How To Make A Simple and Frugal Liquid Dish Soap (With Video)

If you’ve never made soap before, you can start here. Liquid soap is often considered to be more advanced than cold process bar soap, but really it isn’t. It’s just different.

When you’re done you’ll have a lovely, simple dish soap that works just as well as any name brand concoction. And (my favorite part!) you can fragrance it however you’d like and pour into a pretty bottle and it will be clear instead of alien green or blue.

Ingredients and Tools You’ll Need

The thing about soap making is the ingredients all serve a very specific purpose. There is no substitute for lye, it’s what makes the whole thing work. The oils in soap can be substituted, but for this particular recipe, you really need the coconut oil. It is the most cleansing and most affordable.

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EQUIPMENT

• Slow cooker
• Stick blender
• Heat-safe glass or plastic container for mixing lye
• Stainless steel or heatproof plastic mixing spoon
• Gloves, goggles, and safety gear
• Scale (for accurate weighing)
• Thermometer
• Bungee cord (optional, for sealed cook)
• Mason jars or bottles for storage

INGREDIENTS

FOR MAKING THE SOAP PASTE

• 35.3 ounces coconut oil 
• 10 ounces potassium hydroxide
• 31.7 ounces water
• 5.3 ounces alcohol 90%

FOR DILUTION AND FRAGRANCE

• 53 ounces dilution water (distilled water is best)
• 1 ounce lemon essential oil
• A bulk container for storing the paste
• A pretty bottle for the finished product (I am absurdly picky about this and have bottles from this collection, but it often goes out of stock. I have also used Dawn bottles and removed the sticky labels.)

How to Make Liquid Dish Soap

Step One: Measure Water and Lye

Getting your measurements right is absolutely crucial for soap making success. You can’t eyeball it or use measuring cups! Place your container on the digital scale, tare it to zero, and weigh exactly what the recipe calls for.

And before you even start, put on those safety gloves and goggles. Lye is seriously caustic and can cause burns or blindness if it splashes on your skin. I am a bad example for this but I want you to be safe.

Don’t do this if you’re in a rush, or distracted. That’s how mistakes happen.

Step Two: Mix Lye and Water Together Very Carefully

This is where the chemistry begins! Pour the water into a heat-safe container first (never the other way around: remember the saying “snow falls on the lake” to get the order right). Then slowly add the lye to the water, pouring in a thin stream. Stir gently but thoroughly with a heat-resistant silicone spatula or wooden spoon until the lye completely dissolves.

The solution will heat up dramatically and release fumes, so work in a well-ventilated area or near an open window. It will also make a crackling sound! This is normal. Now set it aside somewhere safe to cool while you move on to the next step. The solution needs to cool to about 100-110°F before we can use it.

Step Three: Melt the Coconut Oil

Weigh out exactly 1000g (35.3 oz) of coconut oil and place it in your slow cooker. If your coconut oil is solid, don’t worry about chopping it up – it will melt just fine. Turn the slow cooker to high and let it do its thing until the oil is completely melted and reaches about 140°F (60°C). This usually takes around 30 minutes, but use a thermometer to check rather than just eyeballing it.

Once melted, turn off the slow cooker. The residual heat will keep the oil at the right temperature while your lye solution continues cooling.

Step Four: Mix the Lye Solution With Oil

Once both your lye solution and coconut oil are at the right temperature (100-110°F for the lye solution, coconut oil can be slightly warmer), it’s time to bring them together. Slowly pour the lye solution into the melted oil in your slow cooker. If you’re adding alcohol, now’s the time to do that too.

Now grab your stick blender. Start by stirring manually to incorporate everything, then use the stick blender in short 30-second bursts, giving it a rest between bursts to prevent burning out the motor. The mixture will start to thicken and might go through a “rice pudding” stage where it looks grainy: that’s normal! Keep blending until you reach a very thick trace. This is completely different than a cold process trace. It will look like thick pudding and there should be no visible oils.

Step Five: Cook the Soap Paste

Now we enter the most hands-off part of the process. Put the lid on your slow cooker and secure it – I usually place a heavy cookbook on top and wrap a bungee cord around the whole thing. This prevents any expansion and potential overflow. Turn the slow cooker back to high and let it cook for 2-4 hours.

During this time, the soap will go through several phases, from thick and opaque to a translucent gel-like consistency. The exact time varies based on your slow cooker’s temperature, but you’re looking for a paste that’s translucent like petroleum jelly.

Step Six: Check Occasionally

Every hour or so, carefully lift the lid and give the mixture a gentle stir. You’re looking for that translucent quality throughout the entire batch. Once you think it’s done, it’s time for the “zap test.” After turning off the heat and allowing the soap to cool slightly, dampen your finger, touch a small amount of the paste, and very lightly touch it to the tip of your tongue. If it “zaps” like a battery, it needs more cooking time. If it just tastes like soap, congratulations! Your soap paste is ready. I know this is weird, but it’s the best and simplest way to know if it’s done.

Step Seven: Store Until Ready to Dilute 

Once your soap paste passes the zap test, it’s ready to be stored! Let it cool enough to handle, then transfer to clean glass jars with tight-fitting lids. The wonderful thing about soap paste is that it keeps for a LONG time, easily a year or more ,with no preservatives needed.

The high pH and lack of water creates an environment where bacteria simply can’t thrive. Store your jars in a cool, dark place until you’re ready to dilute some for use.

Step Eight: Dilution

Whenever you need liquid soap, simply combine soap paste and distilled water in a 1:1 ratio in a clean container. Technically you should use distilled water, but I do not. I like to cut the paste into small chunks to speed up the process. Let this mixture sit overnight.

By morning, most of the paste will have dissolved into a lovely liquid soap. If you’re in a hurry, you can gently heat the mixture to speed up the process, stirring occasionally. Once fully dissolved, add a few drops of lemon essential oil for a fresh scent and some antibacterial properties.

Step Nine: Sequester

This step is optional but makes a difference in the appearance of your soap. After dilution, let your liquid soap sit undisturbed for 1-2 weeks. During this time, any cloudiness will gradually settle, and your soap will become clearer. This doesn’t affect how well it cleans: it’s purely aesthetic.

Storage Instructions

Store undiluted soap paste in clean glass jars with tight-fitting lids for up to a year.

For diluted soap, use pump bottles or squeeze bottles and use within 3 months.

This soap works beautifully in foaming dispensers: just use a more diluted ratio (about 1:3 paste to water).

Other Ways to Use Your Dish Soap Paste

• All-purpose spray cleaner: Dilute 1 tablespoon of soap paste in 2 cups of warm water and add 10 drops of tea tree or lemon essential oil. Fill a spray bottle and use for countertops, bathrooms, and quick clean-ups. The coconut oil’s cleaning power works WONDERS on kitchen grease!
• Foaming hand soap: These fancy dispensers aren’t just for store-bought soap! Mix 1 part soap paste with 3 parts water, add a few drops of your favorite essential oil, and fill your foaming pump dispenser. Saves money and avoids all those single-use plastic bottles.
• Laundry spot treatment: Make a concentrated solution (2:1 soap paste to water) and keep it in a small jar with an old toothbrush nearby. Dab onto stains before washing. It’s especially effective on grease spots and collar grime.
• Shower cleaner: Coconut oil soap naturally cuts through soap scum. Mix equal parts soap paste and white vinegar with enough water to make a spreadable consistency. Apply to shower walls, let sit for 10 minutes, then scrub and rinse.
• Floor cleaner (for tile and laminate): Add 2 tablespoons of diluted soap to a gallon of warm water for clean, streak-free floors. Don’t use on hardwood.
• Fruit and veggie wash: A very diluted solution (just a pea-sized amount of paste in a bowl of water) makes a great produce wash that rinses clean with no residue or taste.

Making Bar Soap vs. Liquid Soap

If you’ve made bar soap before, you already know most of what you need! It’s still a matter of lye water + oils + blending.

• Different type of lye: Bar soap uses sodium hydroxide (NaOH). Liquid soap needs potassium hydroxide (KOH). This one switch is what makes your soap stay soft instead of hardening. Don’t mix them up!
• Always hot process: Unlike bar soap which can be made cold process, liquid soap ALWAYS needs to be cooked.
• Longer to reach trace: Liquid soap takes longer to thicken up than bar soap. Be patient with your stick blender – it will get there! It might look like applesauce before it turns to pudding consistency.
• Two steps instead of one: Bar soap is a mix-pour-cut-cure process. Liquid soap has two separate stages: making the paste first, then diluting it later when you’re ready to use it. This means you can make one big batch and have soap for months!
• Ready to use right away: Bar soap needs 4-6 weeks to cure. Your liquid soap paste is ready right after cooking (once it passes the zap test), though letting it sit after diluting helps it clear up.
• Lower superfat: Bar soap often has extra oils added for moisture. Liquid soap (even a kind used for skin), will never go above 4% or so.

More Practical Soap Recipes

• A basic liquid soap that’s suitable for skin is all you need to say goodbye to store-bought soap forever.
• If you strongly prefer bar soap (it’s a little less fussy), I have a bar dish soap recipe as well.
• And to keep my your kitchen sink, there’s nothing more cheerful than a cold process lemon soap.

Questions and Troubleshooting

Printable Recipe