DIY Liquid Soap (Coconut & Olive Oil)

This formulation is simple and perfect for your first time, a basic blend of common soap making oils that balance each other out.

What makes this recipe different from many others you’ll find is the slightly lower lye amount. This is intentional! While it means your soap won’t be crystal clear, it will be gentler on your skin and suitable for everyone in your family.

A Look at Each Ingredient

This recipe makes about 2.5 pounds of soap paste. When diluted 1:1 with water, you’ll get around 5 pounds of finished liquid soap – that’s roughly 10-12 pump bottles worth. 

Remember, you have to use potassium hydroxide. It’s a must and there are no substitutes!

For the Soap Base:

• 9.3 ounces Potassium Hydroxide (KOH) – this is different from regular sodium hydroxide used in bar soap
• 29.4 ounces Water (for mixing with lye)
• 31.75 ounces Coconut Oil
• 3.5 ounces Olive Oil
• 5.3 ounces Alcohol (optional but speeds up the process)

For Dilution

• 50 ounces Distilled Water

Optional Additions

• Essential oils or fragrance oils (add to taste)

Equipment

• Slow cooker: Makes the whole process much easier. Best to use a dedicated one for soap, but a thoroughly cleaned one can go back to food use.
• Stick blender: You’ll need this – whisking by hand won’t work for liquid soap. It ensures everything mixes properly and saves you from stirring for hours.
• Scale: Accuracy matters in soap making. Small measurement errors can leave you with soap that’s too harsh or won’t set right.

How to Make

Step 1: Make the Lye Solution

Put on your gloves and goggles – this stuff is serious business. Weigh out your KOH and water separately, then slowly add the KOH to the water (never the other way around or you’ll get a volcanic reaction).

The mixture will get HOT and make crackling sounds as you stir – totally normal! Just keep stirring until it’s fully dissolved. Set it aside somewhere safe to cool down. You’ll know it’s ready when it goes from cloudy to clear.

Step 2: Heat Your Oils

Toss your coconut oil and olive oil right into the slow cooker and turn it on high. If you want to speed things up, melt them in a pan on the stovetop instead, just keep it on low heat.

The coconut oil will go from solid white chunks to completely liquid. No need to get it super hot, just melted and warm to the touch is perfect.

Step 3: Let Everything Cool

This is where patience pays off. Your lye solution needs to cool until it’s completely clear, and your oils should be warm but not hot enough to burn you.

Step 4: Combine Lye and Oils

Pour that cooled lye solution slowly into your melted oils. If you’re using alcohol, add it now – it’ll speed up the whole process.

Start blending with your stick blender in short bursts. This is going to take a while if you skipped the alcohol, but keep going until you don’t see any oil streaks. The mixture should look uniform before you move on.

Step 5: Cook the Soap Paste

Turn your slow cooker to medium or high and cover it up. If you want to get fancy, cover the whole thing with plastic sheeting and secure it with a bungee cord – this keeps the alcohol from evaporating and holds the heat in better.

Now you wait. For 2-3 hours, stirring occasionally, until the mixture turns thick and translucent. It’ll look like clear playdough when it’s done. If there’s still liquid hanging around, keep cooking.

The soap is ready when it passes the zap test…touch a tiny bit to your tongue and if it doesn’t zap you, you’re good to go.

Step 6: Store Your Paste

You’ve got soap paste now! I like to store this as-is and dilute it as needed.

It keeps forever and takes up way less space than diluted soap.

Step 7: Dilute to Use

The basic rule is 1:1 – one part paste to one part distilled water. You can heat the water and blend if you’re in a hurry, but I just mix it up and let it sit overnight.

Start with less water than you think you need – you can always add more, but you can’t take it back.

Once you add water, mold becomes a possibility if you don’t use it up fairly quickly.

Step 8: Add the Extras

Want color or scent? Add essential oils, fragrance oils, or liquid colorant now. Go easy – a little goes a long way.

I never add color, but here’s how you’d do it: use a colorant specifically formulated for liquid soap. Add just a few drops after dilution when the soap is below 140°F. Adding them to the paste can result in uneven distribution or color changes during the cooking process.

Step 9: Bottle It Up

Pour into whatever containers you want to use. It’ll be cloudy at first but will clear up over the next week or two.

Remember: This will be thinner than store-bought soap, but it’s still got plenty of cleaning power. Use less than you think you need.

Customizing Finished Soap

This is a lovely clear base, for just about anything.

• To make a kitchen hand soap: Add 15-20 drops of lemon essential oil per cup of diluted soap. The bright citrus scent cuts through cooking odors like garlic and onion, while the coconut oil base provides plenty of cleaning power for dirty hands
• bubble bath: For a simple bubble bath, dilute the soap paste slightly less than normal (using about 20% less water).

How to Store It

The way you store your liquid soap makes all the difference in how long it lasts.

Undiluted soap paste is your best friend for long-term storage: it can last up to a year in an airtight container in a cool, dark place with virtually no risk of spoilage. This is because the high pH environment is naturally hostile to most bacteria and molds.

Once you dilute the paste with water, however, the clock starts ticking. Without preservatives, diluted liquid soap typically stays good for 3-6 months. You can add preservatives like Optiphen or Liquid Germall Plus after dilution.

This is why I prefer to store most of my soap as paste and just dilute what I’ll use within a month or two.

Always use distilled water for dilution, as tap water contains minerals and potential contaminants that can reduce shelf life and affect clarity. (I don’t always do this, but I should!)

Questions and Troubleshooting