Frying is a cooking technique that has been used for centuries. Sautéing, stir-frying, pan frying and deep frying all operate on the same principles -- what differentiates them is how much fat is used in cooking. It can range from a very thin layer (sautéing and stir-frying) to enough to fully submerge an entire piece of food (deep frying). The biggest benefit to frying is speed. Fat is much better at transferring heat than either air or water, so frying cooks considerably faster than baking or boiling. Plus, the fat imparts a crispy crust and a richness and depth of flavor that is, to many folks, irresistible. But there's one major drawback to frying: health concerns that come from eating fatty foods. Regardless of how healthy the food was before it went into the deep fryer (in case you're thinking of deep frying spinach), it's going to come out with five to 40 percent absorbed oil by weight. That's a major drawback for anyone who's watching their fat or calorie intake. For healthy people who don't need to worry as much, however, the occasional fried treat is not a problem. To better understand these often defamed snacks and treats (and sometimes whole turkeys), let's dive into the science of how simple hot oil transforms everyday foods into sinful delights!
When Food First Hits Oil
When Food Is Done Cooking
Preventing Greasiness and Sogginess
Excessive greasiness can also be caused by poor drainage or by sitting for too long before serving. Ironically, batch frying, which is supposed to alleviate greasiness, can be the very reason fried foods have to sit too long before serving. The solution once again is to keep that steam flowing! That usually means immediately transferring your food to a warm (200 degrees F) oven until you're ready to serve. Keeping your food steaming hot slows the oil's migration into your food while at the same time preventing another unpleasant end: sogginess. Sogginess is a particularly common problem with fried foods that have been coated with a batter or breading. When food starts to cool, the moisture in the space between the crust and the food turns into water droplets instead of steam. This can make the crust soggy from the inside out and ruin your once crispy crust.
A Quick Look at Batters and Breadings
Batters result in a smooth, crispy and often delicate crust. Batter recipes vary widely, so results differ depending on ingredients. For example, high gluten flours result in a chewy (some might say tough) crust, whereas gluten-free flours (like rice flour) result in a paper-thin ultra-crispy crust (think: Korean fried chicken). Adding eggs or sugar to a batter will result in a darker crust, which may or may not be desirable. Batter coatings are smoother and have less surface area than most breaded coatings, so they tend to absorb less cooking oil. They also tend to offer the most protection for delicate foods, which is why fish are commonly battered before frying (think: fish and chips).
Breadings result in a crispy, crunchy, textured crust. Breaded coatings can range from fine breadcrumbs (think: Chick-fil-A), to large, extra-crispy breadings (think: KFC, Popeye's, Japanese tempura). Fine breadcrumbs tend to absorb less oil then the extra-crispy style, since they provide less surface area for oil to soak into, but they are prone to sogginess. Extra-crispy style breadings are usually achieved by incorporating large, already crispy particles, such as Panko-style breadcrumbs or cereal, such as cornflakes.
Although batters and breadings are delicious, some foods don't require a coating at all. Starchy foods, like potatoes, plantains and yucca root will form their own natural protective skin once they're dunked in the fryer. This makes prep easy and accessible for the home cook. Take a look at the simple fried plantain salad I made while on vacation a few weeks ago. It was quick and easy to throw together, and it's a great starter recipe for frying novices!
Fried Plantain Salad
1 plantain, mostly brown
Soybean, vegetable, corn, peanut, or canola oil, enough to cover
Salt and pepper to taste
1 tomato, diced
Lime juice, to taste
1. Heat oil to 375F in a skillet, or, if you don't have a thermometer that will go that high, check to see if your oil is sizzling hot by sticking the end of a wooden spoon in the oil. If it bubbles, so will your plantains!
2. Peel plantain and slice into coin shapes, about ¼ inch thick. Add them to the hot oil. They'll float, so you may need to flip them after a few minutes. Fry until the bubbling has slowed and they have a nice rich, golden brown color.
3. Drain onto a paper towel and season with salt and pepper immediately. Toss in a bowl with diced tomato and a bit of lime juice, to taste. Add additional salt and pepper if necessary. Serve immediately.
1. Owen R. Fennema, editor, Food Chemistry, 2nd Edition (New York: Marcel Dekker, Inc, 1985), 210-211.
2. Amy Brown, Understanding Food: Principles and Preparation, 2nd Edition (Belmont: Wadsworth/Thomson Learning, 2004), 131.