Known fryers suffer from various drawbacks including, above all, the fact that they require high oil consumption for cooking.
The organoleptic and nutritional properties of a food product cooked in excess oil can deteriorate and eating extremely fatty foods can, in the long term, be harmful to one's health.
Moreover, oil has a non-negligible cost and can cause disposal problems and, especially when it is hot, needs to be treated with extreme caution.
For this reason whoever operates a fryer with large amounts of oil is often tempted not to get rid of the oil, leaving it in the fryer to use it many times over thereafter, once again to the detriment of the wholesomeness of the food product thus prepared.