Ozone wash

Ozone washing is a modern, water-saving bleaching method that has been increasingly replacing classic chlorine and permanganate bleaches since the 2010s. The process runs in a closed drum chamber into which gaseous ozone (O3) is fed. Ozone is an extremely strong oxidiser and breaks down indigo chromophores at the fibre surface into colourless fragments.

The big advantage: the process is practically dry — ozone acts in the gas phase directly on the fibre surface, only little residual moisture in the jeans is needed. Water consumption reduces by up to 80 percent, chemical consumption approaches zero. Unused ozone is broken down in a catalyst at the chamber outlet into harmless oxygen.

Jeanologia (Valencia) was the first to industrialise the process with the G2 ozone system and today supplies all major denim producers. The look ranges from mild brightening to strong vintage bleach — depending on ozone concentration and treatment time. Levi's, Wrangler and Nudie Jeans now use ozone washing widely.