How do you like your air?: Swetha Sivakumar on the vital, invisible ingredient

It is air that links colas and cappuccinos, idlis and soan papdi. In this week's Sound Bites, Sivakumar tracks how pop and fizz can alter flavour.

There’s one ingredient we rarely think of, when cooking; possibly because it is largely invisible. It’s one that makes a critical difference nonetheless: Air.

In food, air usually takes the form of foam, which is the dispersion of gas bubbles in a liquid. A bubble wall is essentially an extremely thin layer of that liquid; the thin layer supports a volume of air inside that can be about a thousand times larger.

Bubbles can play a key role in the