Are all denim blue jeans made of 100% cotton is a very common question. The correct answer is yes if they are made out of denim. Many manufactures of blue jeans use the name as a descriptive selling device but not necessarily use denim material for the construction of their pants. These are not true blue jeans since all true blue jeans are made of denim, and by definition, denim is 100% cotton.
Denim is a material made from 100% cotton. This is a cotton thread that is used to make a particular weave. It has warped threads in which a weft thread is placed under. This forms the traditional diagonal ribbing on the surface of the material.
The process of dying the fabric is also different than most other weaves. Only the warp threads are dyed using indigo. The weft threads are left in the natural color of white. This is why a true set of blue jeans is blue on the outside but has white on the interior of the pants or clothing item made from it.
With this type of dying and thread pattern that is used for the creation of the denim fabric, fading of the material is a natural occurrence. Because the threads of the weave are 100% cotton, the material will also have a fluffiness to it. The longer it is worn and after repeated washings, the fluff part of the thread will be more pronounced. This is where the comfort level that blue jeans are famous for originates.
If the blue jeans you are looking at or own does not have this type of thread pattern or weave in which some white can be seen, but the tag on it says it is 100% cotton, then the weave might be called the cotton duck. In this weave all of the threads are dyed and pants made from this material are not definable true blue jeans in the strictest sense.
The denim weave is one of the strongest and longest lasting textiles that cotton is made into. Because of this strength and longevity of the material, it was originally made for working cloths. Yes the original purpose of denim and the blue jean was to be worn by men when they are performing physical labor and needed a breathable and durable set of pants that would not easily be torn or wear out.
Its popularity in Pop culture is based on denims ability to fade along with the high level of comfort the wearer has next to their skin. Because of this, popularity of blue jeans has risen. Then there are also the designer blue jeans which are made out of the same denim material that is 100% cotton, and sometimes combined with spandex to make them more comfortable when fitting more snugly.
Cotton shrinks when washed in hot water. This process also helps the dye to be washed out to give that faded look. If the set of blue jeans you have stretches to conform to your body shape and are tighter, especially in the legs, then spandex might be present in the weave and they are not true denim blue jeans.