Frying batter is made with cold, carbonated water because cold water keeps the flour’s gluten loose, helping the batter form a thin, brittle crust instead of a tough one in the oil; bubbles in the carbonated water expand in the oil, making the crust light and lacy. Mix the batter only a little, leave some lumps, and use it right away. Japanese tempura is made according to this principle.
As the proteins in flour meet water and are mixed, they form an elastic network called gluten. That network is desirable in bread, but not in frying batter; a gluten-rich batter creates a tough, chewy, oil-absorbing crust. Cold water slows the formation of this network. That is why the water for frying batter should come straight from the refrigerator or have a few ice cubes added; you can also chill the flour in the freezer for a while before using it. The colder the batter, the thinner and more brittle the crust.
Mixing is kept brief for the same reason. Stir the frying batter a few times with a whisk or fork, then stop when it flows off the spoon; small lumps of flour are not a flaw. Long, vigorous mixing develops gluten and makes the batter rubbery. Traditionally, tempura batter is mixed with chopsticks using only a few strokes. Do not prepare the batter ahead and let it sit; gluten develops in batter as it rests, and the bubbles escape from carbonated water.
The bubbles are what carbonated water contributes. Batter made with plain seltzer or sparkling mineral water contains countless tiny gas bubbles. When the batter hits hot oil, the bubbles expand with the heat, opening tiny spaces inside it and giving the crust a light, airy, lacy structure. A little baking powder produces a similar effect. Cold carbonated water combines two benefits: it slows gluten development and keeps the gas dissolved in the water longer.
The large temperature difference between cold batter and the oil also helps make the crust crisp. When ice-cold batter hits oil at 170–190°C / 340–375°F, the surface sets immediately, leaving little time for oil to penetrate. If the batter is warm, the crust forms more slowly and absorbs more oil. That is why, when frying a large batch, the bowl of batter is set inside a larger bowl filled with ice and kept cold throughout frying. Pat the food dry before dipping it in the batter, and dust it lightly with flour if you like. Batter will not cling to a wet surface and may slide off into the oil.
Replacing some of the flour with starch makes the crust even thinner. Because cornstarch or potato starch contains no gluten, replacing one-third of the flour with starch makes the crust crispier and lighter in color. Adding egg yolk to the batter enhances its color and flavor but makes the crust a little softer. Frying batter works best for vegetables, shrimp, fish, and thin slices of meat. Lower each battered piece into the oil right away and serve it as soon as it is fried; this crust does not hold well.
Comments (1)
Gazlı suyla yaptığımda kabuğun daha ince olduğunu fark etmiştim ama soğukluğun gluteni gevşetmesi kısmını bilmiyordum.