An understanding of the basics of cotton yarn in textile production.
Cotton fiber is a thread-like substance, called “Staple". Grown in warm drier climates, cotton requires 4-5 months of 60°F - 86°F weather. Although the textile industry has migrated east, The U.S. cotton industry still thrives, ranking third behind China and India.
The length of staples determines the quality of cotton. The higher the length, the better the cotton is. Staple length can vary from .375” to 2.25” depending on variety and growing location (temperature, fertility, and water stress all affect the length of the staple).
Types of Cotton
There are four main varieties of cotton:
Sea Island Cotton - it is the best quality of cotton in the world and it has the longest staple of 2.25”. Sea Island Cotton is mainly grown in South Carolina, Georgia, Florida and islands off the coast of these states. Sea Island Cotton is frost-sensitive and thrives in tropical areas with high humidity.
Pima Cotton – is related to Sea Island and Egyptian cotton adapted to grow in more arid climates through a partnership between the U.S. Department of Agriculture and Pima Tribe Native Americans. USDA named the cotton after the Pima Tribe to honor the collaboration.
U.S. Cotton – has 3rd largest staple length and is grown in U.S. other than the states where Sea Island cotton grows. The staple length varies but may reach maximum 1.5”
Asian Cotton – is grown in Asia like India, Pakistan, Japan, and China. The most common variety of cotton with a maximum staple length of 1.125”.
The thickness of the cotton staple is the other determinant of cotton quality. Finer longer staples yield higher quality yarn as slim long staples can be spun together to create finer, stronger cloth.
Preparing for Yarn Spinning
You must prepare the staples for spinning into yarn by removing foreign objects, separating usable staples, and aligning the remaining staples. The resultant "sliver" is achieved through a process of combing or carding.
Higher quality staples are 'combed' through a series of metal teeth that lay the staples parallel to each other. This is a more expensive process as combing cotton will save only the finer, long staples for processing.
Shorter staple cotton must be carded (to survive the process). Cards with wire teeth are used to separate the staples from the detritus however they are not laid parallel.
If you take 1 strand of yarn of and 840 YDS (1 YD = 0.9144 Meter) of same and if this 840 yds weigh 1 lb, then we can call this 1s yarn. While seemingly a random number, 840 yards is the distance that 1s cotton occupies to weigh 1Bb, therefore all other measurements must use 840 yards and 1Lb as controls.
For example, take 2 strands of yarn each 840 yds in length and both together weigh 1lb, then we call this 2s yarn. Twice the yarn weighs the same. As mentioned, the finer the yarn, the better quality the textile.
Theoretically in the textile industry, one can make yarn from 4 count to 120 count. The higher the number of counts the finer the yarn is. Normally in towel business we work with 10S up to 30s with 12s and 16s being the most common. Higher numbers are usually used for making finer fabrics.
Single Vs Double Yarn
Single yarns are twisted using a mechanical process to make it stronger.
For example if 2 10s yarns are twisted together it will make a 10/2 yarn. You can use the fraction to determine what thickness it would be as a single yarn 10/2 = 5/1. However, the strength of the yarn will be higher as the cotton is wound together (similar to the internal suspension cables in a bridge). The yarn will also feel finer because it uses longer staple cotton.
The ground consists of warp (purple) and weft (blue) which provide structure and strength. Cotton pile (yellow) absorbs moisture and gives the towel body and softness. Pile yarn is what people feel when using a towel to dry their body.
So single and finer count yarn is used in the pile whereas weft and warp yarn are used to make the base and weave strong. Weft is a single yarn whereas ground yarn is mostly a double yarn for better strength.
Sometimes blended (50/50 Cotton/Poly) yarn us used in the ground for institutional towels to fortify the towel's strength so that it can be laundered more often (thus extending the lifecycle and lowering the linen budget).
A well balanced institutional towel will follow similar ratios to balance lifecycle and cost.
Pile Yarn 55-60% 10s - 24s yarn
Weft Yarn 22-18% 10s - 20s cotton yarn
Warp Yarn 23-22% -10/2 - 20/2 cotton yarn (the warp must be doubled for strength).
Towels vs Other Textiles
In terry towel production coarser yarn (count) is used. Whereas other textiles like bed sheets and clothing use a higher yarn count - 50/1, 60/1 and even 100/1 depending on what kind of the desired fabric quality.
Retail towels use 100% cotton yarn special fibers like Modal & Bamboo fiber may be incorporated to give the towel a softer, more plush look and feel. Special fibers are more costly which makes them unsuitable for institutional textile use.
Most retailers use a higher yarn, better quality yarn count to make their towels softer (E.g. 30s Pima Cotton).