If, despite all your whisking, your meringue mixture still seems runny and flat and is stubbornly refusing to stiffen up, there are a few things that may be to blame.
You may have added the sugar too quickly, the eggs may have been too cold, or your mixture may have been exposed to some fat or oil, either because your mixing bowl wasn’t spotlessly clean, or some egg yolk snuck in when you separated your eggs.
If you’re making French meringue and having trouble whipping up those signature glossy peaks, try folding in another whipped egg to give some extra lift.
Forming a paste from a tablespoon of cornstarch dissolved in ⅓ of a cup of water may also help.
To prevent this from happening you should always allow the eggs to come to room temperature before you use them. When they’re cold, egg whites are more gelatinous, which makes it harder for the air to penetrate them as you mix.
Using fresh eggs is also important, as these are more acidic, and it’s the acidity that helps the egg white’s proteins to stay tightly knit, helping those lofty peaks to form.
