When frying food in oil, you are likely to notice a foam forming on the surface. But what causes this phenomenon and why does it happen? Let’s find out the reason behind this curious occurrence in the kitchen.
Moisture in food
First of all, it is important to know that oil foams during the frying process mainly due to the presence of water in the food being cooked.
When food is introduced into the hot oil, the moisture it contains evaporates rapidly. This moisture, in the form of steam, rises to the surface of the oil and turns into small air bubbles.
These air bubbles combine with other elements present in the food, such as starch and proteins, and together with impurities that may be in the oil, contribute to the formation of foam.
Reused oil
The condition of the oil, that is whether it is new or reused, must also be taken into account, as this can also affect the amount of foam formed during frying.
The more times the oil is reused, the more viscous it becomes and the more moisture it retains, causing more foam to form. If this happens, it may be a clear sign that it is necessary to filter the oil to clean impurities or residues left from other foods or to replace the oil with a new one.
Excessive quantity and temperatures
Another reason that can cause the oil to foam is the use of an excessive amount in the frying vessel, especially when using a deep fryer. These devices usually have a mark indicating the recommended minimum and maximum oil level, so it is important to make sure that the correct amount is used.
In addition, it is crucial to control the temperature of the oil when cooking food. Sometimes, when there is an excess of oil in relation to the amount of food, the temperature contrast can lead to foaming and the oil overflowing from the pan.
To minimize foaming, it is advisable to dry the food thoroughly before frying, use clean oil and control both the quantity and temperature of the oil at each frying.
