This pH sensitive dye turns pink in handmade soap

🟢Get the soap formulator’s workbook here →
https://www.tellervo.fi/shop/p/the-so...

In this soap making video I show you how to use himalayan rhubarb (rheum emodi/rheum australe) root powder to color handmade soap pink.

Himalayan rhubarb is an ornamental rhubarb variety that grows wild in the Himalayan mountains. The root of the plant is traditionally used as a dye and it yields a deep, golden yellow color when dyeing fibers. In an alkaline environment, like soap, the color morphs into a deep pink or red.

Rhubarb root powder I could find on amazon: https://amzn.to/2URYHtz (This is the rheum palmatum variety, but it should work too)

I purchased my rhubarb root powder from https://www.wonkyweaver.com/

I created this soap with help from this blog post by lovely greens:
https://lovelygreens.com/himalayan-rh...

Recipe:

Recipe calculated with: https://soapee.com/calculator

Please wear proper safety equipment when making soap.

250 g olive oil infused with himalayan rhubarb powder (50 %)
25 g castor oil (5%)
150 g coconut oil (30%)
75 g shea butter (15%)

10 g citric acid + 2 tbsp distilled water

76.4 g sodium hydroxide (70.4 g if not using citric acid)

120 g distilled water (frozen)

(37% lye concentration, 5% superfat)

10 ml fragrance or essential oil for a light scent (I used ‘enchantment’ by gracefruit)

Cure the soap for 4-6 weeks before using on your skin.

○ Citric acid information

When citric acid and sodium hydroxide lye (NaOH) are combined, sodium citrate is created. Sodium citrate works as a chelator in soap.

A chelator traps metal ions such as calcium and magnesium that can be found in tap water.

These metal contaminants can cause rancidity and soap scum in handmade soap.

A chelator binds to these metals so that they can’t bind to the soap molecules. This way the soap won’t react with them and the soap's lather improves + shelf life increases.

Citric acid does not lower the pH of soap. Instead it consumes some of the lye and increases the superfat. Add 6 g extra lye for every 10 g of citric acid added to a soap recipe if you want to keep the superfat % at the same level.

How much citric acid should be added to soap?

Usage rate in bar soap is 1-2% of the oil weight.

How to use citric acid

Add citric acid to the distilled water and dissolve completely before adding the lye, or make a separate solution of citric acid and distilled water and add to the oils.

Soap making equipment*

○ Safety glasses - https://amzn.to/3pP99gz
○ Gloves - https://amzn.to/3gjEViA
○ Braun multiquick stick blender (black colored version) - https://amzn.to/35h3GFO
○ Infrared thermometer - https://amzn.to/3fXLx6e
○ Digital scale - https://amzn.to/3zmJSOR
○ High precision scale - https://amzn.to/39YRc8t
○ Spatulas - https://amzn.to/3zo8DdB
○ Funnel pitchers for easy pouring - https://amzn.to/3aYb9h1
○ Silicone molds:
○ Single cavity mold - https://amzn.to/3cAEIW0
○ Silicone loaf mold - https://amzn.to/35gS05S
○ Small wooden soap mold with silicone lining - https://amzn.to/3pVdn6b
○ Cafe de savon wire cutter - https://item.rakuten.co.jp/cafe-de-sa...
○ Guide - https://item.rakuten.co.jp/cafe-de-sa...
○ Swiss star stainless steel vegetable peeler for beveling soaps - https://amzn.to/3ak4VHW
○ Mini mixer - https://amzn.to/35dvECc

Recommended reading:

○ https://amzn.to/3iIllh5

*amazon links are affiliate links. If you purchase a product through a link I have provided I receive a small commission, with no additional cost to you. Thank you for supporting my channel!