This two-layer unscented soap is coloured with clay, and is really beginner-friendly. I designed this soap for my dad as a Father’s Day gift since he prefers unscented products; my Christmassy soaps for 2021 were pretty perfumey, so he put in a special request for something less fragrant. I also designed this soap to use up some oils that needed to be rotated out of my inventory, and I show you how to do that with whatever oils you might need to use up. The partner video for this soap is the most complete soap making video I’ve ever made—I hope you enjoy it 😄 Let’s dive in!

How to Make Rustic Clay Soap

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A big chunk of this fat blend was designed to use up some been-around-awhile liquid oils in my stash that I needed to do something with. Turning older (though not rancid) oils into soap is one of my go-to ways to use them up as soap is very oil-hungry (especially when compared to my usual 100g [3.5oz] batches of lotion that might call for 5g of an oil!). I go into lots of detail on how to do this in the video, but here’s an overview:

  1. Identify some older-but-not-rancid oils you have that need to be used up.
  2. Weigh out what you have and note those weights; this will allow you to develop a fat blend that uses as much of the oils as possible without calling for more than you have.
  3. Calculate the backbone of the formulation (hardening fat [tallow or palm, usually], coconut oil, castor oil) with filler numbers for the liquid oils.
  4. Note the total gram weight of liquid oils, and use your older oils to create a fat blend that adds up to that total weight.
  5. Re-calculate the soap in grams mode to get the proper amount of lye for your fat blend.
  6. Double-check the “Soap Bar Quality” numbers to see where your fat blend falls. You don’t have to stick to the recommended ranges, but they can give you some helpful data. For instance, if the “Hardness” number is low, you might leave the soap in the mould for longer before unmoulding.

My use-’em-up fats was a blend of sweet almond oil (0.93%), sunflower oil (26.67%), and safflower oil (27.4%). That high-ish safflower oil content ending up pushing up the iodine value for these bars, meaning they probably won’t last as long as a lower iodine bar and will be on the softer side. I’m not super concerned about this for a one-off, not particularly large batch of soap, but I wouldn’t recommend going out of your way to replicate my fat blend. I usually use oils like Olive Oil and Rice Bran Oil for the liquidy bits of my soapy fat blends, and they’ve worked very well in my soaps over the years.

The colour for this soap comes from two clays. The entire batch contains a good dose of white kaolin clay for both a creamy appearance and creamy lather. I’ve used a bit of French Green Clay to colour the top layer of the soap; if you wanted that layer to be a different colour you could use a different clay, like French pink or French yellow. You could also use a mica instead, though you won’t need as much.

This soap batter traced easily, thickening up to sculpt-able levels by the time I got the green layer scooped on and spread out. It was soft but sliceable after about 36 hours in the mould, though I’d recommend slicing it with a wire rather than a knife—my knife slices looked really sticky. My wire slicer is a cheese slicer; I often see these at thrift shops, so keep an eye out for a second-hand one if you’re interested in getting one of your own.

These bars have a really lovely creamy, low lather that’s quite decadent. Enjoy!

Relevant links & further reading

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Rustic Clay Soap

55% liquid oils (read the pre-amble for details)
20% beef tallow
20% coconut oil (RBD)
5% castor oil (USA / Canada)

Per 500g fats:

Calculate to 5% superfat with “Water as % of Oils” set to 30%

Kick things off by calculating out your recipe for the amount of soap you’re making to get the finite amounts of the fats, lye, and water. Unsure about how to use SoapCalc? I made a video to walk you through it! The video tutorial for this soap also features a lot of details on how to calculate the soap and how to make it from start to finish.

Put on your safety gear; gloves + eye protection of course, and an apron is also a good idea.

Prepare your mould—I used the loaf mould my dad made me for this soap, but you could use a cavity mould if you prefer.

Melt your oils together in your soaping pot and let your oils cool to slightly warmer than room temperature. Mix up your lye water and let that cool to about room temperature (I always use ice for part of your water to speed up the cooling process).

Once the lye solution and the melted fats have cooled to slightly warmer than room temperature, you’re ready to get started!

Blend the kaolin clay into the fats, and stir the sodium lactate into the lye water. Gently pour the lye mixture to the melted fats. Bring the batter to a thin trace. Once you’ve reached a thin trace, pour about 1/4–1/3 of the batter into a second container/pot, and blend the French green clay into that part of the batter.

That’s it for the batter! Pour the kaolin clay part of the batter into the loaf mould, and then knock the mold on your countertop to even it out and work out some of the bubbles.

Gently spoon the green batter on top of the uncoloured batter, smooth, and sculpt the top as desired. Once you’ve sculpted the top (I did a bit of a mohawk with my spatula), leave it to saponify.

After about 36 hours the soap should be firm enough to slice (though depending on your mould you may want to freeze it first—I used a silicone mould and froze it to prevent denting, but I don’t think you’d need to if you used a brittle mold that you can deconstruct to remove the loaf). Unmould it, trim off any dangly bits, and slice away.

Leave the bars to age (aka dry) for 3–4 weeks before using. Enjoy!

Shelf Life & Storage

Because bar soap has a low water content, high pH, and very high anionic surfactant content (soap is anionic surfactant), it is self-preserving. These bars should last years if allowed to dry between uses. If you start to notice orange spots developing on the surface of the soap, throw it away.


As always, be aware that making substitutions will change the final product. While these swaps won’t break the recipe, you will get a different final product than I did.

  • Before you can make this soap you’ll need to calculate it out with a soap calculator to get finite amounts for the fats, water, lye, and add-ins. I have a tutorial on how to do this here. You can definitely use a different fat blend; I cover how to do this in the partner video!
  • To learn more about the ingredients used in this formulation, including why they’re included and what you can substitute them with, please visit the Humblebee & Me Encyclopedia. It doesn’t have everything in it yet, but there’s lots of good information there! If I have not given a specific substitution suggestion in this list please look up the ingredient in the encyclopedia before asking.
  • You could use a different soft, coloured clay instead of French green clay for a different colour (just tread carefully with more pigmented clays like the Australian clays… soap that bleeds red is a bit terrifying in the shower!).

Gifting Disclosure

The coconut oil was gifted by YellowBee.
The safflower oil was gifted by Essential Wholesale.
Links to Amazon are affiliate links.