A Chemistry Lesson

It’s one thing to see a surprising dye color emerge straight from its plant/fungal source such as the pink hiding inside avocados, but it’s another entirely to observe a pale, barely-there color turn vivid with the addition of another solute. A little bit of chemistry and patience can take a small dye palette and expand it across a whole spectrum of colors.

Grey and copper in the same skein from iron and ammonia post-processing of a mystery coral mushroom

From Suspicion to Wonder

On a trip to Mendocino, we managed to pick up a delightful large hunk of coral mushroom in addition to the usual chanterelles and hedgehogs. Being the less easily identifiable specimen with questionable edibility, the coral (likely a Ramaria sp.) wound up forgotten in the fridge. I was curious about its dye properties because the mushroom oxidized wine-colored where it was cut, and some species of Ramaria will render pinky-purples. Into the dye pot it went with 50g of wool and a shrug. It simmered for an hour and sat out overnight.

Undyed on the left, mystery white coral mushroom on the right

The bath itself had a yellow tinge, and in the poor lighting of winter evenings, I couldn’t tell if the yarn had done much. More shrugging ensued. Once the yarn dried to reveal a pale sickly-yellow, I considered “redyeing” the yarn with a different plant, but decided to get scientific instead. What if a more vibrant color lay just beneath the chemical surface?

Alissa Allen of Mycopigments fame has a testing strategy for teasing out the most fruitful dye results from a substance. It allows nine simultaneous chemical experiments to be run with a small amount of dyebath, which makes it a quick matter to make informed choices about how you might want to use the dyestuff in the future. I cut a few snippets of the coral-dyed yarn and ran a makeshift mordant and pH test, as outlined below:

Quick-Test for Mordants and pH


  • Unmordanted wool
  • Wool pre-mordanted in alum
  • Wool pre-mordanted in iron
  • 3 mason jars
  • Cooking pot large enough to hold all 3 mason jars
  • pH paper
  • Dyestuff to test
  • Household vinegar
  • Household ammonia
Nine experiments run in a short time makes it easy to decide how to treat the dyestuff in the future


  1. Grabbing a 2-foot strand from each hank of wool, tie different numbered knots in each strand to help keep track of which is what. (One for unprocessed, two for alum, none for iron, for example).
  2. Tie the three strands together in a “tester bundle”.
  3. Make three tester bundles. It may be helpful to tie additional knots in the tester bundles to discriminate them later.
  4. Make a dyebath as usual from the dyestuff (simmer for an hour) and split into three parts. A double boiler method with mason jars in your dye pot works great for this. Label the jars Neutral, Acid, and Base.
  5. In the Acid jar, pour in enough vinegar to lower the pH to 4.
  6. In the Base jar, pour in enough ammonia to raise the pH to 9.
  7. Place a test bundle in each jar, and simmer for 30 min to an hour. (You can often get away with less time, since the dye-to-fiber ratio is higher than usual.)
  8. Remove the bundles (take note of which bundle comes from which jar) and wash/rinse. Let dry.
  9. Observe your results!


Dipping only part of the iron-yarn into ammonia creates a variegated skein, much like synthetic hand-dyes.

Since I had already dyed a hank with the coral mushroom, I added all these modifications to the yarn sans dye bath, but the results are evident. In this case, iron-treated yarn took a sickly yellow to a lovely grey that gleams like silver in the sun. Ammonia-processing the iron yarn then turns that silver to copper.

This made an easy decision of what to do with the whole hank, which I would have disappointedly tried to dye with onion skins otherwise. Thanks to science, I have a variegated silver/copper hank to add to my collection.


The final product!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s