TENCEL™ Lyocell and BAMBOO Viscose are two similar clothing materials. Both have comparable properties in terms of their transformation processes, softness, drapability and mostly their assumed environmental qualities.
Both fall into the category of man made cellulosic fibres. Cotton, linen (flax) and hemp are natural cellulosic fibres. Viscose and lyocell are artificially made with cellulose extracted from trees.
As we are trying to move towards a sustainable (sustainability is like happiness, you never quite achieve it, but you can move closer to it) fashion industry, which one should we choose ?
Eucalyptus vs Bamboo
We can all agree that bamboo can be sustainably grown. It absorbs more CO2 per acre than any other forest. It grows like a weed (without any chemical inputs)... it is a weed.
TENCEL™ Lyocell is made either with eucalyptus grown in plantations or responsibly sourced wood. The eucalyptus is said to be grown on arid land, on which it's impossible to plant other crops.
Bamboo seems to be the best choice as it sequesters more CO2 (12 to 17 tonnes/hectare annually). Although eucalyptus wouldn't be too far behind (around 10 tonnes/hectare). These numbers vary a lot depending on many variables.
Lyocell vs Viscose
What really sets those fibres apart is their transformation processes.
Viscose inherently needs hazardous chemical inputs : sodium hydroxide, sulfuric acid and carbon disulfide.
Look at the ingredients of your soap, you'll find sodium hydroxide. If you are careful with it, it's not dangerous.
Sulfuric acid is similar, maybe just a bit more hazardous.
The real problem is carbon disulfide which can be very hazardous for factory workers and people living near the plant. Also hydrogen sulfide is a by-product of the chemical reaction.
The viscose process can be done in a responsible manner by treating the water used, capturing gas emissions, carefully monitoring chemical inputs and outputs. 10% of the world's viscose in transformed in Europe with high EU BAT environmental standards.
But bamboo viscose (or rayon, viscose = rayon, same thing) exclusively comes from China where environmental standards aren't as high.
On the other hand, lyocell is simpler and requires using a biodegradable non-hazardous solvent called NMMO.
No certification exists to assess (well maybe STeP by OEKO-TEX®) whether a bamboo viscose has been produced responsibly (EU BAT Standard) or not. As a consumer, as a brand I can't know for sure.
There is a clear benefit of choosing lyocell over viscose: being sure there's no negative impact linked to hazardous chemicals.
Confidence in the brand
TENCEL™ is a trademark of Lenzing AG. That is literally what the branding guidelines ask you to say. And I get why.
TENCEL™ is a brand of lyocell and it only comes from one source, one company.
It's made in a closed loop production process that recycles process water and reuses the solvent at a recovery rate of more than 99%.
According to Canopy's Hot Button Report, Lenzing is a leader in responsible wood sourcing.
Lenzing Lyocell won the technology award for sustainable development back in 2000.
Bamboo viscose comes from multiple sources, different companies, manufacturers. It's very hard to trace. I don't know where they stand on the Canopy's Hot Button Report or if they have closed loop processes.
Bamboo viscose fibres are often certified Oeko-Tex standard 100 (basically means that the end product fibre was tested in a lab for hazardous chemicals) which is very misleading for the consumer as it doesn't mean anything in terms of responsible viscose production.
TENCEL™ Lyocell scores another point.
Bamboo viscose lasts longer than TENCEL™ Lyocell. I've had a lot of underwear in TENCEL™ Lyocell wear out and very few in bamboo viscose over the same period of time.
I know there are different qualities of TENCEL™ Lyocell, it's just my personal experience.
I've been looking for the best of both worlds : bamboo lyocell. I know it exists in China but I haven't been able to find fabrics distributed locally.
Written by Ugo Dutil :
I grew up in the ecovillage Cite Ecologique. I like this way of life that values human relationships, sustainable development and personal growth. I’ve been working with Respecterre since 2013. I'm fascinated by hemp, minimalism, slow fashion, local supply chains, zero waste, viscose production and transparency.