Stonewashing Explained

In brief: Stonewashing tumbles denim garments with pumice stones, traditionally around 250 pounds of pumice per 100 pounds of garments, for 1 to 6 hours in rotary drums. The stones abrade indigo from the surface while ring-dyed yarn cores stay white, creating faded contrast and a softer feel. Modern enzyme washing, or biostoning, uses cellulase enzymes to achieve a similar look with less machine wear.

What is stonewashing?

Stonewashing is a finishing process that gives denim a faded, vintage appearance and a softer hand-feel. In the traditional method, finished garments are tumbled with natural pumice stones, typically around 250 pounds of pumice per 100 pounds of garments, for anywhere between 1 and 6 hours in large rotary drum machines. The result is a worn-in look that would otherwise take months of wear to develop. A modern alternative, enzyme washing or biostoning, uses cellulase enzymes derived from the Trichoderma reesei fungus to soften and fade the fabric with far less mechanical aggression.

How does stonewashing create that vintage look?

The pumice stones physically abrade the surface of the yarns, knocking indigo dye particles off the exposed areas while the ring-dyed yarn cores beneath remain white. That contrast between abraded surface and white core is what reads as fading. Because the abrasion concentrates at seams, pocket edges and other high points, stonewashing produces localised, authentic-looking wear that fabric treatments alone cannot replicate.

What is the difference between stone wash and enzyme wash?

Stone washing uses natural pumice tumbled with the garments. It creates pronounced, uneven abrasion and the most dramatic distressing, but it is harsh on machinery and generates pumice waste and grit. Enzyme washing, also called biostoning, uses cellulase enzymes to break down surface fibres for softness and fading. It achieves a similar aesthetic with reduced environmental impact and far less wear on machines, which is why it has largely replaced traditional stonewashing in modern manufacturing. Many washes today combine a little of both for a balance of character and consistency.