By nature, a wool fibre is not smooth but has a scaly surface. These scales can hook together under high friction and rapid temperature changes, causing the wool to shrink and felt. This happens particularly easily in the washing machine. To make wool machine washable, several processes have been devised, all of which boil down to making the fibres smooth, a process called 'descaling'.
This jersey is made machine washable using the so-called plasma technique, also known as Superwash. In this process, the wool fibre is made smooth by a mixture of electrons, ions and free radicals. Superwash is a clean technique allowed within the GOTS certification.
It is important to note that the most common process used to make wool machine washable, known as Hercosett, has serious environmental problems. To make the fibres smooth, this involves first exposing them to a bleaching solution (sodium hypochlorite or sodium hypochlorite) that breaks down the outer layer of the fibre to some extent. In a subsequent treatment, the special Hercosett-125 polymer is placed around it, which is perhaps best compared to a thin layer that reseals the fibre. Finally, a softening agent then goes over it.
Wool made machine washable using the Hercosett process is not eligible for organic certification because of the use of highly polluting and potentially dangerous chemicals such as AOX that can end up in surface water. The high water consumption is also a point of criticism.