Acid Wash Denim Explained

In brief: Acid wash denim has a sharp, marbled, high-contrast finish created by tumbling garments with pumice stones soaked in a bleaching agent such as chlorine or potassium permanganate. The dry stones strip indigo unevenly, leaving bright white blotches against the original blue. Popularised in the 1980s, it is also called marble, moon or snow wash. Despite the name, it is the oxidising bleach, not literal acid, that does the work.

What is acid wash denim?

Acid wash denim is denim with a distinctive marbled, high-contrast appearance, where patches of near-white sit sharply against the original indigo. The look is created by tumbling the garments with pumice stones that have been soaked in a strong oxidising or bleaching agent, commonly chlorine bleach or potassium permanganate. As the dry, chemical-soaked stones tumble against the fabric, they strip indigo aggressively and unevenly wherever they make contact, producing the characteristic mottled, marbled effect. The name is slightly misleading, because it is the oxidising bleach rather than an acid that removes the colour.

How is acid wash made?

The traditional method uses pumice stones soaked in the bleaching solution and then tumbled with the garments in a rotary drum with little or no water, so the chemical acts in concentrated spots rather than evenly across the cloth. That uneven, localised bleaching is what gives acid wash its sharp contrast and marbled pattern, as opposed to the softer, more uniform fading of a standard stonewash. The technique became a defining look of 1980s fashion and is also known as marble wash, moon wash or snow wash.

Acid wash vs stonewash

Both finishes use pumice, but the effect is very different. Stonewashing tumbles plain pumice with the garments to abrade indigo gently and evenly for a soft, faded, vintage look. Acid wash adds a bleaching chemical to the stones, which strips colour far more aggressively and unevenly, creating bright white marbling against the blue. Stonewash is subtle and classic; acid wash is bold and high-contrast, a deliberate statement finish.