Kombucha Soap Recipe
This recipe is a terrific way to use up extra homemade kombucha. (If you’re not sure what the heck “kombucha” is or how you’d go about making it, check out my friend Kristi’s post, HERE, to learn all about it.)
Besides its possible health benefits, kombucha (a fermented tea drink) is reportedly great for your skin too. I’ve been using homemade infused kombucha as a facial toner for a while and do love it!
Something I’ve noticed about kombucha soap is that it has that faint and slightly medicinal smell, that you also get when you add witch hazel to soap. I’m not a huge fan of that scent, so like to add essential oils to brighten it up. Lemongrass, lavender or peppermint are three of my favorites that I buy through Bramble Berry. (I’ve found that they have the best prices on quality essential oils that actually stick around in soap.)
Try adding around 1 to 2 tablespoons (15 to 30 ml) to lightly scent a batch of soap this size. I usually use the Bramble Berry fragrance calculator (found HERE) to get an idea of how much essential oil is needed in my recipes.
This website contains affiliate links to Bramble Berry, Mountain Rose Herbs and Amazon. If you click on one and make a purchase, I earn a small commission for sending a customer their way. This costs you nothing extra, but does help to support my site and lets me keep doing what I do. Thank you!
To create this recipe, I started with a base of Olive Oil, a basic soap making oil with emollient properties, plus Coconut Oil, another soap making staple that adds great lather and hardness. If you’re allergic to coconut oil, try using babassu oil instead.
I then added some Rice Bran Oil, which is rich in vitamin E and also a good replacement for some of the olive oil in a recipe, Sunflower Oil, high in fatty acids and provides a stable, conditioning lather and Cocoa Butter, which adds extra hardness to soap – a characteristic that’s especially useful when making palm-free recipes. Cocoa butter will influence the scent of your finished soap, so I like to use the deodorized form in this recipe.
For the majority of soap recipes on this site (and in my ebook – Natural Soap Making), I use a homemade wooden loaf mold (inner dimensions are 8″ x 3.5″ x 3.5″), this 12 Cavity Rectangle Silicone Mold (filling around nine of the twelve cavities) or this silicone column mold for round soaps (if using this one, reduce the liquid by around 1 ounce so it will fit in the mold and firm up faster). You could also try using a sturdy shoe box or empty milk carton, lined with an inexpensive, unscented trash bag, to make a disposable mold.
I use and recommend Essential Depot’s food grade lye HERE (from Amazon).
If you’ve never made soap before, research the process thoroughly before proceeding. An overview of basic directions can be found in my Soapmaking 101 post. For more in-depth information including tips on coloring soap naturally, how to read a lye calculator, plus 25 of my favorite palm-free recipes, check out my ebook: Natural Soap Making: Cold Process Basics & Recipes.
Kombucha Soap Recipe
Superfat is 6%. All measurements are by weight. You must use a digital scale to make soap.
- 5 oz (141 g) chilled kombucha
- 5 oz (141 g) chilled water
- 14 oz (397 g) olive oil
- 7 oz (198 g) coconut oil
- 4 oz (113 g) rice bran oil (or more olive oil)
- 3 oz (85 g) sunflower oil
- 2 oz (57 g) cocoa butter
- 4.14 oz (117 g) lye
Step 1: Weigh out the chilled kombucha and water into a heat proof plastic or stainless steel pitcher or container.
Step 2: Wearing safety goggles, gloves and long sleeves, weigh out the lye and pour it into the pitcher of kombucha and water. Stir well to make sure the lye is fully dissolved. It will heat up quickly and give off strong fumes that you should avoid breathing in directly. I like to do this step in my kitchen sink, in order to contain any spills or splashes. Set the solution aside in a safe place, out of the reach of children and pets, and let cool for about 30 to 40 minutes. The temperature should drop to around 100 to 110°F (38 to 43°C) during that time.
Step 3: Weigh the coconut oil and cocoa butter into a small saucepan or double boiler. Melt gently over low heat, keeping a close eye on it. Weigh the other oils into your soap making pot or container and then pour the melted oils into there too. The melted oils should bring the temperature up to around 90 to 100°F (32 to 38°C), though you don’t have to get too hung up on trying to make the temperatures match.
Step 4: Now, you’re ready to mix! Working carefully and still with gloves, goggles and long sleeves on, pour the lye solution into the oils. Stir by hand for around 30 seconds then begin mixing with an immersion (stick) blender. Do not use a hand mixer – you want a stick blender that looks like THIS.
Step 5: Blend for around 30 to 40 seconds, then hand stir with the motor off for 30 to 40 seconds. Alternate until trace is reached. “Trace” means that your soap batter has gotten thick enough so that when you drizzle some of it across the surface of itself, it leaves an imprint or “tracing” before sinking back in.
Step 6: After trace is reached, you can add in any extras that you’d like, such as essential oil, honey, oatmeal and so forth.
Step 7: Pour the soap into the prepared mold and cover with a sheet of wax paper, then the mold’s top or a piece of cardboard. Insulate the mold with a towel or small quilt, but peek every so often to make sure that the soap isn’t overheating. It will darken in spots and take on a gel-like appearance at some points (that’s all normal as it goes through “gel phase”), but if you see a crack developing down the middle, it’s getting too hot and should be uncovered.
Step 8: Allow the soap to stay in the mold for at least 24 to 48 hours. Remove from the mold and slice into bars. This recipe yields around 8 bars of soap. Let the soap cure for at least 4 weeks before use.
Hot Process Variation:
To make this soap in your crock-pot, follow steps 1 through 5, as written. After trace, place the soap batter in a slow cooker, turned to low heat. Cook for 1 hour, checking and stirring every 15 minutes. The soap will darken and go through many phase changes as it cooks. After the cook time, you can stir in essential oil or any extras that you’d like. Spoon the hot, cooked soap into a mold and allow it to firm up for around 24 hours. Slice into bars and you’re done! You can use hot process soap right away, but it still benefits from a few weeks of cure time.
If you have any questions I didn’t cover, feel free to leave them in the comments below. Because of pesky spammers, I have to keep several layers of spam filters in place and unfortunately some legitimate comments get lost in the process. If your comment doesn’t show up in a week or so (it sometimes takes me that long to get to them), then try again with a different email address. I try to answer every single one that I see. Thanks! :)
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