Apple Cider Vinegar for Meringue

Our answer

An acid, such as a vinegar, can be added to a meringue mixture to help create a more stable foam when the meringue is mixed. In scientific terms the acid helps to denature, or break down, the coils of amino acids in the egg white's proteins so that they become long strands instead. When these strands are whisked they join together around the bubbles of air and make a foam which can then have sugar added to make meringue.

White wine vinegar is quite common as it doesn't have a particularly intrusive taste, we feel that red wine vinegar and particularly balsamic vinegar are not ideal as they will start to affect the taste of the meringue. Apple Cider Vinegar is also good as it is similar to white wine vinegar and won't add too much flavour to the meringue, or you could also use lemon juice. Powdered cream of tartar is also an option but you will only need half the quantity of the liquid acids - for example, if the recipe says 1 teaspoon of vinegar then use 1/2 teaspoon of cream of tartar.