This creamy Almond Oat Soap came with a rather baffling (and completely unexpected!) mystery! When I sliced it after leaving it to saponify for a day I was delighted to find it was a completely different colour than I expected. Not just a bit darker or lighter (or grey-er, as can happen with saponification), but a totally different colour! One of my awesome patrons solved the mystery—keep reading to find out what happened, and why!

How to Make Almond Oat Soap

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The star oil of this soap is sweet almond oil, in keeping with our theme. You could use a different liquid oil if you wanted to (rice bran oil would be nice), but of course, this will rather remove the “almond” part of this Almond Oat Soap!

I’ve used beef tallow to harden the bar. Lard—just plain ol’ grocery store pastry aisle lard—will also work. To learn more about why I use tallow and lard in my soap even though I’ve been vegetarian for over a decade, please read this post.

Coconut oil amps up the lather; the tub I used in this batch is from Yellow Bee. I’m sure you’ve seen me use packaging from Yellow Bee in the past, and they’ve just started selling ingredients as well! It’s always great to have more shopping options in Canada, and I’ve been happy with the quality of the ingredients I’ve tried so far (this isn’t sponsored, I’m just genuinely excited!). The coconut oil I use when I make soap is always RBD—refined, bleached, and deodorized. While you could use beautiful virgin coconut oil on soap, the RBD stuff is typically far cheaper and works just as well, so I save my lovely fragrant virgin coconut oil for places it can shine! Castor oil rounds out the fat blend, amping up both creamy rich loveliness and bubbles.

The oaty bit of this soap is a pretty hefty dose of straight-up oats I poached from my pantry. I soaked them in the water (measured by weight, the amount that SoapCalc told me to use) overnight, blended that up into an oat-y slurry, and then added the lye to that. The mixture thickens up into a sodium-hydroxide-oat porridge sort of blob, which can be a bit disconcerting, but it works out just fine! The fat mixture is quite slow to trace, especially at room temperature, so you’ll have plenty of time to blend the lye blob into your oils and get the whole thing to a lovely, uniform trace.

You’ll also find a hefty dose of white kaolin clay in this soap because I downright love clay in soap. I find it makes it creamier and richer and honestly, it’s just great and if you haven’t tried it you really should! I also used a bit of brownish-grey rhassoul clay to create a colour contrasting swirl through the soap.

I opted to leave this soap unscented in keeping with the rest of the almond oat formulations I’ve shared lately, but you certainly could include some sort of essential oil or fragrance oil if you wanted to. I think something lavender-y and/or vanilla-y would be really nice!

When I sliced this soap I got quite the surprise; it had turned blueRecord scratch. HUH? I reached out to my patrons with photos and a rough overview of what I’d done, and Greet solved the problem! Apparently, and rather fantastically, steel cut oats can turn a blue-y green when cooked in very alkaline water, and saponification definitely counts as very alkaline cooking conditions. You can learn more here. Very cool! Sadly, the blue didn’t last, fading away completely to the beige I’d expected in less than a day. If you make this soap I would love to hear if yours turns blue as well!

Relevant links & further reading

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Almond Oat Soap

35% sweet almond oil (USA / Canada)
30% beef tallow
30% coconut oil (RBD)
5% castor oil (USA / Canada)

Calculate to 5% superfat with the water at 35% of the fats

Per 500g fats:

  • 10g (0.35oz) rolled oats
  • 30g (1.06oz) white kaolin clay (USA / Canada)

To colour (as needed):

  • Rhassoul clay (I used 5g per 500g oils)

To top (as needed):

  • Rolled oats

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! Please ensure you’re familiar with standard soap making procedures before diving in (click that link if you aren’t!).

The night before: Boil your water, with a bit extra. Put the oats in the jug you’ll be making your lye solution in, and weigh in your just-boiled water (the amount is one of the numbers you’ll get from SoapCalc). Stir, cover, and leave the mixture to soak overnight.

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

Use your immersion blender to blend the soaked oats and water mixture. Once relatively uniform, slowly pour the lye (the precise amount is one of the numbers you’ll get from SoapCalc!) into the oat mixture. Carefully stir to combine. The mixture will heat up quite a lot and will thicken noticeably (this is ok!). Set aside to cool, stirring occasionally over the first 20 minutes or so to ensure all the lye dissolves and none settles out to make a NaOH puck at the bottom of your jug.

While the lye solution cools, weigh the oils into your soaping pot. Melt them together over low heat and then leave them to cool to room temperature.

Prepare your mould—you’ll want a loaf mould for this soap. My mould is wooden, so I line it with parchment paper. Make sure you have one extra container with a pouring spout handy (I use these awesome funnel pitchers). You’ll also want to weigh out the rest of the ingredients (the clays + oats) and have those on hand for when you need them.

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

Blend the kaolin clay into the fats, and then add the oatmeal/lye mixture to the melted fats. You will need to scrape out the porridge-y lye mixture; this is normal! Bring the batter to a thin trace (I found this took a while, 5+ minutes of blending with my immersion blender).

Pour approximately 1/8th of the batter into the secondary pitcher and add the rhassoul clay. Blend to combine, and then pour the rhassoul clay batter into the middle of the pot of batter. Give the whole pot a gentle stir around the edge of the pot, and then pour the batter into your prepared mould. Rap the mould on your work surface to knock out any bubbles. Use a tool of your choice to sculpt the top as desired, and then sprinkle with rolled oats to decorate. Leave, uncovered, to saponify.

After about 24 hours the soap should be firm enough to slice. Unmould it, trim off any dangly bits, and slice away (I recommend positioning the bars so the oat-y topping is the last thing your knife/slicing wire cuts through to avoid dragging oats through your bars, creating gouges). Your soap should be blue on the inside, but that will fade within a day after slicing.

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.
  • 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.
  • Please read the post for suggested alternatives for the almond oil and tallow.
  • I don’t recommend substituting the coconut oil or castor oil; both are quite unique in soaping.
  • For the rhassoul clay: the idea here is to contrast with the base of the soap, so you could use a mica, a different clay, or anything else that is soap-safe and soap stable instead of rhassoul.
  • If you’d like to incorporate an essential oil or fragrance you definitely can—include it in your soap calculator calculations. If you are using a fragrance oil be sure to research it to see how it might impact trace and/or colour as the soap ages.

Gifting Disclosure

The coconut oil was gifted by YellowBee.