Since deep-frying involves submerging food in hot, liquid fat, it might take some time to get used to the idea that it's actually a form of dry-heat cooking.
But if you've ever seen the violent reaction of hot oil to even a tiny drop of water, you know that oil and water are a couple of opposites that want nothing to do with each other. Even though fat can take a liquid form, it really is considered a solid — thus dry heat.
Maintain Constant Temperature
Assuming they've been cooked properly, deep-fried items should actually have very little oil on them. Proper deep-frying technique requires maintaining the oil's temperature between 325°F and 400°F. Most oils will start to smoke at temperatures higher than that.
Sealing In Moisture
Food items to be fried are often dipped in a simple batter, or coated in a crispy breading, to protect and further seal in their natural moisture. Because most foods have some moisture in them, and because oil and water don't mix, the food's natural moisture creates a barrier against the oil surrounding it.
That means that while the heat from the oil cooks the food, the oil itself doesn't permeate the food at all — unless the oil isn't hot enough.
Remember the violent reaction of hot oil to a drop of water? The hotter the oil, the more violently it repels water and other moisture. Only at temperatures below 325°F will the oil start to seep into the food and make it greasy.
Fried Foods, Not Oily Foods
So despite the fact that deep-fried foods have a reputation for being oily or greasy, greasy food is merely a sign of poor cooking technique and not an indictment of deep-frying itself.
Curious to see how much oil deep-fried food absorbs? Try this simple test:
- Measure precisely how much oil you pour into the fryer (or dutch oven) before cooking.
- Measure it again after cooking — but wait for the oil to cool first!
The difference between before and after is how much oil ended up in the food. It might be a lot less than you thought. Draining the item on paper towels before serving will help minimize its oil content even more.
Fry in Small Batches
When deep-frying, keeping the oil hot is critical to producing a quality product. The key is to fry items in small batches, because putting too much food in the oil all at once will lower the oil's temperature.
Another clue that deep-frying is, in fact, a form of dry-heat cooking is the attractive golden-brown color of foods cooked using this method. Only dry-heat cooking methods will produce this characteristic exterior browning. (Also see: What is caramelization?)
And speaking of moisture, because of the way hot oil spatters when water hits it, to be safe you should pat any excess moisture from food items before putting them in the deep-fryer. Of course, this assumes that the item isn't being dipped in batter first!