Sustainability in Denim

Even the average jeans customer knows already that denim belongs to the bad guys concerning sustainable issues. Our industry consumes lots of water, uses hazardous chemicals and with all the super stretch denims we contribute to the microplastic pollution.

But the awareness is raising, new possibilities were developed over the past years and there are many ecological materials and treatments available already today.

In this series, we take a look on the impact of denim and jeans, but we put the focus on the progress of sustainable alternatives.

The time where sustainable decisions came with limited possibilities in design and outcome is a thing of the past!

No.3: Waterless indigo dyeing, how we can reduce water use

In the last episode, we talked about recycled cotton fibres and about creating new denim fabrics with a portion of used jeans to minimize the impact. In case you missed this article, read it here. Today we will dive literally into the water, or let’s say into water use and how we can decrease it. Water is a precious and endangered resource, and more and more natural bodies of water get contaminated.

In the supply chain of a jean are three main impacts parts of high water use and possible pollution:

The first one is the cultivation of cotton; the thirst for this crop depends a lot on the area and the weather, although the average water use of cotton is quite high. Plentiful applied pesticides and fertilizers reach the waterways and threaten the rivers close by.

The second part is dyeing. The conventional technique uses lots of water and results in plenty of polluted wastewater. The denim industry is aware of that problem and has a solution ready. More on this topic later.

The third point of water impact would be industrial washing, we will take a closer look within a future episode of that series.

Before talking about dyeing in detail, we need to talk about the indigo pigment and understand its special properties and requirements.

orta indigo flow

orta indigo flow

Images of Orta’s Indigo Flow process. Indigo Flow is the cleanest and most sustainable method of indigo dyeing possible where up to 70% water usage is reduced. A proprietary process of Orta, a clean label dyeing method which will lead our industry into a more sustainable future. 

The Color That Makes Jeans Blue

Indigo is the color that makes jeans blue, it also makes your fingers and sneakers blue if you wear a new dark jeans. That may be unpleasant, but is exactly what makes denim be denim, and those beautiful authentic fades would not arise otherwise.

Denim is yarn-dyed, which means the warp yarn is indigo dyed and the weft yarn stays undyed (at least for basic types of denim). So, the yarn needs to be dyed in an indigo fluid.

The Challenges Of Indigo

The first challenge is that the indigo pigment itself is quite big, as a result, it does not penetrate the core of the yarn. It just stays on the surface and needs to be applied in several layers, to create the dark indigo shade. And because of that, some layers can be removed quite easily, if it is raw – which means unwashed -, you can even remove them with your hands.

The second challenge of indigo starts with producing a fluid dyestuff because indigo will not voluntarily dissolve in water. We need to force it to become water-soluble. That happens with the help of reducing agents, those chemicals start a process, which in the end enables it to dye the yarn in a fluid indigo base. Those chemicals do their job, but they also poison the wastewater. Within this conventional dyeing technique, the yarn goes through up to 15 hot dyeing baths made of a mixture of hot water, indigo, and chemicals. Because the typical blue shade only occurs with the help of oxygen, those baths are open to the top. This technology may work well, but it causes lots of wastewater, is polluted with chemicals, and needs a huge amount of energy to keep those vats at a high temperature.

So, the main problem is the combination of indigo and water to create a fluid dyestuff.

The Good News

Now comes the good news: there is a new technology, which eliminates most of the water use in the process, and together with it also many chemicals. In that waterless dyeing technique, the indigo is applied directly to the yarn in a highly concentrated kind of gel. Therefore the number of vats is reduced to a maximum of three (instead of a max. 15), hence lots of water is saved and polluted wastewater is non-existent. The percentage of saved water slightly varies from company to company because some use a kind of indigo fog in the air, others­­ use foam, but all are avoiding as much water as possible in that dyeing process.

Waterless indigo dyeing is available at many denim suppliers already today, just under different terms. Thanks to those clever chemists and washing experts out there who move the denim business towards a more conscious and protective industry.

orta indigo flow

orta indigo flow

Images of Orta’s Indigo Flow process. Indigo Flow is the cleanest and most sustainable method of indigo dyeing possible where up to 70% water usage is reduced. A proprietary process of Orta, a clean label dyeing method which will lead our industry into a more sustainable future. 

Read also previous episodes:

  • No.1: Sustainable Fibers For Denim, Why Hemp Attracts More And More Attention here.
  • No.2: Recycling in denim, how we could minimize the impact of farming here.

Stay tuned for more sustainable alternatives in the denim world!

Written by Sina Steidinger
Sina Steidinger is a self-employed denim designer and sustainability manager based in Amsterdam. After working for several brands in Germany for the past decade, she recently moved to the Netherlands to be in the heart of the European denim capital and to contribute to the latest developments in sustainable fashion. She is currently designing for Mud Jeans, a Dutch brand, and pioneers in circular denim. As a consultant, she gives workshops and speeches and advices brands on their way to a sustainable future.