When using egg whites in a recipe that requires you to whip them it is best to work with room temperature egg whites. I personally find it easier to separate egg whites from egg yolks when the egg is still cold. Crack the egg and pour the egg white into one small bowl and the egg yolk into another small bowl. Then pour the egg white into the large bowl. Keep adding the egg white to a small bowl. If you happen to get a little egg yolk mixed into the egg white you need to discard it. Instead of discarding a whole bowl of egg whites you only need to discard one egg white. Then set the egg whites out on the counter to come up to room temperature.