Cotton: what it is, how it is made, special characteristics and use

Cotton is a natural fiber obtained from the flower of the cotton plant. When spun, it produces a soft and durable yarn that is excellent for dyeing and weaving. The longer the fibers, the higher the quality of the yarn.

Cotton explained

Cotton is the most important raw material for making denim. Most of us know cotton from the soft pads and balls we use to stop bleeding and for make-up.

It is a natural fiber that comes from the cotton plant, an ancient crop that has been cultivated for thousands of years. Cotton used to be a wild plant, but through breeding and genetic help it has evolved to be easier to work with and give better yields.
The cotton boll, the fruit of the cotton plant, yields a fluffy white raw fiber called "lint". This is then used to make jeans. Each cotton boll is the size of a fig and contains about 500,000 fibers.

Cotton is one of the world's most important crops in terms of the usability, economic value and environmental impact of its production. In the denim industry, cotton is undoubtedly the most important raw material.
In the past, denim was made almost exclusively from 100% cotton. Today, consumers want jeans that can be stretched, which means that some kind of polyester-based elastomer is added to the fabric. But even then, the raw material is 98-99 % cotton.

How cotton is produced

The cotton plant needs a lot of sun to grow. It takes about 140 days from sowing to harvesting the dried cotton flowers. The best yields are obtained at latitudes between 45° north and 30° south.

Each plant produces about 300 to 350 grams per season, from up to 100 flower capsules per plant. This means that it takes two plants to produce enough cotton for an average pair of five-pocket jeans.
After harvesting, the raw cotton is ginned at the place of cultivation. This process separates the fibers from the seeds. The cotton is first sucked into pipes that transport it to a dryer to reduce moisture. The cotton is then cleaned to remove all foreign matter.
After ginning, the raw fibers are pressed into bales, each of which weighs about 250 kilos - enough to make denim for about 350 pairs of jeans.

Cotton is now grown on every continent except Antarctica, of course. China, the United States, India and Pakistan are the largest cotton growing countries in the world. But Brazil, Turkey and Australia also contribute their share, and it is getting bigger. If you add them all up, these countries supply most of the cotton that ends up in our jeans.

Characteristics of cotton

Cotton is defined and categorized on the basis of a number of physical properties, including staple length, fineness and maturity, strength and colour.

Staple length

Staple length refers to the length of the fibre and is the most important physical property of cotton. There are different types of cotton with different staple lengths.
Upland cotton from the short staple cotton family is most commonly used to make jeans, and a staple length of one inch is sufficient.
Short staple cotton is generally cheaper and of lower quality. However, since denim is usually made from yarn with a coarse yarn count - the thickness of the yarn - the quality is lower.
However, extra-long staple (ELS) cottons such as Egyptian Giza, Indian Suvin and Chinese Xinjiang can also be used to make denim.

Fineness and maturity

The fineness and maturity of a cotton fiber are also important. The finer and more mature a fibre is, the better the quality of the fiber. These properties are measured in micronaire, the air permeability of compressed cotton. Using cotton with a low micronaire number results in damaged yarn and more waste because it breaks more easily.

Strength

The strength of the fibre is measured as tensile strength. It indicates the maximum load that the fibres can withstand before they break. This, of course, affects the strength of the finished fabric.

Colour

Finally, there is the colour of the fibers that distinguishes one batch of cotton from another. The colour is particularly important when the cotton enters the fabric undyed.

Use of cotton in denim

Why is denim made from cotton? What are the benefits?

Apart from the fact that cotton has been around for hundreds of years, it remains popular because it is comfortable, breathable and durable, and because it looks good when made into fabrics.

To determine what makes one type of cotton better than another, you have to look at the properties of the fibers. The longer the staple, the finer and more mature the fiber, and the stronger it is, the higher the quality.

The quality of cotton also depends on where it is grown, how it is harvested and the seasonal conditions during cultivation.
However, there are some misconceptions about the influence of where cotton is grown on quality. A good example is ELS cotton from Zimbabwe, which is not necessarily of higher quality than similar varieties of cotton grown in countries like the USA.

The difference lies in how it is harvested and processed. In most developed countries, cotton is harvested using large mechanical harvesters. In some developing countries, such as Zimbabwe, cotton is still picked by hand.