Deep Frying Techniques

Deep frying is a cooking method whereby food is submerged in hot oil or fat. It is one of the fastest possible methods of cooking small, tender cuts of fish and meat. It is also suitable for dough mixtures such as fritters and doughnuts and many vegetables, such as onion and potatoes.

If carried out properly, deep frying will not make food excessively greasy, as the moisture in the food will repel the oil. As long as the oil is hot enough and the food is not immersed for too long, the oil penetration will be limited to the outer surface layer and none will actually reach the centre the food. The correct frying temperature depends on the thickness and type of food, but in most cases it lies between 175 and 190°C (345- 375°F).

Before they are fried, many foods are given a coating of flour, crumbs or batter to protect them from the high temperatures of the fat. This also seals in their juices, which helps to produce a crisp outside coating and a moist and tender centre.

Some foods, such as crisps, do not need any coating as they remain in the oil for a very limited amount of time. Chips are also uncoated; they are initially fried at a relatively low temperature to cook them through, and then given a second frying at a higher temperature to brown them.

Using a Deep-Fryer

1. Checking the Temperature

Always check the temperature of the oil before using. If the deep-fryer is not thermostatically controlled, drop a crumb or cube of bread into the oil and time how long it takes to brown:

  • 60 seconds - the oil is about 180°C/360°F and suitable for gentle frying
  • 40 seconds - the oil is about 190°C/ 375°F and moderately hot
  • 20 seconds - the oil is about 195°C/385°F and very hot
  • 10 seconds - the oil is dangerously hot and should be cooled down

You can cool oil down by turning off the heat and frying several slices of bread.

2. Cooking

Always cook in small amounts; adding too many pieces of food at once will lower the temperature of the fat. This will mean that the coating will not form a crisp crust, and the food will lose its juices and absorb fat.

This is particularly important when frying frozen food such as chips or fish fingers. Do not make the mistake of using very hot fat to offset the cooling temperature of the frozen food; a relatively cool fat temperature (180°C/360°F) is needed to cook frozen items to ensure that the centre is thawed and cooked before the coating browns.

Drain any cooked food well, and then place on kitchen paper to mop up any excess oil. Keep any food that is not to be served straight away in a warm oven with the door ajar - covering or enclosing the food will make it soggy.

3. Cleaning the Oil

After the fat has cooled, it should be filtered through muslin or a coffee filter paper to remove any food particles. The oil should be changed as soon as it becomes dark, odorous or cloudy.