Overcrowding the frying pan

Maintaining an even temperature throughout the cooking process is essential for successful deep-frying, which means that overcrowding the pan is your worst enemy. The reason for this is simple physics. Adding cold food to hot oil will naturally lower the temperature, similar to adding ice cubes to a hot drink. The lower the temperature of the oil, the longer it takes to return to its ideal temperature, and the greater your chances of getting greasy instead of crispy food.

As a result, according to CulinaryLore, it's critical to fry in small batches. This prevents the oil temperature from falling too low, allowing you to maintain the ideal temperature for each batch. If you're frying a large quantity of food and are concerned about the first batches becoming cold before you've finished, The Spruce Eats recommends placing any cooked food on a cooling rack set over a baking sheet and placing it in a low or warm oven until you've finished frying the rest.