<p>Try mixing the unfermented indigo powder with water in a bowl, and '<em>beating</em>' it, using a smaller bowl to scoop it up and pouring it back until the mix turns blue.</p>

<p>Consider adding <a href="https://www.coyuchi.com/the-naturalista/indigo_dyeing/" rel="nofollow noreferrer">lye</a> [NaOH] or <a href="https://thekindcraft.com/the-process-indigo-from-plant-to-paste/" rel="nofollow noreferrer">slaked lime</a> [Ca(OH)2] to help the fermentation process. The effectiveness might depend on how the unfermented powder was produced, though.</p>

CC BY-SA 4.0
2020-02-05T14:57:44.730Z
2020-02-05T14:57:44.730Z
Joachim
<p>I have bought indigo powder to color my soaps blue (cold/hot process saponification). Unfortunately I received something which color is closer to match than blue jeans...<br>
After some internet research I found that what I have is unfermented indigo powder, while the blue colorant is made with fermented indigo; very detailed information <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2018.02196/full" rel="nofollow noreferrer">here</a>.</p>

<p>My question: does someone have a recipe to ferment my green powder to get something blue I can use in my soaps? I found a lot of vat recipes, but that's to dye fabric and I don't think it will work in soaps.</p>

CC BY-SA 4.0
2019-11-14T11:22:53.857Z
It seems the green indigo needs to oxidize. Have you tried mixing it with water and dying cloth with this mixture, to see if it oxidizes while drying?
Joachim
CC BY-SA 4.0
2019-11-14T22:47:01.180Z
That article says that blue indigo is made by *oxidation*, while fermentation does the reverse, *reduction*.
Buzz
CC BY-SA 4.0
2019-12-24T09:27:01.877Z
I did not try to dye cloth with it, but it is exposed to air when the soap dry. However the color did not change.
Oneira
<pigments><soap-making>
How to ferment green indigo powder to make it blue
Oneira
# How to ferment green indigo powder to make it blue

(Asked by: username_0 on 2019-10-29)

I have bought indigo powder to color my soaps blue (cold/hot process saponification). Unfortunately I received something which color is closer to match than blue jeans...  
After some internet research I found that what I have is unfermented indigo powder, while the blue colorant is made with fermented indigo; very detailed information [here](https://www.frontiersin.org/articles/10.3389/fmicb.2018.02196/full).

My question: does someone have a recipe to ferment my green powder to get something blue I can use in my soaps? I found a lot of vat recipes, but that's to dye fabric and I don't think it will work in soaps.

**Tags:** pigments, soap-making

> **Comments:**
> **username_1**: It seems the green indigo needs to oxidize. Have you tried mixing it with water and dying cloth with this mixture, to see if it oxidizes while drying?  
> **username_2**: That article says that blue indigo is made by *oxidation*, while fermentation does the reverse, *reduction*.  
> **username_0**: I did not try to dye cloth with it, but it is exposed to air when the soap dry. However the color did not change.  

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## 1 answers

### Answer by username_1 on 2020-02-05. Score: 1

Try mixing the unfermented indigo powder with water in a bowl, and '*beating*' it, using a smaller bowl to scoop it up and pouring it back until the mix turns blue.

Consider adding [lye](https://www.coyuchi.com/the-naturalista/indigo_dyeing/) [NaOH] or [slaked lime](https://thekindcraft.com/the-process-indigo-from-plant-to-paste/) [Ca(OH)2] to help the fermentation process. The effectiveness might depend on how the unfermented powder was produced, though.


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