japanese indigo leaves

How to extract indigo out of dried leaves

This is a blog post on ‘how to extract indigo out of dried leaves’. The dried leaves that I am using are Japanese indigo (Persicaria tinctoria) leaves as they grow well in the UK weather. Here is an old blog post on how to grow them. To encourage more plant growth one needs to harvest the leaves regularly but sometimes with other activities happening it is hard to keep up with extracting indigo from these freshly harvested leaves. Last year I dried some of these leaves as a result. They dry and keep well. Back in August during the harvesting season life is so busy that one has no time to make use of fresh leaves therefore I dry them up to save use in the winter. Note the levels of indigo in the leaves do drop once dried something to be aware of.

This method has been described by John Marshall, the living indigo legend, in his book ‘Singing the Blues,’ so it is nothing new. Here is where to purchase his book. However, I would like to describe how I extract indigo out of dried leaves. It’s a simple technique, but there are various ways as well.

japanese indigo leaves

How to extract indigo out of dried leaves

To extract the leaves one just needs to soak the leaves in lukewarm tap water. Soak till the water becomes green brown murky color. Separate the solution with the leaves by draining them in a separate container. Add more fresh water so as as to extract more indigo out of the dried leaves.

Then extract it using hydrated lime/ calyx (Calcium Hydroxide). The calyx helps to settle/ separate the indigo from the green-brown solution. Just use the minimum of calyx required. Using a coffee filter put this sediment to further filter out the water to store in powder form. Like how does one extract indigo out of fresh leaves.

Use it for organic indigo vats as these type of vat requires pure natural indigo. It is possible to use thiox vat but I don’t use it much nowadays due to safety reasons. It is quite easy to extract but time-consuming. This is a great wintertime activity when fresh indigo is not available and when the homemade indigo powder is on the low level.

Thank you for reading and dropping by.

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