This sulfate-free shampoo bar formulation blends super-sudsy shampooing with a rice water rinse in a long-lasting, no-fuss bar form. You can also use this bar as body wash, it doesn’t require any heat to make, and you can have fun with the colour and scent. Let’s dive in!
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The basic gist of this shampoo bar is that it’s a bunch of solid/dry powders that are transformed into a mouldable dough with just the right amount of liquid ingredients. No heating or fancy moulds required (though you can use a fancy mould if you have one!)—just mix it up like you’re making pasta dough, shape the dough into a bar-ish form, and you’re off to the races!
Two solid anionic surfactants form the bulk of the dry phase of this formulation; Sodium Cocoyl Isethionate (SCI) and Sodium Lauryl Sulfoacetate (SLSa). Both are natural, gentle surfactants made from coconut oil. Sodium Cocoyl Isethionate (SCI) contributes a really rich, velvety lather while Sodium Lauryl Sulfoacetate (SLSa) bumps the fluffiness factor. I’m often asked about using just Sodium Cocoyl Isethionate (SCI) in bar formulations; the reason I haven’t done that is because Sodium Cocoyl Isethionate (SCI) is limited at 49.87% in rinse-off applications. So, if you want more solid surfactant than 49.87%, you need to choose something else—like Sodium Lauryl Sulfoacetate (SLSa)!
The final dry ingredient is rice starch. The inspiration for this inclusion came from two places—a very fun hybridizing of ideas! Back in 2020 I found a shampoo bar formulation from Colonial Chemical that contained quite a lot of corn starch, and I was really intrigued (here’s a formulation I shared using corn starch). The corn starch served a role similar to the role of water in a liquid shampoo; it helps dilute the surfactants, making for a milder finished product. Corn starch is kind of invisible in a syndet bar—it doesn’t negatively impact lather, and it won’t melt or soften in hot showers. So, that was place one—a sample formulation and some syndet bars that grew out of that.
Inspiration source #2 was quite a few requests for rice water things for hair + seeing a ton of videos from other YouTube creators about the benefits of rice water for hair. I was really intrigued by the boasted benefits of rice water and its long history of use in Japan and China, but I also knew I was not likely to keep up with something that required a jar of rice water to be maintained and retrieved for every shower. Rice is mostly starch, and that’s the bulk of what will dissolve into water when rice is soaked in water, so I got to thinking… why not skip the soaking step and go straight to the starch? Is rice starch in a shampoo bar exactly the same thing as a rice water rinse? Obviously not, but it’s a lot easier and lower fuss. It’s something I’ll actually use, and that definitely counts for something. I’ve complimented the rice starchy goodness with some hydrolyzed rice protein (one of our wet ingredients) so we get some of the protein from rice as well.
Our wet phase is where you’ll find our last surfactant; amphoteric Cocamidopropyl Betaine. This gentle surfactant helps boost flash foam and make the overall bar milder. I chose camellia seed oil—the oil pressed from the seeds of the plant that gives us tea—to re-fat the bars as I love it for hair and it also has a long history of use in haircare in China and Japan.
A small amount of fragrance scents the bars and lends a wee bit of perfume to the hair. I chose Bramble Berry’s Wildflower Honey fragrance oil, which is apparently inspired by the L’Occitane Honey and Propolis scent (I’m not familiar with it so I couldn’t say). It’s very true to its name, and smells wonderfully of fresh, sweet, floral honey. You could definitely use a different fragrance oil or essential oil if you want, just be sure to work within IFRA guidelines. There’s some more information on this in the Substitutions list at the end of the post 😊 You could leave the bars unscented, too—just replace the fragrance oil with more camellia seed oil.
This bar contains about 11.5% water when it’s freshly made due to the water content in the Cocamidopropyl Betaine and the hydrolyzed rice protein. We’ll want to leave the bar to dry for a few days to allow some of that water to evaporate off, resulting in a very hard bar that’ll last a long time in the shower. I found the bar lost about 3% of its weight in 3–4 days, with diminishing losses after that. These bars are hard enough to use after one day (~1.5% water loss), but if you have the time, I think waiting until day 3 or 4 is worth it for the sweet spot of water lost to time left to age.
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Relevant links & further reading
- Sodium Cocoyl Isethionate (SCI) in the Humblebee & Me Encyclopedia
- Sodium Lauryl Sulfoacetate (SLSa) in the Humblebee & Me Encyclopedia
- Cocamidopropyl Betaine in the Humblebee & Me Encyclopedia
- Hydrolyzed Rice Protein in the Humblebee & Me Encyclopedia
- Camellia Seed Oil in the Humblebee & Me Encyclopedia
- Liquid Germall Plus in the Humblebee & Me Encyclopedia
- Tocopherol (Vitamin E) in the Humblebee & Me Encyclopedia
- How to adjust colour, fragrance oil, and carrier oils
- Other shampoo bar formulations:
Sulfate-Free Shampoo Bar with Rice Starch
4g | 4% hydrolyzed rice protein (USA / Canada)
5g | 5% camellia seed oil
0.4g | 0.4% Wildflower Honey fragrance oil
0.5g | 0.5% Liquid Germall Plus™ (USA / Canada)
0.1g | 0.1% Vitamin E MT-50 (USA / Canada)
Put on your dust mask and weigh the dry surfactants into a bowl. Stir until uniform.
Dissolve the dye in the Cocamidopropyl Betaine. Make a well in the centre of the dry ingredients and add all the wet ingredients.
Put on a pair of nitrile gloves and blend thoroughly with your hands. Once the mixture is uniform, you’ll be left with a stiff, easily-mouldable dough.
If your dough is too sticky, you’ll need to add some starch (arrowroot starch and cornstarch are good choices). This is likely to happen if you used a larger grain Sodium Cocoyl Isethionate (SCI) than I did, as it has less surface area to absorb moisture.
If your dough is too dry, you’ll need to add a few drops of water. This is likely to happen if you used a finer grain Sodium Cocoyl Isethionate (SCI) than I did, as it has more surface area and will absorb more moisture. I used a very finely powdered Sodium Cocoyl Isethionate (SCI), so it is unlikely this will happen—I have never found a more finely powdered Sodium Cocoyl Isethionate (SCI) than this.
Shape the dough into a bar-like lump/disc of your choosing and leave the bar to dry. I’d recommend at least 3–4 days (that’s enough time for the bars to lose ~3% of their weight). If you live somewhere quite humid I’d err on the side of more drying time rather than less as I live somewhere really dry, so that’s what my drying times are based on.
To use, massage the bar into wet hair to work up a lather, and proceed as you would with any other shampoo. This also makes a great body wash if you work it up into a lovely lather with a loofah. Enjoy!
When made as written, the pH of this shampoo is around 5.8, which is great.
Shelf Life & Storage
Because this shampoo bar will regularly come into contact with water, I recommend including a broad-spectrum preservative to ward off microbial growth. In the event you notice any change in colour, scent, or texture, chuck it out and make a fresh batch.
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.
- As I’ve provided this formulation in percentages as well as grams you can easily calculate it to any size using a simple spreadsheet as I’ve explained in this post. As written in grams this recipe will make 100g. You can divide this into as many bars as you want, but I probably wouldn’t try to squeeze more than 3 bars out of a 100g (3.5oz) batch.
- 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.
- The wet/dry balance of this formula is really important; if you change anything (especially any of the three ingredients in the dry phase) you may need to re-develop the formulation to get a workable dough.
- If you’d like to learn more about the surfactants used and compare them to ones you might already have so you can make substitutions, check out this page and read this FAQ.
- I’d recommend Sodium C14-16 Olefin Sulfonate (Bio-Terge® AS-90) instead of the Sodium Lauryl Sulfoacetate (SLSa). Sodium C14-16 Olefin Sulfonate is a solid surfactant; do not confuse it for Sodium (C14-16) alpha olefin sulfonate (Bio-Terge AS40), which is a liquid.
- Remember that the maximum usage level for Sodium Cocoyl Isethionate (SCI) is 50% for rinse-off products, so you cannot use just Sodium Cocoyl Isethionate (SCI) in this formulation.
- You can try a different starch, but you will likely have to re-develop the formulation to get the liquid-to-dry ratio just right.
- You can substitute another liquid oil your hair loves for the camellia seed oil. Rice Bran Oil would fit wonderfully with the theme!
- If you’re like to use a different preservative, please review this FAQ and this chart. This bar is pretty easy to preserve, so I’d feel pretty comfortable using a different preservative assuming it doesn’t have any direct conflicts with the formulation.
- If you’d like to incorporate an essential oil, please read this.
- You can use a different fragrance oil if you want to, just be sure its usage rate for IFRA category 9A formulations is 0.4% (the amount used in this formulation) or higher.
- You can replace hydrolyzed rice protein with a different hydrolyzed protein (oat, baobab, quinoa); just make sure whatever you choose is liquid.
- The dye is optional; I just thought the bars looked rather sterile without it. Replace it with more Cocamidopropyl Betaine if you want to leave it out.
The Cocamidopropyl Betaine, Sodium Lauryl Sulfoacetate (SLSa), hydrolyzed rice protein, Liquid Germall™ Plus, and dye were gifted by YellowBee.
The Wildflower Honey fragrance oil was gifted by Bramble Berry.
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