We recommend that you only dye woollen clothing (e.g. sweaters or cardigans) in a pot. This way, you can reach the required 60°C dye temperature while avoiding the fluctuations in temperature that cause wool to felt.
However, please note: when dyeing wool, shrinkage or felting cannot be ruled out entirely (as when washing wool). Luxury wools such as cashmere, mohair, merino, or angora cannot be dyed.
Background information
Wool can only be dyed an intense colour shade if the dye temperature is 60°C. In the textile industry, wool is often treated at very high temperatures.
This is because high temperatures do not cause wool to felt, as is often assumed. Felting occurs as a result of thermal shock—if the dye bath is heated up or cooled down too quickly. This makes the wool contract and mat together.
Thermal shock may occur when the water is heated in the washing machine or during the rinse cycle. Therefore, it is only possible to dye woollen textiles in a pot.
