Woad indigo is my favorite natural dye. It is versatile, can be used on nearly any type of natural fiber without pre-mordanting, can over dye anything no matter how many natural dyes were used on it before, and all it’s shades are beautiful.
Whether you do woad harvesting in the spring, the summer, or the fall, preserving your indigo harvest is important. If you live in an area with plenty of wild woad, where woad is classified as a noxious weed to be eradicated. Then a spring harvest and extraction party may be just the thing, and that may spill into summer and fall parties as you try and actually get rid of it… It’s a very determined plant (and the worms love how it’s roots break up hard soils).
In fall, there is a haste to harvest and process woad before the frost finishes it’s ravages. Often the fall harvest, either second or third, can be nearly as heavy as the first late spring or early summer harvest. However, fall is often a busier time of year, with back to school and the late season preservation and winter food preparation.
At any time of year, can you preserve woad for later use? Short answer, yes and no. While there is no way to preserve the full potential of woad in the leaf, there is the ability to preserve the extracted indigo.
How to Preserve Woad Indigo:
From the time you pick your woad leaves, until the extraction vat is fully processed, you may be losing indigo potential. The faster you are from picking to extraction, the more indigo you will get from those leaves. That is how woad indigo works.
To preserve indigo, you must complete the full extraction, from cooking, pH changes, and oxidization. The indigo molecules are not stable until they are fully oxidized in the extraction. After you have extracted the indigo, this extract can be preserved.
The first step after extraction is getting the indigo to precipitate in the bottom of your woad extraction vat. Draining off the top liquid, dividing into jars, and adding water and letting it precipitate again is the method I use to be able to see my indigo dye.
After the indigo is precipitated, you can do one of two things. Either dry it, in a shallow dish until you can flake off the indigo and bag it for later grinding and dying. Or, you can freeze the precipitate and just thaw it when you want to dye with the indigo.
Either drying or freezing will preserve the indigo precipitate and enable you to enjoy woad indigo and woad blues whenever you want.
Back To You:
I prefer drying and grinding the indigo precipitate, since it is not impacted by lack of power and doesn’t take up valuable freezer space. It is, however, a more labor intensive method of preservation and if you will be using the indigo up within 3-6 months I would advocate freezing over drying.
What about you, how do you preserve your natural dye harvest? What techniques have you used to give you winter natural dye options? Leave a comment.