This is more likely to occur when jeans are washed in hot water or dried on high heat. The heat causes the cotton fibers to tighten up, and if the fabric doesn’t shrink evenly, you’ll see wavy patterns or twisted legs.

2. Tension During Manufacturing

Another reason for post-wash ripples is related to how the denim is made. During the weaving and sewing process, different parts of the jeans are stitched under tension. If the tension isn’t evenly distributed, the fabric may look smooth at first but once washed, those areas begin to shift and buckle, creating ripples or twisting.

Cheaper jeans or those made with less attention to construction may be more prone to this issue. Even expensive jeans, though, can develop ripples if they’re made with stretch denim or inconsistent stitching.

3. Stretch Denim and Elastane Issues

For comfort and stretch