the outset, in order to obtain a very firm,
dense foam.
A Silver Bullet for the Copper Theory
Why do copper bowls make more stable
egg foams? I’ve wondered about this for
many years. In 1984 I did some
experiments with the help of Stanford
University biologists, and then published a
theory in the British science journal Nature
and in the first edition of this book. The
experiments suggested that one of the
albumen proteins, ovotransferrin, takes up
copper from the bowl surface and is
thereby rendered resistant to unfolding —
which could make the foam as a whole
resistant to overcoagulating. That theory
stood up for ten years, until one day on a
whim I tried whipping egg whites in a
silver-plated bowl. Ovotransferrin doesn’t
bind silver, so the foam should have turned
grainy. It didn’t. It remained light and