Meringue pies will ''weep'' water because of the interaction between the filling and the whipped meringue. If one or the other is overcooked, water beads will form and weep. Egg whites can also weep if they are over-beaten or are from old eggs. Refrigeration (unfortunately) speeds up the process of weeping—oops! It's so tough to tell where the problem lies that you might want to use a pre-cooked meringue.
Here's how to make meringue topping:
I have tried many tricks and tips, but I now follow Martha Stewart's advice and never have a problem:
''Meringue toppings on pies don't always hold up for long periods of time, particularly in humid weather, so plan to add the meringue shortly before serving. Weeping and shrinking (when the meringue pulls away from the crust) are two common problems, but they are avoidable. Refrigeration makes meringue weep more quickly, so let the pie stand at room temperature in a draft-free spot before serving it. After a few hours, however, it will need to be refrigerated.
''If the meringue is cooked before being added to the pie, it will be more stable and less likely to weep. To do this, combine the sugar and egg whites ... in a heat-proof bowl and set over simmering water. Mix until the egg whites are warm, then remove from heat and add the salt and/or cream of tartar. Beat into stiff peaks.
''Spread the meringue over a pie that is already baked, covering the filling completely and touching the crust all the way around. This will prevent shrinking. If you like golden peaks on your meringue, run the pie under the broiler for one or two minutes. Serve as soon as possible.'' (Source: Dessertsby Martha Stewart, Clarkson Potter, 1999)
A version of this story originally appeared on iVillage.