This DIY liquid castile soap recipe is super versatile. You can use it as is, or jazz it up with your favorite essential oils or fragrance oil blends. It’s gentle, nourishing, and great for mother and baby, or anyone with sensitive skin.
When someone asked about liquid castile soap, the first thing that popped into my head was how gentle and nourishing the cold process castile soap I made was. It’s great for mother and baby, or anyone with sensitive skin. It provides gentle cleansing that leaves skin feeling supple and super soft!
Watch How To Make Liquid Castile Soap
Super Versatile Liquid Castile Soap Recipe
Liquid castile soap is super versatile, too. You can use it as is or jazz it up with your favorite essential oils or fragrance oil blends.
I like to add a vibrant color as well. You can also throw in other moisturizing additions such as glycerine, d-panthenol, or even some oat proteins to give it an extra punch of skin-loving goodness.
Have a look at some of my recipes using a soap base here on my blog for a few ideas on how to take a liquid soap and really make it your own.
Coconut Oil? But Why?
I’ve added coconut oil to this recipe. I know it’s a sin to put anything other than olive oil in a castile soap recipe, but the coconut gives us a little extra lather and will lift the color of the finished product. This is important if you want to use a liquid soap dye.
If you want to make pure castile soap with just olive oil, that’s totally ok, just run it through our soap calculator first to make sure you are adding the right amount of potassium hydroxide and distilled water to make a good paste.
Time-Consuming, But Totally Worth It
Making traditional lye-based liquid soap can be a bit time-consuming. Let’s face it, for a decent sized batch you are looking around three days from start to finish.
Don’t get me wrong, it’s not exactly grueling work, nor is it particularly hard to do. But you’ll spend the first day sitting around waiting for the soap to cook, coming back to stir every now and then.
In the next few days, you’ll have your freedom back, as you’re just waiting for the paste to dissolve and it can pretty much sit happily on its own. Confused? Don’t worry. All will be made clear in my recipe card below.
Because it’s so time-consuming, I find it easier to cook an extra-large batch of soap paste in one go, then store a good two-thirds of it in the fridge until needed. It will last around a year if it’s sealed in an airtight container or zip lock bag, and it’s so handy to have around especially in the holiday season.
So if you want to learn how to make my liquid castile soap, take a look at the recipe below. Its basically the same process as in my original liquid soap making tutorial, but with different oils. Don’t forget to watch the video as well. I always think videos are great learning companions for any written recipe.
The recipe shows almost 2 days to make this soap, but remember that most of the time is not really active, it is spent waiting for the processes to complete.
Stage 1: Making The Soap Paste
The soap paste in this recipe will take around 6 hours to cook depending on the heat setting on your crockpot.
Stage 2: Dilution Stage
The dilution time usually takes around 24 hours, you don’t need to do anything to it during in this stage, however, it’s almost impossible not to give it a quick stir now and again.
Liquid Castile Soap Recipe For Sensitive Skin
- Spoon or Spatula
- Melt the coconut oil in the microwave and pour it into the crockpot. Add the olive oil and turn the crockpot on to a low setting.
- Place 750g of Distilled water into a sturdy, plastic container. Wearing PPE, (gloves, goggles, and facemask) and working in a well-ventilated area, weigh the Potassium hydroxide. You will want to keep your PPE on while working directly with lye and raw soap batter. I will let you know when you can take it off.Add the potassium hydroxide to the water and stir it well. As you add the lye to the water you may hear it rumble or hiss, this is quite normal. Set aside until It has fully dissolved and has clarified.
- Once the lye solution has clarified, and your coconut oil has dissolved, you can combine them in the crockpot. You should always pour your lye into your oil, and do so carefully to avoid splashing.
- Give the stick blender a quick blitz to remove any trapped air bubbles before placing it into the oil/lye mixture. Keep the blender on low to avoid splashing, blending the batter for a couple of minutes at a time. This gives both your batter and your stick blender a short rest. While you can use your stick blender continuously, you will risk burning it out.
- Continue with the blending until the batter reaches trace. For anyone who isn't familiar with this term, its where you can leave a noticeable trace on the surface of the batter when you let the soap trickle from the stick blender. As you blend, you may notice that the batter tries to separate at times, don’t panic just keep blending until it reaches trace.
- Once the batter has reached trace, continue blending, using the same technique, until the batter begins to resemble mash potato. This is essentially a very heavy trace.
- It's now time to pop the lid on and let the batter cook into a nice thick paste. This can take anywhere from 4-7 hours and will need stirring every 20 to 30 minutes. You will notice it going through various stages during this time. First a thick mash potato, then apple sauce, and finally a golden translucent paste similar to vaseline, although not in color.
- When the paste reaches its golden translucent stage, I prefer to turn off the crockpot and leave it to rest overnight. In the morning, I decide whether to dilute all the paste or store some or all of it in the refrigerator for another time. The paste will last for a year if it has been sealed in a zip lock bag or airtight container.
- If you decide to dilute it all now, pour 2500g of hot distilled water over the soap paste. Stir well and then turn the crockpot on to a low setting for a couple of hours. After, turn your crockpot off completely. While you can keep it on for longer, if you are going out or going to bed, don’t be tempted to leave it on. The soap paste will still dissolve just fine with the crockpot switched off. If you have decided not to dilute all your paste at once, weigh whatever amount of paste you wish to use, put it back into the crockpot and add double the amount of water to the soap. It’s basically a ratio of 1:2.
- When the soap is fully diluted you need to test the PH level with a universal indicator strip. You are looking for a range between 9 and 6. If it is too high it can be lowered with a little citric acid. Make up a solution of 1 part citric acid to 4 parts warm distilled or pre-boiled water. Stir a little into the soap, give it a few minutes then test it again.
- If you are not adding any essential oils or color to the soap then it is now ready to be transferred to bottles. The finished soap will last 6 months without a preservative and 18 months with. If you want to add a preservative make sure you choose one that’s tolerant of a high PH such as plantaserve P (Saligurd PCG) and use it at around 1%, stirred into the soap prior to bottling.
- Adding scent and color is a personal choice that can change the consistency of the soap. I've noticed that my fragrance oils seem to make it thicker, so I add a little distilled water to thin it out again. Essential oils (especially citrus ones) can actually make it thinner. Adding some gum that’s been dissolved in glycerine, or salt that’s been dissolved in a little water will help to thicken it. As this is a wash-off product its safe to use up to 2% of your essential or fragrance oils.I find liquid soap dye to be better in this recipe than other types of soap dye. It won’t fade with time like mica does. I use one that’s food safe and vibrant so I only need a couple of drops.
Soap Calculator & Formulation Guide
Select your chosen oils, along with the weight or percentage. The lye soap calculator will then show the total weight of lye and water required. The result can be instantly adjusted by changing your preferred superfatting level or water/lye ratio.