In contrast to the soft crust they form on your midsection if you overindulge, the combination of beer, fat and flour forms the lightest, airiest crusts on fried foods this side of tempura. Although beer-battered foods typically need the deep fryer to reach golden-brown goodness, you can recreate the deep-fat-frying results in just a little oil if you modify the cooking technique a bit.
Deep-Frying vs. Pan-Frying
All frying methods have one thing in common: hot fat. Although the amount of fat varies — deep-frying requires enough oil to submerge food completely, whereas pan-frying requires enough to reach halfway up the side of food — they both cook food by first dehydrating its surface so a crust can form. The crust prevents the food from absorbing oil while transferring heat to the interior, where it gelatinizes starches, denatures proteins and softens fibers — or cooks. Frying is actually a dry-heat cooking method that uses a fluid cooking medium. When pan-frying beer-battered foods, you need a cold, stiff batter that crusts over as soon as it hits the oil to prevent it from sliding off.
Beer’s insolubility at high temperatures makes it the go-to liquid for batter bases. Unlike solids, gasses dissolve more readily in cold temperatures than hot. When beer batter comes in contact with hot oil, the carbon dioxide creates froth that causes the egg and flour mixture to expand, forming a light, crisp, airy crust. Alcohol also plays an important part in giving beer-battered foods their crispy shells. Since alcohol evaporates faster then other batter bases, like water and milk, it cooks faster, lessening the chances of overcooking the battered ingredient. Basic beer batter consists of 1 cup each flour and beer to 1 egg. Since food isn’t completely submerged in oil when pan-frying, you want beer batter a little stiffer than when deep-frying to help it hold its shape. Use 1.25 cups of flour to each cup of beer when making a batter for pan-frying.
An oil temperature between 350 and 375 degrees Fahrenheit is crucial to successful frying. You need oil hot enough to cook the food through before the crust overcooks. This isn’t a problem with deep-frying, since you can check the temperature with a probe thermometer and adjust the heat as needed to stay between 350 and 375 F. But with pan-frying, the oil doesn’t reach high enough on the probe to check, leaving you with two options: use an infrared thermometer, which you probably don’t have, or a 1-inch cube of white bread. A 1-inch cube of white bread fries to golden brown in 60 seconds when the oil measures between 350 and 375 F. Heat 1 to 1 1/2 inches of oil over medium-high heat for about five minutes, and drop a 1-inch cube of white bread in it. Adjust the heat as needed so the bread turns golden brown in exactly 60 seconds.
Chill the beer batter to refrigerator temperature while the oil heats in a wok, cast-iron skillet or heavy bottomed pan. Peanut, canola and sunflower work best with beer-battered foods. Dredge the ingredient in flour and dip it in the beer batter. Lay the battered food in the oil and spoon or ladle hot oil over it for about 30 seconds to set the beer batter on top. Cook beer-battered fish about four or five minutes, and cook vegetables until golden brown. Turn the food over with a slotted spatula or spoon halfway through cooking.
References and ResourcesFine Cooking: The Science of Frying
Scientific American: Beer Batter is Better