Red cabbage color test

[Obsidian]

After reading this post http://www.soapmakingforum.com/showthread.php?t=52049 I decided to try using red cabbage juice to color soap blue and see if it really does make smelly soap.

Juice, was quite strong smelling

Juice with lye. It turned dark green at first then went bright orange. Didn't notice a increase in smell

In the mold. I scented on bar just to see if the juice affected FO at all.

When mixing the lye into the oils, it smelled strongly of ammonia but it seems to be fading already. I had enough batter to pour a small bar that I will be CPOP to see how that affects the color change.

 

[lpstephy85]

Darn lye monster and its changing color powers!! I would love to have a natural purple that looks like that!

 

[Obsidian]

You and everyone else, its such a pretty purple. So far this seems to be a fail. The soap is staying a light creamy color, even the bar that was fully gelled. There is no hint of green or blue developing.
The unscented bar smells faintly of cabbage but I suspect it will fade with time, no smell is detectable in the scented bars.

 

[MorpheusPA]

You and everyone else, its such a pretty purple. So far this seems to be a fail. The soap is staying a light creamy color, even the bar that was fully gelled. There is no hint of green or blue developing.
The unscented bar smells faintly of cabbage but I suspect it will fade with time, no smell is detectable in the scented bars.

Is it a reversible chemical change, or does the lye permanently alter the color?

If permanent, adding the cabbage to the oils or at emulsion/trace might keep it green or blue. Adding it to the lye just kicked it all the way up to orange.

If reversible, it might also require that the free lye go away, which may not happen for some time yet.

 

[Obsidian]

I had assumed it was reversible but it doesn't appear to be since its still colorless. I'll have to juice the rest of my cabbage and play around with it, see if I can get it to reverse.

 

[CaraBou]

I love your insatiable appetite to try anything in soap. I never know what will come next! Except this time -- more cabbage!!

 

[Obsidian]

Some body has to try it, you never know when the next amazing additive will be found lol. Soap is staying pale yellow, you can hardly tell there is any color in it at all. I can't see anyway to keep the blue coloring except maybe by adding it to white rebatch.

 

[kchaystack]

The color change is due to the pH of the solution that it is in because red cabbage contains anthocyanin. So the only way to keep the red purple color is to keep the pH slightly acidic ( around 6).

Since soap has a pH usually around 9 or 10, and you can not adjust its pH down w/o breaking the soap, I do not think you will be able to get that color back.