Sodium Cocoyl Isethionate (SCI)

What is it? A solid, gentle anionic surfactant made from coconut oil.
INCI Sodium Cocoyl Isethionate
Appearance You can buy SCI as a fine powder, a lumpy powder, chips, or noodles/tiny sticks.
Usage rate The CIR has tested it at up to 49.87% in rinse-off applications and 17% in leave-on applications.
Texture It depends on what you buy (see “appearance”).
Scent Characteristically soapy/detergent-y.
Active Surfactant Matter ~84% (always double check with your supplier)
pH 4.5– 6.5 (10% Solution)
Charge Anionic
Solubility Water
Why do we use it in recipes? It offers beautiful, gentle “lace glove” lather to our products. It’s also naturally acidic, so it helps our end products have a skin-friendly pH with less (or no) adjusting.
Do you need it? If you’re only going to buy one solid, anionic surfactant, I’d recommend this one.
Strengths Wonderful, gentle lather.
Weaknesses The larger shapes can be a pain to melt down.
Alternatives & Substitutions As a bare minimum you’ll need a different solid anionic surfactant. You’ll also need to watch the active surfactant matter (you may need to use a different quantity of the new surfactant to get the same ASM level in the end product) and the pH of the final product. Keep in mind that most solid anionic surfactants are not as gentle as SCI. Two options to consider would be SLSa and Bio-Terge AS90.
How to Work with It Wear a dust mask! Inhaling airborne powdered surfactants is unbelievably unpleasant.

Depending on the form you have and the format of the end product the SCI may need to be melted first. A liquid end product will require the SCI to be melted—I’d recommend combining it with the liquid amphoteric surfactant that is likely also present in the recipe and heating the two together in a water bath until you have a uniform paste. If you are working with a large amount you can speed things along with an immersion blender—the low water content means it won’t lather up, but you’ll get a smooth paste very quickly! You can also speed up melting times by running your SCI through a coffee grinder before combining it with the liquid amphoteric surfactant—just be sure you are wearing your dust mask!

If you’re making a solid product you might not need to melt the SCI, depending on the format. If you’ve got large flakes you’ll probably want to, but the little noodles look really cool in shampoo bars as-is, and the fine powder is very flexible!

Storage & Shelf Life Stored somewhere cool, dark, and dry, SCI should last for two years.
Tips, Tricks, and Quirks I like to pre-prepare a paste of SCI and Cocamidopropyl Betaine (2 parts SCI to 3 parts Cocamidopropyl Betaine) and store it in the fridge. That way I can skip the melting step when I need melted SCI!

Watch for SCI that has been blended with stearic acid (INCI will list stearic acid); that isn’t the same product.

Recommended starter amount 250g (0.5lb)
Where to Buy it  Buy it from an online DIY ingredient supplier or Amazon.

Want to compare different surfactants?

Check out my super useful surfactants table!

 

Some Recipes that Use Sodium Cocoyl Isethionate

Skills

Posted on

November 22, 2018

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