When someone asked about a DIY liquid castile soap recipe, the first thing that popped into my head was how gentle and nourishing those lovely solid bars of DIY castile soap were.
Castile soap is great for mother and baby, or anyone with sensitive skin. It provides gentle cleansing that leaves skin feeling supple and super soft! The recipe below is super versatile, you can use it as is, or jazz it up with your favorite essential oils or fragrance oil blends.
Super Versatile Liquid Castile Soap Recipe
A Liquid castile soap recipe 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.
Notes:
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.
How To Make Liquid Castile Soap For Sensitive Skin
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Equipment
- Mixing Bowl (Glass, Aluminium or PET)
- Spoon or Spatula
Ingredients
- 645 grams Olive Oil
- 105 grams Coconut Oil
- 750 grams Distilled Water
- 151 grams Potassium Hydroxide KOH
- 2500 grams Distilled Water (2.5 ltrs)
- Preservative (1%, high PH tolerence)
Video
Instructions
- 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.105 grams Coconut Oil, 645 grams Olive Oil
- 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.750 grams Distilled Water, 151 grams Potassium Hydroxide KOH
- 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 1:2.2500 grams Distilled Water
- 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.Preservative
- 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.
Notes
How To Make Castile Soap At Home
Here’s how to make Castile soap, it’s absolutely one of my favorites. It’s simultaneously one of the most inexpensive soap recipes you can make (making it a great beginner soap), but also the most gentle of cleansers at the same time.
Soap Calculator & Formulation Guide
Select your chosen oils, along with the weight or percentage. The 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.
Hi there! Thank you so much for this fabulous recipe! I am in the process of making the liquid soap now and I wanted to ask; about how long does it typically take to come to trace after you add the lye solution? I’ve been blending off and on for over ten minutes and it’s not really getting any thicker. Is this normal?
Hi Savannah,
Yes, sometimes trace can take a little while, as long as 20-30 minutes. If you’re still not reaching trace at the point, I would double check your measurements to make sure you’re using the right ratio of lye to water. Otherwise, you could use some ingredients that help to expedite trace, but this is a very tricky thing to do and can bring out ricing (e.g. a floral fragrance oil), so I would just try to be as patient as possible (it’s hard sometimes, I totally understand). Hope this helps and happy soaping!
Is it possible to halve this recipe for liquid soap or would that potentially cause problems? I’m so excited to get started!
Hi Holly,
Yes it is! As long as the formula is the same, you can scale up and down as you like. 😀
Hi, cab this be used for baby wash or face wash?
Hi Lee,
You can use it for both. You could also use it as hand wash. It’s pretty versatile, because it’s great for sensitive skin! 😀
Can you tell me why my soap is not diluting? As it cools it is starts looking like paste again.
Hi Wendy,
Not sure why this is happening, perhaps you’re not adding enough water? This process can take quite some time before it’s properly diluted.
Hi Angela
This might be a silly question, but can you still use your crockpot for food prep after using it for soap making? I’m new to this, so just want to make sure.
I’m excited about trying to make my own soap.
Thank you
Hi Wilhelmina,
This is actually a contentious issue, and while I have used the same for soap and food I can’t in good conscience recommend it. lye based liquid soap SAPs so so fast, which means all the lye is gone quickly too. However, as you’re new to liquid soapmaking, it might be best to separate your food prep equipment from your soapmaking equipment. If a mistake in measurements is made, and your soap becomes lye heavy, it’s possible for some of that lye to remain after cleaning and work it’s way into your lovely crockpot meals. So It’s a risk I wouldn’t recommend taking right now. Hope this helps!
Should this soap cure? I can’t find that part. Thank you so much! Love your page!
Hi Wendy,
Not at all, that’s the beauty of liquid soap! Once you’ve bottled it’s ready to use immediately.
Thank you!
hello my soap it is transformed into jello why?
Hi Magalie,
Jello? How odd! I mean it does kind of look a little gelatinous while it is still a paste, but after you dilute it with enough water it should be a runny liquid. Have you checked your measurements were accurate?
Try adding some more water, hopefully that will solve the issue.
Thanks it helps a lot
My liquid castille is completely clear but has a brown hue to it. Is there a way to remove the brown from it or change something in the next batch? I followed another recipe which had me leave the crock on low for 10 hours as it was diluting…could this b why it’s a clear brownish color?
It’s quite normal for your castile soap to have a slight yellow hue to it. If this is what you mean, I wouldn’t worry so much. You can use a variety of different liquid soap dyes to get a more desirable color.
As for leaving the crockpot on for 10 hours, it’s really not that necessary. A couple of hours will do the trick. Although personally, I can’t see this being the reason for the discoloration of your soap.
I would say try following my recipe next time, and if its the same then I would look for a different liquid soap recipe. You could also try making liquid soap with surfactants. I do this all the time, and it’s possible to get a pure, colorless, transparent soap this way quite easily.
Olive oil comes in different shades. I’ve noticed that since I started. Does that change the hue of the finished product
Hi Wendy,
Yes it does a little. However, you’ll find that it still remains relatively beige. I haven’t noticed a huge difference in all my years of soaping. Hope this helps!
Thank you!
Hi Angela!
I am happy and grateful for this recipe and great education in this writing! I read so many articles and watch many tutorials but none of them would be as detailed as this, thank you!
I made my liquid soap and it happens to have a white layer on top of it, I try to read everyday to see what I did wrong and I can’t get any answers for that,
Kindly please help me understand what is it that I did wrong!
Thank you so much and many greetings from Africa!
Hi Gertrude,
I’m so sorry to hear you’re having problems with this soap. Can I ask, are you following the ingredients exactly, including using distilled water? The only two things I can think of it being are either left over unsaponifiables (stuff that won’t SAP into soap) or perhaps chalky local water. Are you trying to use a cosmetic butter? If so, that’s probably the culprit here.
Other than that, I can’t say for sure what it would be as I’ve not had this problem. You could try just skimming off the top, white layer?
Keep me updated on how you get on?
Hi, thanks for the recipe! My mum loves Dr. Bronner’s soap so we were excited to try and make our own but a dilution of 1:2 has come out way too thin 🙁 our soap is also cloudy, where did we go wrong? Will salt help thicken it up even though it’s cooled down now?
Hi Claudes,
Yes, the salt will most definitely thicken it up. This is very common and nothing to worry about. Sometimes additional ingredients such as essential oils and fragrance oils can also alter the viscosity drastically. So if you are intending to add a fragrance do that before trying the salt.
Traditional soap making processes are also very unforgiving and at times very temperamental. But the salt will help for sure. Follow the recommendations I’ve made for thickening your soap with salt above on the post.
As for the cloudiness, this can happen. Mine is sometimes cloudy as well. This is often because of the natural glycerine content of your soap. We can get this problem in solid soap bars sometimes as well, in the form of glycerine veins/marbling. It’s totally still good to use and can look quite beautiful with the addition of some soap dye. Just be sure to check the PH of your liquid soap to make sure it’s safe.
Try not to get disheartened by this. In the soap-making industry, they have lots of different technical equipment to ensure things like this don’t happen (usually it’s a rapid fluctuation in temperature during the cooking phase, or overcooking of your soap paste). But we’re home soap makers, it’s difficult to replicate this in our kitchens. So cut yourself some slack, making soap is hard, you did a good job.
Besides, cloudy liquid soap that is packed full of skin-loving ingredients is still a better alternative to the suspiciously clear, store-bought soap that has a ton of different ingredients that can irritate your skin.
Anyway, let me know how you get on thickening your soap, and good luck with your next soap! 😀
Hi. Thank you for this recipe!
Should the soap be a certain temperature when adding the fragrance?
Also, will the fragrance survive the wash/dry cycle, scenting the finished clothing/linens etc. So far, after much trial and error I have been unsuccessful. Any recommendation (preferably natural) would be most appreciated! Thank you.
Hi Jerri
I always add my fragrance at the end after the soap has cooled, it’s much easier to handle then and make adjustments as mentioned in the post.
I haven’t tried using this liquid soap to wash clothes with, so I can’t comment on how the fragrance holds up through a wash. Have you been using this specific recipe for clothing, or another? Apart from the fragrance issue how did you get on, its something I would like to try.