Simple and natural cold process soap recipe. Uses four eco-friendly oils and includes easy to understand soap making instructions
Today it’s back to basics with a simple cold process soap recipe. The bars you make with it are very gentle on the skin, palm-oil free, and eco-friendly. I even share how to reuse a drinks carton to use as a mold. Everything about this recipe ensures that the end product is good for you and the planet.
I know that a lot of people are hesitant to make cold process soap so I’ve made the recipe as easy to follow as possible. It includes only four soap making oils, water, and Sodium hydroxide. No fragrance, no additives, nothing extra. Simples. Soap making can be expensive, so the fewer ingredients you use, the more money you’ll save. It makes the soap making process easier too.
Eco-friendly cold process soap
One ingredient that you’ll come across a lot in cold process soap recipes is palm oil. It’s linked to deforestation, climate change, and obesity (as a major ingredient in junk food). I avoid it altogether in this recipe, though I’d argue that using sustainable palm oil is not a bad thing. It’s also a Vegan recipe since there are no animal products included. If you’d like for the recipe to be even kinder to the planet and your health, use organic oils.
Another way I’ve tried to make this recipe low-impact is by using a recycled mold. Not a purpose-made soap mold, but an old drinks carton that would have probably ended up being discarded. Though Tetrapak is technically recyclable, it’s debatable as to whether it’s worth the effort. Reusing them this way gives them a second life.
Great for naturally coloring soap
There’s another reason that I’m sharing this recipe. The bars it creates are nearly pure white and absolutely perfect for coloring with natural ingredients. Many soap recipes include oils and butters that are naturally a deep yellow or even greenish-yellow in color. This color survives the soap making process so any color you add could blend with it. For example, if you added blue woad powder to this yellow olive oil soap recipe, you’d get green soap! But with white soap, your colors will come through true and bright.
If having pure white bars is important for you, make sure to use pomace olive oil instead of extra virgin olive oil in the recipe. The latter is not only more expensive but is far darker in color. Plus, it’s my opinion that pomace olive oil is more eco-friendly than the EVOO in soap making. It’s extracted using a technique that eeks every last drop out of the olive pulp, making sure nothing goes to waste. Though it’s lower grade for food, it’s perfect for soap.
Easy cold process soap making instructions
There are only ten real steps in the recipe below. I don’t count the prepping step or the last item that explains about shelf-life. That means only ten sets of instructions on how to make eco-friendly cold process soap from scratch. The most difficult step to understand is when to stop stick blending and what ‘trace’ looks like. The photo above should help you see what the soap should look like at that stage. Also, this recipe is unscented but it you wanted to add essential oils, use this chart to figure out how much of each to use.
I’ve tried to make each as easy to understand as possible but if you’re still unsure, have a read through the Natural Soap Making for Beginners Series:
Eco-friendly Cold Process Soap Recipe
- Stainless steel pan for melting the solid oils
- A large bowl for measuring the liquid oils into
- Empty milk or juice carton
- Prepare your workstation with your tools and equipment. Put on rubber gloves, eye protection, and an apron. Carefully pre-measure the ingredients. The solid oils into the pan, the liquid oils into a jug, the water into another heat-proof jug, and the lye in another container.
- Prepare your recycled soap mold. Rinse out an empty drinks carton and let it dry upside down. When fully dry, cut out the side that the pouring spout is on. A cutting blade is better for this than scissors. Use a piece of the cut-out material to block the open end of the carton. This helps to create a flat surface on that side of the mold, rather than a funky shape from the shape of what was the top of the carton.
- Next, dissolve the lye (Sodium hydroxide) crystals in water. 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.
- Melt the solid oils in a stainless steel pan on very low heat. When melted, remove from the heat and set on a potholder. Pour in the liquid oils. If you have the olive and castor oils in the same container, stir them together first before pouring into the pan. Castor oil is pretty sticky and it's easier to pour when mixed with a lighter oil.
- Measure the temperatures of the lye-water and the oils. You should aim to cool them both to be about 95°F / 35°C.
- Pour the lye solution into the pan of oils. I recommend pouring the liquid through a sieve to catch any potential undissolved lye.
- Dip your immersion blender into the pan and with it turned off, 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 seconds. Turn it off and stir the soap batter, using the blender as a spoon. Repeat until the mixture thickens up to 'Trace'. This is when the batter leaves a distinguishable trail on the surface. The consistency will be like thin custard.
- Working quickly, pour the soap into the mold. Give it a tap to settle it.
- For a truly pure white soap through and through, place the soap in the refrigerator and leave it there overnight. You can also leave the soap sitting on the counter during this time. If the house is warm, there's a small chance of the center gelling, and your bars having slightly darker centers though.
- The next day, take the soap out of the fridge and set someplace to rest for another day. Once 48 hours have passed, you can take the soap out of the mold and cut it into bars using a kitchen knife. You can get six to eight decent-sized bars of soap from this batch.
- Cure it for 28 days. Curing means leaving the bars spaced out on a protected surface out of direct sunlight and in an airy place. This allows the extra water content to fully evaporate out. Here are full instructions on how to cure soap.
- Once made, your soap will have a shelf-life of up to two years. Check the oil bottles that you're using though -- the closest best-by date is the best-by date of your soap. If your handmade soap is destined as gifts, check out these eco-friendly soap packaging ideas.
More Cold Process Soap Recipes
- Learn more about making cold process soap
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