Fiber Content Determines Shrinkage
Denim fabric is unique in that there may be a variety of weaves such as the right and left hand twills, cross hatch and broken twills. In addition there are combinations of fibers used when weaving the denim fabric.
For example, a denim fabric that is developed when creating a diagonal weave using a cotton fiber in one direction (length) and a nylon fiber in the other direction (width) will overall have less shrinkage than the denim fabric created using cotton in both directions.
Does shrinkage occur in the Washer or the Dryer?
Cotton and other natural fibers have more of a tendency to shrink than man made fibers such as nylon and polyesters. Blended fabrics will shrink depending upon the amount of natural fibers in the finished cloth. Denim fabric with a looser weave will shrink more than one with a tighter weave.
Denim will shrink more when washed in hot water and when put in a hot dryer. Shrinkage will occur in both washer and dryer with temperature being the determining factor.You will also lose more of the dye in the fabric when washed in higher temperatures. On the other hand to keep shrinkage down wash in cooler temperatures and either hang to dry or use a low heat setting to keep shrinkage to a minimum.
The beauty of denim is the diagonal weave where it expands to your body shape and movement with wear and returns to the garments original shape once laundered.
Today there are more denim fabrics produced with blended fibers and the percentage of the blend will vary according to the desired characteristics of the final fabrics. Using blended fibers when developing fabric will allow for greater strength and durability of the finished fabric or can allow for desired stretch and recovery of the fabric. Denim jeans made from all cotton have less give and recovery than those with a nylon or polyester blend.
Using blended fibers has allowed for a more successful fit when you have a single size that needs to accommodate many body types. This has helped to increase the popularity of denim jeans to soar even higher in the past 1-2 decades. Try wearing a customized sports jacket with a pair of stretch jeans and you will find yourself very comfortable when travelling or for leisure wear.