The Science of Whipping Egg Whites
Whipping Egg Whites
The Science of Whipping Egg Whites
Copper bowls should always be used when beating egg whites. Copper tends to absorb the heat friction caused by the beating, which tends to stop the formation of the air packets needed to form bubbles of air. The copper will also release ions during the beating process that causes the protein in the mixture to become stiffer. If the copper bowl is used, you will not need to use cream of tartar.
Next best is stainless steel; however, a pinch of cream of tartar needs to be added to accomplish the stabilization. Make sure either bowl has a rounded bottom to allow the mixture to fall easily to the bottom and come into equal contact with the mixing slightest hint of fat has a negative effect on the final product. Remove any yolk with a piece of the eggshell.
Never use a plastic bowl for whipping egg whites since plastic has the tendency to hold on to fats. The salt and cream of tartar are added after you beat the eggs and they just barely start to become foamy. The proportion of sugar is important: 2 tablespoons per white for soft meringue and 4 tablespoons per white for hard meringue. Never add the sugar until the foam starts to appear.
When egg white protein is cooked the bonds that hold the proteins together unravels and creates a new protein network. The molecules of water that are in the egg are trapped in this new network and as the protein continues to cook the network squeezes the water out. The longer and the more heat than us used, the more water is released and the more opaque the white becomes. If you over cook the egg it will release all its moisture and will have a rubbery texture. The nutritional value of dried out eggs is the same as fresh eggs.
I could not believe all the trouble some chefs go through to make sure that there was not even the slightest trace of yolk in the vicinity when they are going to whip eggs whites. It seems that even a slight trace of yolk (the fats the problem) will stop egg whites from whipping. They also use a large whisk with many wires to provide as much air as possible to enter the egg whites.
The four stages of whipped egg whites
It is really important to know when to stop beating egg whites. Recipes usually indicate a stage to which the foam should be beaten.
The whites should be lightly whipped to just barely frothy and still maintain a fluid consistency. It should consist of many bubbles on the surface that easily pop. This foam will not hold any peaks as the whisk is lifted from it.
The foam is moist, shiny and bright white and when the whisk is lifted out, the foam forms a weak peak what will fall over and curl gently. The foam will flow if the bowl is titled. When this point is reached, the foam is at the maximum volume.
Over beaten Whites
It happens more frequently when using an electric mixer. The foam will appear dry and granular. When this occurs you can save it by adding another egg white and beat until you have the desired peaks.
Creating a Foam
Many recipes call for beaten egg whites. They are used to provide rising power, lightness and puffiness to foods. Creating foam is an art and there are many pitfalls that you should be aware of, as well as methods of repairing a foam problem. The following are some of the more common problems and their solutions.
The slightest bit of fat can affect the foam developing and retaining its shape. This usually is a problem of a small bit of egg yolk being left in with the whites.
Adding a small amount of an acid, such as lemon juice or cream of tartar will cause the volume to increase.
Egg will develop better foam if they are allowed to remain at room temperature for 1 hour before they are used.
Never over beat, the more you beat, the more the whites will look dry and curdled.
Add a small amount of sugar and the whites will remain stiffer for a longer period.
Beating too much will cause the peaks to be too fragile.
A number of companies are selling egg whites. These products can be used the same as you would ordinarily use eggs. However, if you recipe calls for egg yolk, you cannot use only the whites in more instances. If you are making scrambled eggs or any dish that calls for egg whites alone there should be no problem using these products. Be sure the label states that the product is pasteurized and it is salmonella-free. The pasteurization process does utilize high heat so that the products many not respond as well as the fresh egg whites in certain recipes.