An age-old grading system is used to ensure that the quality of wool fabric is accurately categorized—and valued. The finest worsted wools are called “super wools” or “choice wool.” Carded wools are called “woolens.” When the grading system for worsted wool began in England, it applied only to 100% pure raw wool, but now covers wool blends that incorporate other natural fibers, such as cashmere, mohair, or alpaca. While the USDA monitors wool grading in the U.S., The British Wool Textile Export Corporation introduced a code of practice concerning the description of wool quality in the 1990s to clear up confusion in the marketplace caused by companies describing the same qualities of wool in different ways.
The main benefit to consumers is consistent rating of the quality of wool fiber contained in cloths woven in the United Kingdom. For more than a century cloth woven in the United Kingdom has been acknowledged among the world’s finest.
The craft of cloth making has been handed down from generation to generation culminating in today’s superfine fabrics. Today’s fabrics combine all of the craft’s tradition with cutting edge technological advances in animal husbandry , wool growing, combing and spinning practices.
The “Super” number refers to the length of wool yarn produced from one pound of raw wool, so the longer and thinner the fibers, the higher the number. (The “S” or “super” can also be left off, as the true measurement of grade is the number). These wool fibers are not only thinner than others, but are also longer than thicker, fuzzier wool fibers, so super wools create longer skeins of thinner yarn. “Super” numbers start with the 80s and increase by 10, to range up to 210 for extremely high quality wool. Super 80s are up to 19.50 microns in diameter, while Super 210s are no more than 13.00 microns wide.
The long, thin fibers in Super 200s or Super 210s create a far finer and silkier cloth than can be made from coarser wools, but wool with lower Super numbers will likely keep you warmer in cool weather. When you’re crafting a suit, it’s important to know when and where you intend to wear your suit, and choose your wool accordingly. The higher wool grades, while wonderful for many circumstances, are not always best for high performance situations, heavy wear, or frequent travel.
One micron is equal to one thousandth of a millimeter and the micron count refers to the diameter of the individual fibers from which the yard is spun—not to be confused with the thickness or count of the yard itself. Once spun into yarn, any grade of wool could be woven into summer or winter weight fabrics. The finer the wool fiber, the smaller the micron count. The smaller the micron count, the rarer the wool and therefore the more expensive the cloth.