How to Make Red Cabbage pH Indicator to Test pH of Shampoo

how to make red cabbage pH indicator to test pH of shampoo juicygreenmom

With all the buzz about shampoo needing to be the right pH for your hair (there’s a lot of talk about how the traditional no-poo baking soda method is too alkaline for hair), I was itching to test out my current DIY shampoo recipe with some litmus paper. I asked on my local swap page if anyone could provide some, and a teacher on the page told me that you could actually use red cabbage as a pH indicator. Mind. Blown. I got a few strips of litmus paper as well, so I decided to geek out with a science experiment to test pH of shampoo with both methods!

It was surprisingly easy to make the red cabbage pH indicator – all I did was chop the cabbage, pour boiling filtered water over it and let it sit for about 10 minutes. I strained the water and voila! My very own pH indicator! I compared the colour of the red cabbage liquid to my Litmus Paper to really test it out.

chopped red cabbage
red cabbage liquid after soaking in boiling water for 10 minutes

Red Cabbage pH indicator colours

ColorRedPurpleVioletBlueBlue-GreenGreenish Yellow

pH of filtered water with litmus paper: 6. Red cabbage indicator looked like a deep shade of purple to me (violet?).


pH of Green Beaver liquid castile soap with litmus paper: 7. Red cabbage indicator was a more blue purple like indigo.

Shampoo Recipe (that converted me to DIY hair care)

pH of my DIY shampoo with litmus paper: 7. Red cabbage indicator was pretty much the same – a deep blue purple like indigo.

I’ve heard that castile soap is alkaline, so I was surprised when I found that the brand I was using had a neutral pH of 7. Perhaps it’s just slightly alkaline, but not enough to make it to a pH of 8? Regardless, the sad news is that my beloved DIY shampoo recipe is not optimally pH-balanced for haircare (supposedly hair has a pH between 4.5-5.5).

I also tested the pH of aloe vera juice, because I’ve heard it used in other DIY shampoo recipes.


pH of aloe vera juice with litmus paper: 4. Red cabbage indicator was a mauvy-reddish-purple shade.

So perhaps I will experiment with aloe vera juice as another possible ingredient in a DIY shampoo… Hmm! The nice thing is now I know what mauvy/purple shade pH 4 is, so I feel comfortable testing future products with the red cabbage pH indicator method. Stay tuned for more DIY hair care adventures!

Do you know the pH of your shampoo?

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