Whipping Time

When whipped too quickly or for too long, proteins denature and aggregate extensively, and the protective film that surrounds each air bubble becomes overstretched and rigid. The whites eventually collapse, forming tightly bonded, inflexible clumps of protein floating in squeezed-out liquid. In other words, too much whipping has a curdling effect on egg protein structure similar to the effect of too much heat. Over-whipped whites should be discarded.