Preshrinkage

Preshrinkage refers to the deliberate shrinking of textiles before they are cut and sewn into finished garments or products. The goal is to stabilize fabric dimensions and minimize additional shrinkage during subsequent laundering. Preshrinking is common in cotton fabrics, denim, and wool blends.

Industrial preshrinking methods include sanforization for cotton and denim, which uses controlled mechanical compression with moisture and steam to reduce fabric width and length prior to cutting. Other methods involve prewashing or scouring, tumble drying at high heat, or steam treatment in a controlled cycle. For synthetic fibers, heat-setting or chemical finishing may be used to reduce relaxation shrinkage.

Fabrics labeled as pre-shrunk or sanforized have undergone these processes to limit shrinkage in normal use. Denim historically used sanforization; modern pre-shrunk denim aims for a small, predictable shrinkage rate, often around 1 percent or less, though results can vary with fiber blend and laundering conditions.

Benefits of preshrinking include improved sizing accuracy, more consistent fit across wash cycles, and reduced variation between garments. Limitations include residual shrinkage that may occur after extreme washing, potential changes to fabric hand or texture, and added production costs or environmental considerations associated with the finishing processes.

Labeling and consumer guidance: a "pre-shrunk" designation indicates the fabric has been treated to shrink less than unprocessed fabric. Care instructions for preshrunk fabrics may emphasize cool-water washing and avoidance of high heat to maintain dimensional stability.