My meringue turned silver instead of staying white when I was making Mini Pavlovas. Could it be from the aluminum in the wire whisk?
Most meringue mixtures, such as Nigella's Mini Pavlovas (from HOW TO BE A DOMESTIC GODDESS) are a mixture of whisked egg whites and sugar, giving a glossy white meringue. If the meringue has turned slightly silver or pale grey then it is possible this is due to aluminium, though it is very rare for this to happen.
If you have an aluminium whisk then it should be oxidised so that it has a hard surface. But if the whisk has been scratched or damaged then there may be some aluminium coming into contact with the whites. Traces of a double acting baking powder with aluminium in may also have caused the discolouration, though this type of baking powder is also now less popular and there are many aluminium-free brands. We suggest using a stainless steel whisk and wiping the whisk and bowl with a little white wine vinegar before use. This will remove any traces of grease or other ingredients that may be on the whisk and bowl and will help the egg whites to reach a good volume when you whisk them.