Those weird ripples and puckering on your jeans after washing aren’t random. Most modern jeans are made from a cotton and stretch fiber blend—elastane or spandex—and heat is the main culprit. Hot water or high dryer heat damages elastane, causing the surrounding denim to warp. Once that distortion happens, it’s usually permanent. No amount of ironing will fix broken elastic. The fabric is physically changed.

Overwashing also plays a role. Washing jeans too frequently weakens fibers and leads to uneven shrinkage, especially in stretch denim. Movement during washing adds to the problem. Jeans can twist, stretch, and bunch up—particularly in an overloaded machine—creating uneven tension. That tension shows up as visible waves or puckering across the fabric. Water absorption isn’t even either. Denim soaks unevenly, and stretch fabrics expand more in some areas. As they dry, those sections shrink at different rates.

Crowding the washer or dryer makes everything worse. Jeans can dry while twisted or folded, setting unwanted creases and ripples into the fabric. The result is a pair of jeans that looks worn out even if you’ve only worn them a few times. The irony? You’re trying to clean them, but you’re actually damaging them. Less is more. Cold water is your friend. Heat is not.

To prevent this, wash jeans in cold water. Avoid high heat entirely. Air drying is ideal—just hang them up. If you must use a dryer, choose low heat and remove them while slightly damp. Turn jeans inside out. Use a gentle cycle. Don’t overload the machine. And most importantly, don’t wash jeans after every wear. Let them breathe. They’ll last longer, look better, and stop developing those weird ripples that make you wonder what went wrong. Nothing went wrong. You just cooked the elastic. Now you know.