A hand held electric mixer works quite well for beating egg whites, because it allows you the freedom of moving the spinning beaters all around the interior of the bowl, keeping the egg whites in constant motion. A stationary mixer, which has a beater that not only spins but also rotates within the circumference of the bowl, is an excellent tool and eliminates all of the manual work. Some stationary models have beaters that do not move around the inner circumference of the bowl, but rather, the bowl travels on a rotating stand as the beaters spin within the bowl. Kitchen tools such as blenders and food processors are not suitable for beating egg whites.
When using any electric mixer, begin beating the egg whites at a slow speed. Continue beating for about 1 minute. Cream of tartar can be added to the egg whites for stabilization of the beaten whites. After beating on a slow speed for 1 minute, gradually increase the speed until the egg whites reach their full volume. Don't be tempted to operate the mixer at high speed from the beginning of the process. This will not speed the process of beating the egg whites; in fact, the egg whites will not reach full volume. The entire beating process usually requires no more than 3 minutes when using a high quality electric mixer.
The beaten egg whites should be folded immediately into any other ingredients used in the selected recipe. It is a good idea to have the other ingredients prepared and measured prior to beating the egg whites. The reason for this is because when the egg whites are beaten first and then set aside, the beaten egg whites will break down and lose volume while the other ingredients are being prepared, which will result in a substandard outcome.