When you beat egg whites, use room temperature eggs in order to get the most volume. You can use a handheld mixer or a stand mixer, but if you use a stand mixer, watch carefully because it’s easy to overbeat. If you’re using a handheld mixer with attachments, use the whisk attachment.
The first stage of beating egg whites is the foamy stage. When lightly beaten to this stage, the whites will look bubbly and foamy.
The next stage is the soft peak stage. When the egg whites are beaten to the soft peak stage, the whites will mound, but no sharp tips will form.
For egg whites beaten to the stiff peak stage, beat until sharp tips form when the beaters are lifted.
When egg whites are overbeaten, they look curdled and dry. There’s no restoring overbeaten egg white, so you’ll need to start again.