The experiments: Making cold process turmeric soap

Why Turmeric?

If you want to learn about the benefits of Turmeric (otherwise known as Curcuma longa), you need not go very far! The internet is full of articles boasting its health benefits, either from ingesting it or applying it topically to the skin. However, my initial interest in turmeric was not for its health benefits, but rather its effectiveness as a natural colorant for my soap. I was vaguely aware that it was also good for the skin, but that was not why I decided to include it in my soap — Turmeric was easy: I had it around the house, and there were already soapers online that showed turmeric in soap would produce nice results as a colorant. Shades range from light orange to dark, burnt orange (see the article posted by Bramble berry where they test the color produced using different methods of adding turmeric to soap).

The Recipe (%)

I chose to add turmeric at trace since that method appeared to give a more vibrant color. I used SoapCal to determine the amount of lye I would need for 7% superfat, and kept the default for water as percent of oils (38%). The recipe I put together was composed of:

Oil / ButterPercentage
Olive Oil45%
Coconut Oil40%
Shea Butter10%
Castor Oil5%
Superfat7%
AdditivePercentage
Spearmint Essential Oil2% or 0.5 Oz per pound
Tea Tree Essential Oil1% or 0.25 Oz per pound
Ground Turmeric1% or 0.25 Oz per pound

Since I was going for a medium shade, I decided to add 1 tsp of ground Turmeric per pound in the recipe. Soapcalc estimated a final weight of ~55 ounces, giving ~3.5 lbs total. I mixed 3.5 tsp of turmeric with 3.5 Tbsp of the olive oil and added at trace.

After 24 Hours: Unmolding

The batch fit into my 10″x2.75″x3″-inch loaf mold plus two silicone muffin liners (which I only use for soaps or balms). I let the soap harden for 24 hours and then took the soap out of the molds and sliced up the loaf into 10 pieces of soap. Assuming 12% water loss, this should give me 4 oz bars of soap, while the muffin soaps will be around 2.5 oz. I measured the total weight of the soap at this 24 hour mark, and it was at just about 55 oz. At this stage the soap was still very sticky, and I would recommend waiting until 48 hours to slice up next time. The color appeared more muted than at trace, and reminded me a bit of cooked pumpkin pie. There also appeared to be red speckles where the turmeric clumped slightly, which gave it a nice textured look.

Just after unmolding and cutting.

This soap will cure for a total of 4-6 weeks.

On Temperature

I noticed the soap developed a layer of soda ash within the first week, since I had not been working at high temperatures when making the soap, but this was easily remedied by running the soap under water (while wearing gloves to prevent fingerprints):

Soda ash on the soap before cleaning.

The texture of the soap after cleaning.

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