Average of this power multiplicative factor was about 13 (seeTable1for details), i.e. during drying without power control, the final power density is 13 times higher than the initial power density due to the fact that at fixed output power at the end of drying, the final mass is equal to 1/13 of the initial mass. This specific power increase at the end of drying could lead to product charring and make the final quality unacceptable.