Researchers Find That Tumbling, Not Heat, Shrinks Cotton

The tumbling action in dryers, and
not drying temperatures as previously believed, causes cotton clothing to shrink by evaporating
moisture from the garment, according to research conducted by Cary, N.C.-based Cotton Incorporated.

Researchers found that when they washed a standard load of 100-percent cotton interlock
fabric and put it in a dryer without a heat source, the fabric shrunk more than 20 percent after 45
minutes of tumbling. Likewise, two other loads put in dryers with temperatures of 150 F and 200 F
had the same amount of shrinkage in a less amount of time – proving that temperature affects drying
time, but not the level of shrinkage.

“These findings show that the preferred method of laundering a knitted cotton garment is to
tumble for no more than five minutes to remove wrinkles, then hang them to dry,” said Don Bailey,
vice president, Textile Research and Implementation, Cotton Incorporated.

December 2005