On Food and Cooking

waxy types (true new potatoes and common
U.S. red-and white-skinned varieties),
neighboring cells cohere even when cooked,
which gives them a solid, dense, moist
texture, and holds them together in intact
pieces for gratins, potato cakes, and salads.
Both types can be made firmer and more
coherent, less prone to the “sloughing” of
outer layers when boiled, by treating them to
the low-temperature precooking that
strengthens cell walls (p. 283).
Cooked potatoes sometimes develop a
large internal region of bluish-gray
discoloration. This “after-cooking darkening”
is caused by the combination of iron ions, a
phenolic substance (chlorogenic acid), and
oxygen, which react to form a pigmented
complex. This problem can be minimized in
boiled potatoes by making the pH of the water
distinctly acidic with cream of tartar or lemon
juice after the potatoes are half-cooked.
The flavor of boiled potatoes is dominated