Foam is caused by the whey protein inside a drink, which traps little air bubbles.

In other words, there’s nothing to worry about - it just shows there’s high-quality protein in your drink!

Tiny air particles get trapped in liquid when we move bottles around. Proteins are made up of amino acid chains, which get partially loosened during processing.

This makes them start to bind to both water and air, which forms a structure that traps air in the water, leading to quite a stable foam on the top of your drink. It’s quite similar to how your egg foams up when you beat it, and is quite common in any protein products.