Why add soda water to beer batter

batter

Why "soda water", in the sentence above my red heart?

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Seafood Basics: 86 Recipes Illustrated Step by Step (2012) by Abi Fawcett,
Deirdre Rooney.

Best Answer

The carbonation in soda water (or beer...or the use of a whipping siphon) is added so that the batter becomes more "airy", leading to a lighter and crispier final result after frying.