What is grading of wool?

The end use and value of wool depends on certain qualities of wool such as fineness, length, color, and appearance. These are few of the most important quality factors of wool fibers. The fiber thickness and the amount of debris in the wool determines the wool grade which helps the buyer to determine the correct type and quality of wool.

The average diameter or thickness of the fibers determine the grade of wool. And based on this there are three major grading systems of wool fibers.

• The Blood system or American system:
The American system or the Blood system of grading wool was developed in the early 1800s and is one of the oldest systems. It was developed when the native coarse-wooled sheep were being bred to obtain fine wooled Merino in the early American colonies. This particular system is based on the bloodline or breeding of sheep and is defined by the percentage of Merino blood carried by the sheep. The grade or fiber diameter is expressed as fine, 1/2-blood, 3/8-blood, 1/4-blood, low 1/4-blood, etc.

• The English or the spinning count system:
The English system or the count system of grading wool is a more extensive process. In comparison to the blood system. This system provides narrower ranges and a more exact nomenclature. A measurement called the “spinning count” is used in this system and involves the number of “hanks” of yarn that could be spun from one pound of wool. This system of grading wool provides a numerical designation of fineness. The grades of wool commonly used in the english system are 80s, 70s, 64s, 62s, 60s, 58s, 56s, 54s, 50s, 48s, 46s, 44s, 40s, and 36s.

• The Micron System:
The Micron system of grading wool fibers is the most technical and accurate system of grading. The unit of measure is the micron, which is one-millionth of a meter or 1/25,000 of an inch. Using this system the fineness of wool fibers is expressed as the average fiber diameter as measured by a micrometer. This is the standard system of grading wool fibers in the United States.