Get an (Ompha)lotus that purple!

An abundant mushroom, the Western Jack O’Lantern (Omphalotus olivascens) and its cousins are often mistaken by amateur mycologists for the much more edible and desirable chanterelle. In addition to delivering a nasty stomach ache to the unwary, some report that Omphalotus harbors a delightful surprise ability to glow in the dark. Much like the trickster symbol of Halloween for which it is named, this mushroom is known to tease dyers and be a little stubborn with its most luscious of colors. It will impart any one of a range of greens to browns to greys, but with a little gentle coaxing, we can get a purple.

Purples and olivey browns achieved from a generous bunch of Omphalotus olivascens.

Conveniently, Omphalotus tends to grow in clusters, and its specimens are large. If you happen upon some, it is very likely you have enough to dye with. The mushroom tends to grow around hardwood stumps and roots, and appears from fall to mid-winter. Importantly, only the Western Jack O’Lantern (Omphalotus olivascens) is a dyer—its eastern cousins won’t do much more than stain your hands orange. Also important, mushroom dyes like this one don’t play as easily with plant fibers, so it’s best to stick to animal fibers (wool, silk) or nylon.

Omphalotus olivascens grows in clusters at the base of hardwood stumps.

Unlike a standard dye mushroom recipe where you might simmer the mushrooms for an hour, then simmer the yarn in the mushroom bath for another hour, the purple from Omphalotus requires more active attention. Alissa Allen of Mycopigments describes a recipe like so:

Using fresh, dried or frozen mushrooms at one part dried fungus to one part fiber by weight, or two parts fresh or frozen fungus to one part fiber by volume, simmer unmordanted, washed wool at 170°F until ideal purple is achieved (a tiny splash of vinegar may help). Pull fiber and cool before rinsing in cool water. Line dry in a shady place, out of direct sunlight.

Important to note: “ideal purple” is a fine line of 5-15 minutes—get greedy with it and keep the yarn in the bath too long, and your purple may get washed out and turn grey or taupe. Additionally, since the yarn is only held in the bath for 15 minutes instead of an hour or more, it is likely the exhaust bath will contain a great deal of dye. To fully exhaust the bath, you may need 5x-6x or more fiber by weight.

Expectations

Not much is written about dye processes with Omphalotus, even though its pigment properties are mentioned in the likes of mycologist celebrity David Arora’s pocket field guide. I did have the chance to work with this dyer at a Mycopigments workshop, and the fleeting chance for purple excited me a great deal!

Omphalotus olivascens a bit past its prime: sharp, deep gills, cap turning up at the edges at maturity, orangey brown with a deeper olive hiding just below the surface. It looks like a dark pigment is just waiting to emerge!

I kept iron sulfate close at hand in the event that purple remained elusive. While muted periwinkle grey is a lovely color, I wanted the option of converting it to green with an iron dip.

Materials

Dried Omphalotus olivascens and bare yarn
  • five 50g hanks of superwash sock yarn
  • 50g of dried Omphalotus olivascens, collected just 1 week prior
  • 4 quart soup pot (just like in chemistry class, your dye utensils should not double as food utensils)
  • chopstick or tongs (not used for food)
  • enough water to cover the dried mushrooms and yarn (to control for variables, it’s advised to use distilled and/or filtered water. I used tap.)
  • a few drops of dish soap
  • a splash of vinegar
  • pH strips
  • thermometer (not used for food)

Procedure

Yarn looks like noodles when submerged in a dye bath
  1. Soak the yarn in tepid water with a few drops of dish soap for 30 minutes.
  2. Fill the pot with water and add the dried mushrooms. Heat on the stove until the bath is around 170°F. (I used hot tap water (120°F) to start, then plopped the mushrooms in at 130°F.)
  3. Rinse and squeeze all the soapy water from the yarn. Do not wring, as this will stretch the yarn fibers.
  4. Submerge one 50g hank of yarn in the dye bath. Since my mushrooms hadn’t had a lot of time to sit, I left the pieces in the bath. I also enjoy the slightly mottled look that occurs when some yarn touches the dye specimens.
  5. Check the yarn every couple of minutes. A splash of vinegar after the first 5 minutes to get the pH down to 5 or 6 may help that purple come out if things are looking a little dull. Remove once it has achieved a desired color (for me, this was around 10 minutes).
  6. Allow the yarn to cool, then squeeze out remaining water. Again, do not wring, as this will stretch the fibers. You can rinse the yarn in cool water, or hang to dry without rinsing. I opted not to rinse.
  7. Run steps 4-6 with additional hanks of yarn to exhaust the bath.
  8. Optionally, add a couple of grams of iron sulfate, or use iron mordanted yarn, to the dye bath and watch the bath darken to olive or brown. This will tend to pull more pigment into the yarn and leave less in the exhaust bath.
  9. Hang to dry out of direct sunlight.

Results

Five rounds of dyeing with 50g hanks each, with only 50g of Omphalotus olivascens

I completed five successive dye rounds with this collection of Omphalotus. In Round 1, I was a bit “greedy”, and while I removed the yarn around 10 minutes in, as it was cooling, I thought I may as well try for a deeper, darker purple, so I resubmerged the yarn for another 5 minutes. This resulted in some greys and browns coming through.

Round 2 was treated similarly, and it has those greys still coming through. For Round 3, I pulled the yarn at 10 minutes and resisted temptation, and received a lovely true lavender as a result.

For Round 4, I put a teaspoon of iron sulfate in the dye bath, anticipating the dye to go toward green/olive as I’ve read. To my surprise, “green” meant a brown with olive undertones, just lovely. The yarn took up a lot of pigment still, so I opted for a Round 5 to really maximize the gift of the mushroom.

Once I put the 5th hank in, it was readily apparent the bath didn’t have much left to give. I left it to sit for a half hour or so, then turned the heat off and let it sit until it was cool enough to handle with bare hands. A delightful pale olive emerged, with small flecks of a brownish red from where the yarn touched the mushroom bits. I did wonder if there was yet still more to the dye bath, but I was nearly out of yarn at this point, and I had so much beauty before me already, that I stopped there.

Conclusion

What a treat this mushroom was—truly a gift that kept on giving! It provides a very active dye experience compared to other mushrooms and lichen where patience is a better friend. Omphalotus demands attention, but rewards the dyer with such a spectrum of possibility.

Chemistry at Play

pH

A slightly lowered pH absolutely turned my dyebath from a multicolored brown/grey into a purple. The yarn tended to come out of the bath with a tint of red, but as it dried it went more blue/purple/grey.

Time

This dye experiment emphasized the inherent complexity and beauty of natural dyes. It’s as if there is more than one pigment molecule at work, or the pigment molecules are more complex, such that the final colors respond so differently to varied light sources, and subtle shifts in hue emerge with varied lengths of time in the bath and in subsequent rounds of exhausting the bath.

Catherine Ellis thoroughly demonstrates the role time-in-bath plays in eucalyptus dye. Yellow hues emerge first, then are overtaken by the brown of tannins if the fiber is left in longer. In a different way, Omphalotus purples emerge earlier but are overtaken by greys, but it’s not the cook time of the mushroom in the dyebath that seems to affect this. I was under the impression the purples would “cook out” if the bath were left at heat too long, but it really seems to be the time of the interaction with the yarn that plays the biggest role. This can be observed in the Round 2 and 3 samples, where purple is still very present, though the bath had been running at around 50 minutes total at that point.

Mordants

Omphalotus is responsible for the purple (upper right) and greens (bottom)

Iron is usually said to turn an Omphalotus bath green, rather than the olive-toned brown I observed. I suspect I didn’t get greens because the greens may be an early-stage pigment that had been depleted or overtaken, much akin to the eucalyptus examples by Catherine Ellis. It’s hard to say, though—it’s possible I used too much or too little iron, though my result really just seems like the green is missing.

Iron certainly did accelerate the uptake of dye in a later exhaust bath, and this may be a technique I use with other dyestuffs. Pastel gradients are beautiful, but using iron on a later exhaust may help an iron-mordanted color from becoming too dark, but still have adequate saturation.

Ratio of Dyestuff to Fiber

It seems tempting and entirely possible to use less than the 1:1 recommendation of mushroom to fiber. The Round 3 sample still holds so much purple color, and sopping up the dye with the addition of iron reveals that Round 4 still had quite a bit going for it, too. But much like making tea, using more dyestuff for less time is what gives the intensity of the purple. Reducing the amount of mushroom likely results in pastel purples if the same time is kept, or intense taupey greys if more time is used.

Exhaust Baths

Lastly, this dye experiment piques my interest in exploring exhaust baths. Different color tones do emerge at different times, and some are more readily taken up in the earlier exhaust baths than in later ones. The purples that emerged in Round 1 and 2 definitely have more red tones than in Round 3, and they had the red tones even before I got “greedy” and resubmerged the yarn for the extra five minutes. As mentioned above, I also suspect that iron-greens are an early stage pigment, rather than a later stage as I attempted.

Resources

Fresh Omphalotus olivascens is known to glow in the dark!

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