Natural indigo is the newest old choice for sustainably dyeing jeans.
Did you know that dyeing clothing blue goes back more than 5,000 years, when our ancestors in India, East Asia, and Egypt used the blue dye from the Indigofera Tinctoria plant to dye their clothes? There is even evidence that weavers in ancient Egypt inserted blue stripes in the borders of plain linen mummy cloths.
The Indigofera tinctoria is a tropical plant belonging to the pea family. It was cultivated, became a staple agricultural crop, and was used to dye clothing to get a dark blue colour. Extracting the dye from the plant is a long process whereby the leaves are fermented, and the extracted liquid is allowed to oxidize. A blue sediment will then form at the bottom of the vat. Once formed, the sediment is collected, dried into cakes, and can be sold for dyeing purposes.
Indigo was often referred to as Blue Gold because it was an ideal trading commodity, high value, compact and long-lasting. Unfortunately, due to the laborious process of extracting the blue dye, natural indigo production could no longer meet the demands of the clothing industry in the 19th century.
Synthetic indigo became an alternative, and it is still being used today. A variety of synthetic chemical processes have been used to produce indigo, all of which involve combining a series of chemical reactants under controlled conditions. Fashion companies like the use of synthetic indigo because they can produce the same colour, blue, every time. Compared to natural indigo for sustainably dyeing jeans, whose colour will vary depending on where the indigo was grown and the weather at the time.
One of the risks of synthetic indigo is the amount of chemicals used in its makeup, which creates pollution. The denim industry uses more than 45,000 tons of synthetic indigo a year, along with over 84,000 tons of sodium hydrosulfite as a reducing agent and 53,000 tons of lye. In many factories around the world, runoff from synthetic indigo goes into the rivers, turning them blue and contaminating them. Many fish die as a result, and the health of the workers and residents is often negatively affected.
The use of natural indigo is far better for sustainably dyeing jeans because after the pigment has been extracted, the plant residue can be composted and used as a fertilizer. Moreover, because it consists of no chemicals, the water can be reused to irrigate crops. Natural indigo can also be traced from the country of origin to even the farm on which it was grown. These factors are becoming more important in the environmental movement.
Levis Strauss & Co. is one of the pioneers of the jean movement and is known for its iconic jeans. The company is also leading in using natural dyes and sustainably dyeing jeans for many of its denim lines. The indigo used is sourced locally by Stony Creek Colors. This US-based company grows plant-based dyes on former tobacco farms in the South, providing income to farmers shifting their operations to different crops like indigo. Levis’ Fall/Winter 2022 line WellThread increased the use of the natural indigo dye in sustainably dyeing jeans and many of its other items. Stony Creek Colors has also partnered with other jean brands like Wrangler, Lucky Brand and Patagonia to provide them with natural indigo dyes for sustainably dyeing jeans.
The blue colour of jeans is so iconic and is likely to be a trend for decades to come. The hope is that more companies will avoid using synthetic dyes in their jeans and support local farmers who are growing natural indigo dyes for sustainably dyeing jeans. If we can make this switch happen, it will be better for our health and the environment.