A Holiday Feast of Colorants

The following is a post by Cindy Connelly Ryan, Preservation Science Specialist, Preservation Research and Testing Division (PRTD). Cindy does conservation science research and analysis of collection items using a variety of analytical techniques from x-rays to light beams and is an expert in the re-creation of obsolete historic artists’ materials.

“It smells like curry in here. Are you guys cooking lunch in the chemistry lab?” asked my puzzled colleague.  If the Library Safety Office is reading this, I hasten to assure you that we were not! I was making some colorant samples for our collection of reference materials. But two of the plants I was simmering that morning to extract their colorants were indeed the spices saffron and turmeric. Today’s post explores a little known link between fall’s glowing colors and its festive foods: traditional dyer’s materials that are also edible. Although most of the colorants found in the Library’s collections are not edible, and some are even poisonous, a surprising number may be in your kitchen! Join me for a feast of foods and colors.

We’ll begin with a few appetizers. First up, a lemony sumac soup (The new food of life: a book of ancient Persian and modern Iranian cooking and ceremonies, page 74) with onion and chopped herbs. Sumac varieties grow worldwide, and the crushed seeds are an especially popular seasoning in Middle Eastern cooking, the star of Fattoush salad (Artichoke to za’atar: modern Middle Eastern food, page 289), flatbreads with za’atar, and as a garnish for kebabs and dips.

Less well known today are sumac’s craft and artistic uses. The barks and leaves yield tannins used for textile dyeing and leather tanning, and Swedish naturalist Pehr Kalm noted the use of sumac for dyeing wool orange by North American settlers in the early 1740s. Sumac’s use by Native Americans is centuries older, based on archaeobotanical seed records and travelers’ observations from the 1580s. And sumac berries and bark have been used as trade goods since at least the 11^th century, as we know from the excavation of a wrecked ship off the coast of Türkiye.

Another yellow colorant traded from the early Americas to Europe is annatto, or achiote, long used as a textile dye in Peru and traded as far as Europe by the 16^th century, where it was used to dye silks and make watercolors, as this 1764 treatise instructs. Annatto is still used to deepen the orange hue of foods, including cheddar cheese (go check your fridge!), and is especially common in recipes from the Yucatan region of Mexico. For our second appetizer, let’s fire up the grill and enjoy achiote paste with a bit of salt and lime juice rubbed onto skewers of potatoes, peppers, shrimp, or fish.

Perhaps the most prized of the delicious yellow dyes is saffron, long used for manuscript illuminations in India, the Middle East, North Africa and Europe, as we know from artists’ manuals including those of Ibn Badis, Cennini, and others. Kalm noted its wide cultivation by southern New Jersey settlers in the 1740s, likely for both culinary and color use. As a spice, saffron is essential in rice-based dishes such as paella, plov, and biryani, and has been used since the Roman era in seafood dishes and soups. To honor that lineage, today’s menu includes a traditional southern Italian pasta dish with a saffron cream sauce (The Authentic Pasta Book, page 239).

We shall gloss over the roasting of large birds, except to collect some feathers to make writing instruments. But let us not overlook the stuffing!  Now, I have no intention of starting a comments section war, as I am certain that your family’s cherished stuffing recipe is far superior to any I might dare suggest. I will just note that nearly every good stuffing contains onion, and quite a large number use walnuts. The skin and rind of these two ingredients are splendid sources of colorants.

The earliest notes I know of about making walnut hull ink appear in the 1701 edition of William Salmon’s Polygraphice, the widely reprinted and even more widely copied from ‘wiki-how’ of its era for artisans, covering topics from drawing and engraving to varnishing, gilding, cosmetics, and perfumes. Walnut hulls’ used as a textile dye can be dated back further into the late Middle Ages. Onion skins have left a thinner historic record, but
are widely popular in how-to videos and blogs as a beginners’ or school dyeing project, as they are easy to find, easy to use, and non-toxic. Onion skin colors can be used to make a yellow watercolor, and there is abundant documentation of their use to color all manner of other things, from textiles to Easter eggs.

For our next dish, a salad: tomatoes with turmeric yoghurt, from this book but perhaps it is easier to find here. The humble turmeric root does triple duty as a spice, as an anti-inflammatory medicinal in the Ayurvedic tradition, and as a colorant. This mid-18thC Tibetan thankgka gifted to the Library in 2010, recently visited the PRTD lab for light sensitivity testing before an upcoming exhibition. Its patterned silk cover is likely dyed with turmeric, and it proved to be pretty light sensitive (you can read more about that project in this blog post).

Our feast would not be complete without cranberry sauce, either this classic version (Veganomicon, p. 213) or NPR’s infamous cranberry horseradish sauce, which every year I swear I’m going to try.

We know from technical studies of surviving artifacts that eastern woodlands Native Americans used various berry juices to dye quills as used in the decorative elements on these flutes in the Library’s Dayton C. Miller collection. Possible dye materials included cranberries – or blueberries, elderberries, blackberries, or grapes, any of which we can use to make a pie!  Although these anthocyanin colorants are not wash-fast on textile fibers, manuscript illuminators’ recipes for elderberry, mulberry, and blueberry-derived colorants are known from the Renaissance and Middle Ages.

Perhaps a guest will bring a second pie?  Pre-made fillings may likely contain Natural Red #4, the insect-derived colorant cochineal. Though cochineal is not an ingredient home cooks typically use, it is common in commercially prepared drinks, jellies, candies, and more. Prized for its brilliant scarlet hue and relative light stability as a textile dye, this colorant also has a long history of use in cosmetics and as an artists’ material. This LC magazine article and the image below contain images of making cochineal inks following notes in an unpublished Revolutionary War era dyer’s notebook from LC’s manuscript division, and my colleague Mary Elizabeth Haude explores cochineal’s Mesoamerican usage in this excellent Story Map.

Time for coffee or tea! These drinks form brown stains, the bane of dentists everywhere. Although not traditionally used colorants, coffee and tea are being explored by a number of contemporary artists as an artistic medium both serious and whimsical.

Thank you for joining me for this feast of colors. If you have over-indulged, perhaps an antacid?  Some over the counter indigestion medications contain calcium carbonate, which we cultural heritage scientists frequently encounter as the common white pigment chalk.

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