A simple homemade dish soap recipe with long-lasting fluffy bubbles that get dishes squeaky clean. Perfect for the natural and zero-waste home.
I’ve been making handmade soap for over ten years but in all of that time, I’ve focused on body soap. Cold-process bar soap for whole-body use, and liquid hand soap for filling up pump dispensers. Natural cleaning doesn’t stop with personal care though, which is why I’m sharing how to make homemade dish soap. Unlike most body soap, this recipe creates very hard bars that are long-lasting and extremely effective at cutting through grease. It leaves dishes clean and sparkling while also being unscented, palm-oil free, Vegan, zero-waste, and best of all, 100% natural.
This recipe makes four to six bars of dish soap and the method is a very simple cold-process recipe. There’s a unique adjustment for the amount of lye you’ll use, and the two fats used are not in a proportion that you typically see in a soap recipe. Together, they create a soap that’s ready to use after two days and that has a thick sparkling lather for cleaning pots, pans, utensils, and dishes.
Cold-process dish soap
Most of the time when you make cold-process soap you add a superfat. This is a percentage of extra oil that does not saponify (change into soap) and stays free-floating in your bars. This extra oil makes body soap conditioning and gentler on the skin, but it can also leave an oily residue on dishes. When making cold-process dish soap you make the bars with 0% superfat to avoid this issue. Homemade dish soap also needs to have a much higher cleansing power than body soap, which is why this recipe is 70% coconut oil and 30% soy wax.
Soy wax is high in stearic acid and helps create a soap that has a long-lasting and stable lather. Stearic acid also helps bar soap to last longer when it becomes wet. Coconut oil, on the other hand, is highly cleansing, and most soap recipes tend to include it at a rate of about 25%. Sometimes a bit more, and sometimes a bit less, depending on your skin type and the superfat. You can make pure coconut oil soap but it needs a very high superfat and a long cure time.
In this dish soap recipe, coconut oil is used at 70% and creates a soap that can clean dishes (and your skin!) of oil. If you have sensitive or dry skin, I’d recommend using washing-up gloves when doing the dishes with this homemade dish soap.
Using Citric Acid in Soap Recipes
Soap scum is bad enough in the shower, but it’s even worse on dishes. That’s why we add citric acid to dish soap recipes. Citric acid is a naturally fizzy substance that you often find in bath bombs; it’s also antibacterial and has a host of other useful properties. The magic of citric acid in soap making comes down to how it reacts with lye though. That reaction creates sodium citrate, a chelator that greatly reduces soap scum.
However, citric acid can also neutralize lye in cold-process soap making. What that means is that each gram of citric acid will neutralize 0.624 g of sodium hydroxide (source). Because this recipe uses 14 g of citric acid, we need to compensate by adding an extra 8.736 g of sodium hydroxide. If you fail to do this, then your soap will have a superfat of about 11%. Meaning that 11% of your oils do not turn into soap and that when you use the dish soap it will be slippery on your dishes and may leave a greasy residue.
Don’t worry though, I’ve worked out the difference and have worked it into the recipe.
Washing dishes with homemade dish soap
The bars this dish soap recipe makes are pure white, very hard, and very brittle. Though you can pour the soap batter into a mold for traditional bars, pouring the soap into ramekins is even better. They’re perfect little containers that both store the soap and give you a surface to hold onto when creating the lather. After use, you can conveniently set them next to the sink or in a cupboard for the next time you wash up. Soap and soap dish in one! The ramekins I’m using are glass and the type that some desserts come in at the supermarket.
Washing dishes with homemade dish soap is a little different than using liquid dish soap. First of all, the soap is solid so you’ll need to work up a good lather on the brush. At this point, you can either wash the dishes with the brush or add the lather to your basin of hot water. The lather can be a little more slippery than conventional dish soap and you should thoroughly rinse the dishes with water before leaving them to dry. Without that rinse, it’s possible to get a soapy residue on your dishes and it’s particularly noticeable with glasses.
Storing Zero-Waste Dish Soap
Homemade dish soap using my recipe has a zero percent superfat. That means that it’s extremely good at cleaning dishes while not leaving an oily residue. It also means that there are no extra oils floating around in the soap to go rancid. Once made, this soap has an indefinite shelf life but once you begin using a bar, make sure to use it all within six months. Until you use a bar, keep it stored in a place that’s dry and room temperature.
Handmade soap is best stored in the open, rather than in a sealed container. There is natural glycerin in handmade soap, and if you store it in a sealed container it has a tendency to draw moisture to it. However, beeswax wraps are breathable and will protect the soap from dust and spills. Simply fold the wrap over the soap and ramekin, and store it until needed.
Homemade Dish Soap Recipe
- Stainless steel pan
- Glass or ceramic ramekins
- Prepare your workstation with your tools and equipment. Put on rubber gloves, eye protection, and an apron. Carefully pre-measure the ingredients. The oil and wax into the pan, and the lye, 2x distilled water amounts, and citric acid into each of the four jugs.
- Prepare the ramekins by washing and drying them thoroughly and setting them on a sheet of greaseproof paper. The ones I'm using came from a supermarket dessert pack and are 3¼" in diameter. At that size, you'll be able to perfectly fill four ramekins. If your ramekins are smaller, prepare a few extra and I imagine you can get six, or possibly more dish soaps. You can also pour the soap into ordinary molds but the soap hardens very quickly so I'd advise silicone cavity molds. If you use a loaf mold and cut the soap after two hours (or so) of making it, then it will crack and break as it's very brittle.
- Next, dissolve the lye (sodium hydroxide) crystals in water designated for the lye solution. In an airy place, outdoors is best, pour the lye crystals into the water and stir well. There will be a lot of heat and steam so be careful. Try not to breathe it in. Leave outside in a safe place, or in a shallow basin of water to cool.
- While the lye solution is cooling, make the citric acid solution. Pour the citric acid into the water set aside for it. Swirl and stir until the citric acid is fully dissolved. This can take up to a minute as the water will be room temperature.
- Melt the coconut oil and soy wax in a stainless steel pan on very low heat. When melted, remove from the heat and set on a potholder. Pour in the citric acid solution and stir together well. You'll notice the citric acid solution beading up at the bottom of the pan. This is normal and simply because oil and water don't naturally mix.
- Measure the temperatures of the lye-water and the contents of the pan. You should aim to cool them both to be about 125°F / 52°C*. The lye solution can be slightly higher than this but try not to soap at lower temperatures for this recipe.
- When the temperatures are just right, pour the lye solution into the pan of oils.
- Dip your immersion blender into the pan and with it turned off, gently stir the mixture. Next, bring it to the center of the pan, and with both your hands, hold it on the bottom of the pan and blitz it for just a couple of seconds. Turn it off and stir the soap batter, using the blender as a spoon. Repeat until the mixture thickens up to 'Trace'.
- Trace is when the soap batter leaves a distinguishable trail on the surface. The consistency will be like thin custard. Trace happens very quickly in this recipe so please be prepared.
- Working quickly, pour the soap into the ramekins. Give them a tap to settle the soap.
- Leave the soap in a place that it won't be disturbed for two days. Saponification will be complete and you can begin using dish soap from that point. However, soap always performs better if you leave it to cure for at least 28 days.
- To use your homemade dish soap I'd recommend using gloves, as the soap may be too cleansing for your hands. Wet the soap and work up a lather with a dish brush or scourer. When you have a good lather, use it to wash dishes or to add to your washing up water. Rinse dishes thoroughly with fresh water before drying.