'Superwash wool' is a wool that has been treated or processed in a way that allows it to be machine washed. It can also be referred to as 'washable wool'.
Most superwash wool is made in two ways (or a combination of the two). The first is to use a chlorinated acid bath that removes the 'scales' from the fiber. Unfortunately, the use of chlorine also results in the creation of chlorinated compounds, including dioxins, which can be deadly to humans at levels below 1 part per trillion. Because the wastewater from the wool chlorination process contains these toxic chlorinated chemicals , it is not accepted by the majority of water treatment facilities in the United States. Therefore, most chlorinated wool is processed in other countries, including the UK and China, then imported.
The other method is to coat the fiber with polyamide and/or nylon that basically keeps the scales from being able to join together and cause shrinkage. A common polymer used is Hercosett 125; a polyamide-epichlorohydrin whose production and raw materials are suspected to be highly toxic.
When raw wool is made into superwash wool, it's natural characteristics are destroyed. It is contaminated with synthetic chemicals and can no longer be considered a natural fiber. For this reason, you won't find superwash yarns used in any of our patterns or kits.
But for those who enjoy superwash yarns, we have good news. There is a newly emerging line of natural superwash yarns, originally created in Germany by the Schoeller Spinning Group. This new process, referred to as EXP for "EX-Pollution", is a natural process which is being used by yarn producers in Europe and the United States. This new technology makes it possible to purchase natural superwash yarns, without having to worry about toxins! To read more about EXP Superwashing, click here.