Does cotton shrink in the wash?
Cotton does shrink in the wash. In the case of cotton, it’s the agitation that’s the culprit for shrinkage, not heat, so yes, cotton can shrink in the washing machine even on a cold setting.
Manufacturing Process Responsible for Shrinkage
When fabrics are manufactured, they are placed under continuous tensions causing them to stretch—this is especially true of cotton. When these same fabrics are then placed in hot or cold water, the fibers of the fabric begin to relax, releasing the tension that caused the stretching action. This causes the garment to shrink.
The Washing Machine Shrinks Cotton Too
Ah, that big mean dryer that eats defenseless socks and shrinks all of your favorite wardrobe staples. In the case of cotton, it’s the agitation that’s the culprit for shrinkage, not heat. The gentle cycle is best for most cotton garments to reduce the tugging and pulling on the fibers.
Tumbling Shrinks Cotton, not Heat?
With all of those temperature settings on your dryer, which one should you pick that will offer the greatest protection against cotton shrinkage? The general consensus seems to be to choose the lowest heat setting, but an informal study has indicated that this simply isn’t true.
According to Cotton Incorporated, the research, and marketing company representing a portion of the US cotton growers, an informal study demonstrated that it is not the heat of the dryer that is to blame for your cotton garment shrinking, but the tumbling action. The researchers tested this theory by placing a standard load of 100% cotton interlock fabric into a dryer with its heat source removed. It took more than 45 minutes for the load to dry in this manner, but the fabric still shrank more than 20%. They followed up this test load with two additional loads with the dryer temperature set at 150°F followed by 200°F. In both cases, the drying time was faster, but the shrinkage was exactly the same, proving that though heat affects drying time, it does not affect the level of shrinkage. And further, because the initial load used no heat at all, it is actually the tumbling action affecting shrinkage, not the heat.
How to Prevent Cotton Shrinkage at Home
Since agitation is the main culprit when it comes to shrinking cotton garments, your best line of defense is to hand wash them gently. If you don’t have the time or energy to wash your clothes in this manner, the delicate setting on your washing machine is a good second solution.
Cotton Incorporated recommends that for best results, tumble your knitted cotton garments for no more than five minutes to remove the wrinkles, then remove them from the dryer and hang them to dry. There are so many factors that go into creating a garment, including multiple fibers and dyes, be sure to read the care label for the best results.
How to Prevent Cotton Shrinkage Before You Buy
Treatments such as Sanforized® can be added to a garment during manufacturing to help reduce shrinkage. Sanforized® is a trademarked name for Controlled Compressive Shrinkage, where fabrics are pre-shrunk by compressing wet fabric, stretching it through a pressure zone, and drying it. These fabrics are tested for shrinkage before they are made into garments.
Resources
Homegrown Cotton – “What You Need to Know About Cotton Shrinking.”
Cotton Incorporated – “Clothes: Fear the Dryer No More — Shrinkage no longer a necessary evil.”
Heddels – “Sanforization.”
