Dyeing with Saffron

Heads up that this is a completely non-philosophical post! I've been participating in a group of US-based growers who are trialling saffron as a cash crop. The research group is based at the University of Vermont in Burlington, VT, so I attended their first annual conference last year, planted 500 saffron corms on my own land, and just recently completed a series of dye experiments using different parts of the saffron flower. The stigmas, or female parts of the flower are the expensive spice. Stamens and petals are usually waste materials. I heard that another grower was selling stamens to Buddhist monks for dyeing robes, so I thought I'd experiment with my own crop, augmented by donations of stamens and petals from some other growers on our listserve. (It takes A LOT of stamens to get a usable weight of dyestuff to play with!) 

The following content is the report that I wrote up for the rest of the saffron growing community. I'm putting it here as a view into some of the side activities that go on in my studio and also to illustrate the trial and error involved in figuring out how a dye material works. Hopefully my experiments will prove useful to anyone else wanting to dye with saffron and I welcome comments from anyone who has discovered other methods that work with stamens and petals.

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Dyeing with all Parts of the Saffron Flower
February 2018
Hannah Regier

Using saffron stamens, petals and stigmas obtained from many growers from the saffronnet listserve, I did a series of dye tests on wool/alpaca yarn. Four different mordant treatments were used and several different concentrations of dried flower parts to weight of fiber (WOF) were tried.

Basic Process

1. Combining samples of each flower part and blending together. Some of the stamens and petals appeared to have faded during storage -- I didn’t use the faded samples for these tests.
2. Weighing out amounts for each dye bath. See the chart on the next page for exact proportions of each flower part tested.
3. Bringing the flower parts to a simmer in water and steeping for 1 hour before letting to cool and straining. I used well water with a pH of 6-7 and did not alter the pH on any of the dye tests.
4. Measuring dye liquid into jars and putting 2 gram skeins of yarn with different mordants into each jar. (Standard mordanting process can be found in any natural dye resource.)
5. In a large canning pot, bringing the dye solutions with yarn back up to ~180º and steeping there for an hour, before letting to cool.
6. Rinsing in plain water and washing in mild detergent. Drying.
7. Not finished yet: testing for light fastness by exposing a section of each skein to direct sunlight for several weeks.

Comparing faded and unfaded saffron stamens

Non-faded saffron petals

Weighing stamens for dye

Yarn in dye made from stigmas

​Testing grid
The following grid shows all of the dye tests that I ran with the different parts of the flower, using 4 different mordants. The “% WOF” refers to the weights of plant material I used in proportion to the Weight Of Fiber. All of the tests were done on 2 gram skeins of yarn so 100% WOF would mean I used 2 grams of dyestuff for that test. The codes in each cell are what I wrote on the label of each skein so I could keep track of which dye jar they came from.

Results
Stigmas have by far the strongest dye potential. The dye made from 12% stigmas per WOF was incredibly bright, compared to the darkest shades made from 100% stamens per WOF and 200% petals per WOF.
Despite my research and finding information that refers to saffron as a substantive dye (i.e. not requiring a mordant), dye uptake was consistently better with Alum and Iron as mordants. I am assuming light and wash fastness will also be better on the mordanted samples.

Testing for light fastness by exposing part of each sample skein to direct sunlight for a week or more.

Petal Samples:
The top skein in each section is mordanted but undyed yarn for comparison. Note that the pink color on the rhubarb leaf mordanted yarn comes mostly from the rhubarb leaves themselves, not the saffron.

Stamen Samples:

Stigma samples:
​Note that the 2nd and 3rd samples in each section are from reintroducing new yarn into the used dye baths, called “exhaust dye baths.” The persistent color results, show that the dye is strong enough to be used several times and/or at even lower concentrations.

Conclusions
Given the cost of saffron stigmas, it may be hard to justify using them as a dye material, but I will probably continue to explore it with what I grow myself. The colors obtained from the stamens and petals are nice, but can be achieved with much smaller quantities of other locally found natural dye materials, so using those parts of the saffron flower is probably not worth it, barring any breakthroughs in ways to get darker/brighter tones.
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Many thanks to the growers who sent me their stamens and petals for this experiment:
North American Center for Saffron Research and Development at UVM, Jack Kennedy, Erin Stebbins, Joseph Walls, Sarah Salatino of Full Circle Gardens, Michelle Wells, and Miriam Haas.