Indigo First Harvest 2020: Step 2

Indigo First Harvest 2020: Step 2

If you're just joining in, make sure to start with the Step 1 post to get the outline of the process I'm using.

I haven't warned you yet. The next step is fermentation, and it will likely come with...some smells. If you're only doing small containers it won't be such a big deal, but with my large 50-gal barrels...let's just say I wear old clothes and shoes, and my family is happy that I don't do this too close to the house!
Step 2: Fermenting
This step is primarily about timing. If the weather is hot and sunny, the process will go a lot faster than if it is cool and cloudy. It also depends on the size of your container. I check on the progress several times a day. Make sure the leaves are completely submerged in water, or they will dry out on the surface and won't ferment.
The weather does need to be warm enough to make the process work, at or above 70 ºF during the day. Read Ecotone Thread's blog for ideas about what to do in cooler weather.
When the leaves are no longer fresh green, and the water is the color of blue-green antifreeze, you are ready for the next step!
  • The fermenting process breaks down the leaves to release indigo (indoxyl) and enzymes. The indigo at this stage is less stable, and if the leaves ferment too long (more than 3-5 days) the indigo will start to break down. 
  • If after 3-5 days your water is the color of antifreeze, but you still have a lot of fresh green leaves, move them to a new fermentation container and let them ferment longer. That way you don't risk losing the indigo you have extracted, and maximize how much indigo pigment you harvest.
  • My 50-gal barrels have the advantage of making it easy to keep a lot of plants completely submerged, but the disadvantage of warming up unevenly. The top always gets warm much quicker than the bottom, so the plants on top will ferment much more quickly. I try to stir the plants a couple times a day to stir the warm water on top into the cooler water below.


Fermenting indigo Starting to turn antifreeze green, but not done yet...
Fermenting indigo Not yet...
Fermenting indigo

Ding ding ding!

We have extracted indigo!

Fermenting indigo Even a nice iridescent blue sheen on top.

Before the next step, we are now done with the plant material and need to remove it as best we can. It's a great addition to your compost. I just put mine right back in the indigo garden.

 Removing fermented indigo Scooping it out with a rake...

Indigo compost

...and putting it around my cut plants in the garden as mulch.

Now that we have some unstable indoxyl in water, we need to stabilize it and alkalyze it.

Onwards to Step 3!

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