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Grapefruit Ginger Cold Process Salt Bar Soap Recipe

I have an interest in handmade bath and body products, so I am continually experimenting with new soap-making recipes and techniques.


I’m a member of a Facebook group with a bunch of other soap makers, and when I first joined the group as a beginner, everyone was in the middle of a salt bar soap exchange. Salt bar? What the heck is that? So I read up on it a bit and decided that I must make some of these myself!

What is a Salt Bar, Anyway?

Simply, it’s bar of soap that has sea salt added to it. The reason people do it is for the properties the salt adds to the soap. Sea salt is full of minerals, and just as taking a salt bath can help to soothe pain and inflammation, it would seem that washing with a salt bar may have similar positive effects. I don’t know if I buy all of that, since you would soak in a salt bath for about 20 minutes or so, while soap is just washed away. However, the claim is also made that washing with a salt bar can regenerate and hydrate the skin, while removing toxins and impurities. I think this is more easily believed, since the salt is a bit exfoliating.

I learned a few things from my first couple of batches and I wouldn’t make that first recipe again, for a few reasons – mainly because my superfat was too low. There is room for experimentation with these. You can use up to 100% coconut oil in a salt bar, and the same goes for the amount of salt you use – I prefer half my oil amount, but you can use up to 100% of your batter amount. The reason the coconut oil is so high is that the salt reduces lather and coconut oil will still lather in salt water; and the reason the superfat is so high is because the coconut oil can be drying. It’s all about balance.

The recipe below is a pretty standard salt bar recipe, although I've tweaked it to lower the coconut oil percentage. Feel free to tweak it to your preference – but always run it through a soap calculator afterward to make sure your lye amount is correct.

Grapefruit Ginger Salt Bar Soap Recipe

Yield: 1 lb

You’ll want to use a mold that has individual cavities (or a slab mold with dividers), because salt bars harden very quickly and once your soap is hard, you can’t cut it into bars without them crumbling all over the place.

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  • 11.2 ounces coconut oil, 70%
  • 4 ounces olive oil, 25%
  • .8 ounces castor oil, 5%
  • 2.15 ounces lye (sodium hydroxide), this makes a 20% superfat
  • 6.05 ounces water
  • .65 ounces grapefruit essential oil
  • .35 ounces ginger essential oil
  • 8 ounces fine grain sea salt, not Epsom salt or dead sea salt
  • 1 teaspoon pink colorant, mica or clay


  1. First, melt your coconut oil in a stainless steel pot (never use aluminum or you'll ruin the pot and your soap) and then add the liquid oils. Add your colorant to the melted oils and stir.
  2. Measure out your water and lye in separate containers. Then, wearing rubber gloves, protective eyewear, and a ventilator mask, slowly add your lye to the water, stirring constantly. Never add the water to the lye, you should always add the lye to the water.
  3. Allow the lye water and oils to cool to around room temperature (70 - 80 degrees). There is no need for both to be the exact same temperature. Put your goggles and gloves back on, and slowly add your lye water to your oils, mixing with an immersion blender. You know you are done mixing when the soap batter reaches "trace." Trace means that if you take the blender out, any droplets that fall off of it will sit on top of the batter, instead of disappearing back into it.
  4. Stir your fragrance into the batter with a silicone spatula.
  5. Stir your sea salt into the batter, a little at a time. Keep stirring until the batter is thick enough to suspend the salt, without it sinking to the bottom.
  6. Place your cavity mold onto a cookie sheet or another surface that can be lifted. Pour the soap into your cavity molds and tap the cookie sheet on the counter a few times to eliminate air bubbles and smooth out the tops of the bars.
  7. Leave the soap harden for 12 to 24 hours. If the bars are sticking to the mold, put it in the freezer for 30 minutes and try again to remove them. At this point, your bars need to sit in a dry, well-ventilated area for 4-6 weeks to cure. It is not recommended to use the soap before this time.

Salt Bar Soap Variations

Cucumber & Aloe – I used about 35% aloe vera juice and 65% pureed cucumber in place of my lye water and left the soap unscented. The cucumber scent came through very faintly at first in the finished bars, but it faded over time. I would use a cucumber and aloe fragrance oil next time.

Salt Bars made with Glycerin Soap (a melt & pour version).

Soleseife Soap – I learned that you could make a different kind of salt bar by dissolving the salt in your water before adding lye to it. I have tried this a couple of times, and have posted a recipe for soleseife soap.

Final Thoughts on Salt Bars

Most people make their salt bars with 100% coconut oil, but even with the high superfat, this dries my skin. I didn’t think salt bars had to be 100% coconut oil and I intended to prove it with this recipe. It came out just fine using 70%. I wonder how low I could go with that percentage and still have lather. An experiment for another day!

© 2018 Katie Adams

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