Before plucking and after the birds have bled out, the birds are conveyed through a water tank filled with hot, scalding water. Hence the name of the machine: scalder or scalding tank. The water can be heated by heating elements and functions to help loosen the feathers from the skin. This is absolutely vital to achieve a good defeathering result. Blowers inside the tank will create turbulence in the water, meaning the birds are completely immersed and scalded.
Three general scalding settings are:
- soft/semi-scalding at 50-52ºC for 3 minutes
- medium scalding at 54-56ºC for 2,5 minutes
- hard scalding at 58-60ºC for 2 minutes
The higher the scalding temperature, the better feathers are loosened from the follicles. However, it also has the most effect on the skin: the outer skin layer, also called epidermis, will also loosen and will be removed by the plucker. This leads to a lighter skin, which is a product preference in some countries. It is generally not recommended to combine hard scalding with air chilling, because the skin will discolor unfavorably due to dehydration in the air chilling room.
