Does cotton shrink in the dryer?
Cotton does shrink, but the process of laundering causes shrinking and not solely the dryer.
Why Does Cotton Shrink?
The process of spinning raw cotton into thread places tension on the cotton fibers causing them to stretch. This tension is also placed on the threads during other finishing processes, such as weaving cotton threads into fabric. ((“What You Need to Know about Cotton and Shrinking.” Homegrown Cotton))
According to A.K. Choudhury, author of “Principles of Textile Finishing,” the tension created by these processes that cause the stretching is reduced during the laundering process. Soap and water both act as lubricants. This, along with the agitating that occurs during washing, causes the cotton fibers to relax and contract to their original length. More commonly known as shrinking. Additionally, the act of wetting the natural fiber swells its interior resulting in external shortening. ((Choudhury, A. K. (2017). Principles of textile finishing. Duxford: Woodhead Publishing.))
How Much Does Cotton Shrink?
The amount of shrinkage that will occur on a cotton garment will depend on many factors making a precise value for a broad range of garments impossible.
According to The Journal of Textile Science and Engineering, these include “fiber type, yarn size and type, construction variables, crimp in yarn, wet processes, finishing procedures, and apparel manufacturing techniques.” ((Khan, M. E. (2020). Optimization of Residual Shrinkage Control of 100% Cotton Woven Fabric Through Sanforization. Journal of Textile Science & Fashion Technology, 6(5). doi:10.33552/jtsft.2020.06.000648))
Cotton Incorporated, the research and promotion company for cotton, conducted an experiment to establish if the heat of the clothes dryer is to blame for shrinkage. (They concluded it’s not, by the way.) The researchers noted that the 100% cotton interlock fabric they used in the experiment shrunk about 20% regardless of whether the garment was dried with heat or without. ((“Clothes: Fear the Dryer No More – – Shrinkage no longer a necessary evil.” Cotton Incorporated.))
The above-mentioned book “Principles of Textile Finishing” mentions a total fabric shrinkage of about 10%. ((Choudhury, A. K. (2017). Principles of textile finishing. Duxford: Woodhead Publishing.))
Does Cotton Shrink Every Time You Wash It?
In many cases, a cotton garment will do most of its shrinking after the first wash. Again, the amount of shrinking for any item will depend on the factors mentioned above. ((Choudhury, A. K. (2017). Principles of textile finishing. Duxford: Woodhead Publishing.))
Buying Cotton Garments That Won’t Shrink
If you want to purchase a cotton item that won’t shrink, look for the Sanforized trademark on the label.
Many cotton fabrics undergo a process called Sanforizing before they are made into garments. With the sanforizing process, fabric is fed into a Sanforizing machine that promotes shrinkage. ((“Sanforizing Machine and Process.” Textile Insight.)) This process reduces shrinkage to less than .75%. ((Choudhury, A. K. (2017). Principles of textile finishing. Duxford: Woodhead Publishing.))
