According to a 2002 Phytotherapy Research journal, this aromatic spice wins the most significant contributor of antioxidant to human diet. It’s mouth-watering and tear-inducing scent has wafted from the tables of various cultures: from the nearly 4,000 year-old Mesopotamian cuisine (3 stone cooking tablets actually document this!), France’s delectable Onion Soup, a Senegalese dish called Yassa, fastfood joint’s infamous Onion Rings, to the Filipino pan-fried then simmered Bistek.
Touted with anticancer, antimicrobial, anti-inflammatory and antioxidant properties, this humble vegetable comes in three colors (white, yellow, red) and is worshipped in Egyptian history; it’s concentric circular structure symbolized eternity and thus granted the humble onion burial with the Pharaoh in his journey to the next life.
Gastronomic and curative powers aside, the onion is also a known ingredient for dyes—specifically, the onion skin. It contains a plant pigment known as pelargonidin, also naturally occurring in blueberries, plums and kidney beans. The resulting color is in the range of burnt red to rust orange, golden yellow, and rosy to earthy brown, depending upon the color of the onion.
So don’t throw away your onion skins yet! Load them up in a pot, preferably aluminum, which will have the same effect as an alum mordant.
Mordant (n.) – a chemical that fixes a dye in or on a substance by combining with the dye to form an insoluble compound. (Merriam – Webster)
Or in other words, it makes the color stick!
The onion skins are simmered for 30 minutes to an hour to extract the color. The skins can also be soaked for a few days before straining it out and putting the warm, pre-soaked fabric in. Put the heat on for an hour.
The longer the fabric is soaked in the dye bath the more saturated the color will turn out.
Restaurant proprietors and green grocers can potentially tap into the natural dye economy. For as long as there are onion lovers, there will be a sustainable supply of Onion’s golden tears.