Other Factors

Other factors that affect the stability of meringue include the presence of copper or salt, and the type of whisk used. Whipping in a copper bowl increases meringue stability in much the same way that cream of tartar works; that is, it improves the flexibility of a protein network so that it is stable against overwhipping, folding, piping, and baking. With copper bowls, tiny particles of copper are whipped into the whites each time the whisk hits the bowl. Egg whites whipped in copper have a slight golden color.