create a paste that dries to a protective crust,
though the eggs can also be immersed in a
water solution of the curing ingredients (this
gives a faster cure but also a coarser alkaline
flavor). A mild, soft-yolked version of pidan
is sometimes made by adding some lead oxide
to the cure. The lead reacts with sulfur from
the egg white to form a fine black powder of
lead sulfide, which blocks the shell pores and
slows the further movement of salt and
alkaline ingredients into the egg. (Lead is a
potent nerve toxin, so such eggs should be
avoided; look for packages clearly labeled “no
lead oxide.” A similar effect can be obtained
by replacing lead with zinc.)
Creating Clarity, Color, and Flavor The real
transforming agent in pidan is the alkaline
material, which gradually raises the already
alkaline egg from a pH of around 9 to 12 or
more. This chemical stress causes what might
be thought of as an inorganic version of