mind before diving into liquid soap making.

You’ll need a different type of lye:

One key difference between liquid soap and bar soap is the type of lye used.

Bar soap hardens because it contains sodium hydroxide (NaOH) as the agent that turns oils into soap.

Liquid soap is created by combining oils with potassium hydroxide (KOH), which can be purchased from Etsy or online soap-making supply stores.

The purity level of potassium hydroxide can vary; my recipes are based on 90% purity, which is a commonly available type.

If you have a different purity listed on your bottle, input your recipe at Soapee and change the lye purity number in the first box, after selecting “Liquid Soap – using KOH”.

Superfat is a little different than bar soap:

Liquid soap is also slightly different in that it requires a lower superfat, usually no higher than 3% or the soap may develop an oily layer.

You’ll need to use more water in your recipe:

The water amount is somewhat higher when making liquid soap: you’ll need about three times as much water as the weight of the potassium hydroxide amount.

It’s a good idea to dilute soap paste only with water and/or glycerin:

Be sure to dilute the finished soap paste with only water or a combination of glycerine and water so your soap has the longest shelf life.

Don’t dilute with herbal teas or milk; unless they were cooked into the recipe (such as with the Calendula & Coconut Liquid Soap below), or the soap will more easily spoil.

Oils act differently in liquid soap than bar soap:

When creating your own recipes, keep in mind that using more olive oil makes for a thicker soap, while using more coconut oil makes for a thinner soap.

Check this great post in the Soapmaking Forum for more information on oils and liquid soap.

You have lots of herbal options:

There are many herbs that you can use besides the couple I have listed in the recipes below. They are substitutable, or could be left out completely and plain oils & water used in place of infused oils and infused water/herbal tea.

I’m working on a resource that I’ll fill in here when done, but until then, a few herbs and flowers to consider exploring include:

  • chamomile
  • plantain
  • calendula
  • dandelion
  • sunflower
  • violet leaf

My way is not the only way:

This should probably be top of the list, but keep in mind that this is how I make liquid soap. It’s not the one and only method, or even the best method – it’s just one method of several options.

There are tons of great resources on making liquid soap out there. Here are a couple to explore for further information:

Liquid Soap Making Overview

Step 1

Weigh the recipe’s oils into a slow cooker and turn the heat on high. If using milk powder, briefly blend it into the combined oils using an immersion blender.

Step 2

Place the distilled water or cooled herbal tea in a stainless steel or heatproof plastic container. Wearing gloves and goggles, weigh out the potassium hydroxide and sprinkle it into the water. Stir well. The lye solution may make a crackling noise when it’s first mixed together, but that’s normal.

crock pot with liquid soap at trace
Liquid Soap at Trace

Step 3

Turn the slow cooker’s heat to low, then pour in the lye solution. Hand stir the mixture for about 5 minutes until incorporated, then start blending with your immersion blender. Mix with the immersion blender for 1 minute, then let the blender rest for a few minutes before blending again for another minute. Don’t try to run the motor continually or you’ll burn it out. It may take 10 to 20 minutes before trace is reached.

liquid soap in crockpot after 30 minutes of cooking, it's puffed up and has glycerin streaks in it
Liquid Soap after 30 Minutes of Cooking

Step 4

Keeping the heat on low, cover the slow cooker with its lid and check every 20 to 30 minutes, stirring with a heatproof spoon or spatula. The soap will turn dark and gel-like in spots, with other areas of clear or cloudy liquid separation. This is normal; just stir everything back together, cover with the lid and continue cooking.

liquid soap at the vaseline stage
Liquid Soap at Vaseline Stage

Step 5

After 1 to 2 hours, the soap batter should be thicker and more concentrated. Continue cooking another 30 minutes to 1 hour or until the soap is glossy and resembles vaseline, as shown in the photo. Total cook time for liquid soap may vary between 2 to 4 hours, because slow cookers also vary in their baseline temperatures.

Step 6 (optional)

When you think the soap is done, you may wish to perform an old-fashioned zap test, to ensure there is no extra lye left in the soap.

To do so, scoop out 1 teaspoon (5 ml) of soap paste and let it cool to a comfortable temperature that won’t burn you. Mix the cooled paste with 1 teaspoon (5 ml) of distilled water. Dip your fingertip into the diluted paste and taste it with just the tip of your tongue, but don’t eat or swallow the soap! If it gives your tongue an electric or zapping feeling, then it needs to cook longer. If it tastes like you just licked soap, but no zappy feeling happened, then it’s ready. Rinse your mouth out well with cold plain water afterwards.

If you don’t wish to taste the soap, but aren’t sure if the soap is ready, you can turn off the covered slow cooker and keep the soap in it for 6 hours, or overnight, allowing it to finish saponifying on its own, then proceed with the recipe.

liquid soap paste in jars

Step 7

Store the paste in covered jars if you’d like to dilute small amounts at a time, or you can dilute the entire batch at once. The advantage to diluting a small amount at a time is that the undiluted soap paste has a very long shelf life of possibly several years. Once you dilute the soap, the shelf life will be more limited.

The pH of finished diluted soap runs around 9 to 10.5. Because of its natural alkalinity, it doesn’t necessarily need a preservative for home use, as long as you dilute with only distilled water and/or vegetable glycerine. (Those who sell liquid soap often add a preservative such as Liquid Germall Plus, or some like to add it “just in case” – I don’t add any to my soaps, but the choice is completely yours.)

Step 8

To figure out a starting point for dilution amount with a recipe, weigh the fully cooked soap paste and multiply the weight by 0.2 (or 20%) to get the amount of glycerine needed, then multiply the weight of the soap paste by 0.8 (or 80%) to determine how much distilled water you need.

For example, if your soap batch weighs 30 ounces (850 g), you would need 6 oz (170 g) glycerine and 24 ounces (680 g) distilled water.

If you’d like to dilute a smaller amount at a time, such as 4 ounces, you would dilute it with 0.8 oz (23 g) glycerine and 3.2 oz (91 g) distilled water.

If you don’t have glycerine available, or don’t wish to use glycerin, it can be omitted. Just use more distilled water in its place.

Step 9

Combine the glycerine and distilled water in a deep stainless steel saucepan and bring to a boil. Scrape the soap paste into the boiling glycerine-water mixture, stir briefly and gently so the paste is covered by liquid as much as possible, then cover the pan and turn off the heat, leaving the pan on the still-hot burner.

Allow the mixture to cool to room temperature, occasionally stirring and briefly mashing with a fork, spatula or potato masher. Once cooled, repeat the process 1 to 2 times by bringing the mixture back to a boil and then cooling again, stirring occasionally to break up larger lumps of soap paste.

Keep the soap at room temperature in the covered stainless steel pan for 2 to 3 days, stirring occasionally, until all of the soap paste is dissolved. The diluting process will take quite a bit of time, don’t try to rush this step or mix too vigorously in an effort to speed it up.

Step 10

To scent the soap, gently warm the soap a final time, but don’t allow it to simmer or come to a boil. Once it has warmed up (I aim somewhere in the ballpark of 100 degrees F), stir in the essential oil.

To calculate the amount of essential oil you need for the diluted soap, multiply the amount by 1% (0.1) for a 1% dilution rate. (You can go higher to 2%, but this is a good starting point.)

For example, if you have 8 ounces (237 ml), or 1 cup, of diluted soap base, you would use 0.08 ounces or 2.4 ml essential oil for a 1% rate. There are 2.5 ml in ½ teaspoon, so in this case, I would round slightly and add ½ teaspoon total essential oils to my warmed liquid soap.

Alternatively, I suggest going to EO Calc and figuring an even more precise amount that you can weigh by grams.

Some essential oils, such as lavender, are pretty well behaved in liquid soap. Others are more prone to cloudiness or separation. You may wish to use a solubilizer to keep the essential oils mixed. (A future article with more details on adding essential oils to liquid soap is in the works – stay tuned!)

Step 11

Pour the diluted soap into jars using a fine mesh strainer to catch stray undissolved lumps. Allow the soap to sit undisturbed for several days so that it has time to settle and clear, though you could technically use it right away if you’d like.

Liquid Soap Recipes

Here are two recipes to start your liquid soapmaking adventure; you can also find a recipe for Dandelion & Honey Liquid Soap already published on my site.

Use the Soapee Calculator, the information in the tips at the beginning of this article, and your imagination to create new liquid soaps to try out!

soap pump with calendula infused liquid soap on a wooden background with vase of yellow flowers in background


Calendula & Coconut Liquid Soap

This soap reminds me of sunshine in a jar. The pretty yellow color is naturally obtained by using calendula flower–infused coconut oil in the recipe.

I blended a touch of coconut milk powder in the oils for extra nourishment and label appeal, but you could choose to use cow or goat milk powder instead, or leave it out completely.

I recommend using small amounts of milk powders when making liquid soap because the long cook time can darken or scorch fresh milk.

Don’t try diluting soap paste with fresh milk; it can spoil pretty easily.

See my article Calendula Oil & Salve for information on making calendula infused oil.

Yield: 60 ounces (1.7 kg) diluted soap

  • 13.75 oz (390 g) distilled water
  • 4.63 oz (131 g) potassium hydroxide (3% superfat)
  • 8 oz (227 g) calendula-infused coconut oil (40%)
  • 3 oz (85 g) castor oil (15%)
  • 9 oz (255 g) high oleic sunflower oil (45%)
  • 1/2 tsp coconut milk powder
  • Up to 6 oz (170g) vegetable glycerine, for dilution (or more distilled water)
  • Up to 24 oz (680 g) distilled water, for dilution
  • Equal amounts of orange and grapefruit essential oils (see step 10 in The Liquid Soap Making Overview, above, for how to calculate amounts needed)

Place the water in a stainless steel or heatproof plastic container. Wearing gloves and goggles, weigh out the potassium hydroxide and sprinkle it into the water. Stir well. Set the lye solution aside while you prepare the oils.

Weigh the coconut, castor and sunflower oils into a slow cooker. Blend the coconut milk powder into the combined oils using an immersion blender. Turn the heat on low, then pour in the lye solution. Alternate blending with the immersion blender and mixing by hand until trace is reached.

Keeping the heat on low, cover the slow cooker with its lid and check every 30 minutes, stirring with a heatproof spoon or spatula. Cook approximately 2 to 3 hours. Store the paste in covered jars. Dilute and scent the soap according to the guidelines in the full Liquid Soap Making Overview above.

glass soap pump of herbal liquid soap on a wooden board and plantain leaf and grass covered ground

Hemp & Plantain Liquid Soap

This soap features a combination of plantain-infused coconut oil, extra virgin olive oil, and nourishing hemp oil. It’s lightly scented with lavender essential oil, but could easily be left unscented instead.

See my article 10 Things to Make with Plantain for directions to make plantain infused oil.

Recipe note: I used a rich green unrefined hemp seed oil from Mountain Rose Herbs to help give this soap a subtle green hue.

Be aware that hemp seed oil has a shorter expected shelf life, so I recommend using this soap up within 4 to 6 months. As reference, I have a jar of this exact recipe that’s over a year old and the green has faded to a more brown shade (though the soap still smells good), so be aware of that possibility if you don’t use it up sooner than later!

Yield: 60 ounces (1.7 kg) diluted soap

  • 13.75 oz (390 g) distilled water
  • 4.63 oz (131 g) potassium hydroxide (2% superfat)
  • 7 oz (198 g) plantain-infused coconut oil (35%)
  • 2 oz (57 g) castor oil (10%)
  • 6 oz (170 g) extra virgin olive oil (30%)
  • 4 oz (113 g) high oleic sunflower oil (20%)
  • 1 oz (28 g) unrefined hemp or avocado oil (5%)
  • Up to 6 oz (170g) vegetable glycerine, for dilution (or more distilled water)
  • Up to 24 oz (680 g) distilled water, for dilution
  • Lavender essential oil (see step 10 in the Liquid Soap Making Overview above for how to calculate amount needed)

Place the water in a stainless steel or heatproof plastic container. Wearing gloves and goggles, weigh out the potassium hydroxide and sprinkle it into the water. Stir well. Set the lye solution aside while you prepare the oils.

Weigh the coconut, castor, olive, sunflower and hemp oils into a slow cooker. Turn the heat on low, then pour in the lye solution. Alternate blending with the immersion blender and mixing by hand until trace is reached.

Keeping the heat on low, cover the slow cooker with its lid and check every 30 minutes, stirring with a heatproof spoon or spatula. Cook approximately 2 to 3 hours. Store the paste in covered jars.

Dilute and scent the soap according to the guidelines in the full Liquid Soap Making Overview above.

Looking for more creative ways to use flowers and herbs? Check out my Big Book of Homemade Products for Your Skin, Health & Home!

Available from your favorite bookstore or the following book sellers:

Jan
 

Jan Berry is a writer, herbalist, soapmaker, and bestselling author of The Big Book of Homemade Products, Simple & Natural Soapmaking, and Easy Homemade Melt & Pour Soaps. She lives in the Blue Ridge Mountains with her family and a menagerie of animals, where she enjoys brainstorming creative things to make with the flowers and weeds that grow around her.

  • Claudia says:

    Hi Jan,

    I put your info into both SoapCalc and Soapee Calculators and the water amount is a lot less than what you have listed 215.5 gr. vs. 390 gr. of water. I did say KOH so I’m not sure why such a big discrepancy? I hope you can help clear this up. Should the Water as % of oils be changed for Liquid soap?

    Thanks,
    Claudia

    • Jan says:

      Hi Claudia! With this method of liquid soap, you want to use three times the amount of potassium hydroxide. I rounded a tiny bit to get a more even number, but triple the lye weight is where you want to aim for.
      You can set the lye calculator to a 3:1 water:lye ratio. (Or you could leave the water as is, and multiply the lye weight by 3.) :)

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