By Harold McGee
Next to the yolk’s riches, the white seems colorless and bland. It accounts for nearly two thirds of the egg’s shelled weight, but nearly 90% of that is water. The rest is protein, with only traces of minerals, fatty material, vitamins (riboflavin gives the raw white a slightly yellow-green cast) and glucose. The quarter-gram of glucose, which is essential for the embryo’s early growth, isn’t enough to sweeten the white, though in such preparations as long-cooked eggs and thousand-year preserved eggs it’s sufficient to turn the white a dramatic brown. The white’s structural interest is limited to the fact that it comes in two consistencies, thick and thin, with the yolk cords being a twisted version of the thick.