Gluten. Solubility. Alcohol. And how to get fluffy tempura (and chicken wings).
The yummiest tempura boasts a light and fluffy but still crispy coat. It gently crumbles instead of being a hard crunch. It almost seems to melt in your mouth, instead of scratching against the roof of it.
But it isn’t easy to get such a perfect piece of tempura coating. Chefs may spend a lifetime getting it right, and in fact, some get worked up trying to get it right.
The secret lies in the batter, and the science of gluten.
The flour we use for making batter is made up of two proteins: gliadin and glutenin. They are not soluble in water. Instead when water is added to flour, the proteins in the flour absorb the water, a process we call hydration. The hydrated proteins interact and form new chemical bonds called cross-links.
As we add more water and mix it with the flour, the number of cross-links grows and forms elastic networks and sheets that we call gluten. These cross-links hold up the batter, giving it structure.
But add too much water or allow the batter to stand for too long (as you are frying the food in batches), and what happens is that more cross-links form. The batter can become heavy. When we fry this batter, it holds up so well that the coating comes out hard; it might be crunchy perhaps but definitely not light and crispy.
The trick, according to America’s Test Kitchen, is to use vodka. Vodka is typically at least 40% alcohol and 60% water. One of the flour’s proteins, gliadin, is soluble in alcohol of such concentration, while the other, glutenin, is not.
This simple difference now means that the two proteins do not interact as readily as before — when we used only water — to form cross-links. Gluten formation is thus inhibited. So when we fry the batter made with vodka, the batter is not heavy, and the tempura coating that results is just right.
Use the same trick for chicken wing recipes (also known as buffalo wings). Wings are yummy when the skin is light and crispy too. Add some vodka and it will work the same science magic on the chicken wings as it does on tempura.
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