Sanforized Denim Explained

In brief: Sanforization is a mechanical pre-shrinking process, invented by Sanford Cluett and patented in 1930, that compresses fabric before it is cut and sewn. It limits residual shrinkage to roughly 1 to 3 percent, so Sanforized jeans stay close to their labelled size after washing. Most modern denim is Sanforized, while unsanforized loomstate denim can shrink 7 to 10 percent on the first wash.

What does Sanforized mean?

Sanforized denim has been mechanically pre-shrunk so that it will not shrink significantly once you wash it. The process is named after Sanford Cluett, who developed it at Cluett, Peabody and Co and patented it in 1930. In simple terms, the fabric is dampened, then compressed lengthwise between rollers and a rubber blanket so the yarns are pushed closer together before the cloth is dried in that shortened state. Because the shrinkage has effectively already happened, a Sanforized garment holds its measurements, with residual shrinkage usually limited to around 1 to 3 percent.

Sanforized vs unsanforized denim

The practical difference is sizing. Sanforized denim is true to size and will only shrink a little, so you buy your normal measurements and wear them straight away. Unsanforized, or loomstate, denim has not been pre-shrunk and can shrink 7 to 10 percent on its first wash, which means it usually needs to be sized up or soaked before wear so it settles to fit. Enthusiasts sometimes prefer unsanforized denim for its slightly more dramatic, organic shrink-to-fit character, but Sanforized denim is far more predictable and is what most jeans use today.

Do Sanforized jeans still shrink?

A little. Sanforization reduces shrinkage but does not eliminate it entirely, so expect a small amount on the first hot wash, typically within that 1 to 3 percent range. To keep Sanforized jeans true to size, wash them cold and avoid high-heat tumble drying, which is the main thing that drives any remaining shrinkage in cotton-rich denim.