Jeans often develop strange ripples, puckering, or wrinkles after washing, and it’s not just bad luck. Modern jeans usually contain a blend of cotton and Lycra (or elastane) for stretch. The problem? Lycra is sensitive to heat.Hot water in the washer or high heat in the dryer can degrade Lycra, causing the surrounding denim to warp. Once this happens, the ripples are permanent.

Overwashing can also weaken fibers. Many people wash their jeans far more than necessary, which speeds up wear and causes uneven shrinkage. Another factor is the movement inside the washing machine.Jeans get twisted, stretched, and contorted, especially if the washer is overloaded. This uneven tension results in waves or puckers in certain areas rather than overall shrinkage.Denim absorbs water unevenly too. Stretchy fabrics swell more in some areas than others, and as they dry, these uneven sections shrink at different rates, leaving the jeans looking distorted.Overcrowding in the washer or dryer makes this worse, as jeans can dry in twisted positions that set unwanted creases.