Blanching is a method of cooking in
boiling water, with the implication that the food will be further cooked
after blanching. For example, root vegetables or tubers such as potatoes
or turnips may be blanched in boiling water until barely cooked through
before being sautéed, grilled or roasted. Slow cooking root vegetables
would otherwise overcook on the outside before the intense heat of the
sauté pan or grill penetrate the dense flesh to the interior. Large root
vegetables are blanched starting in cold water so that the heat penetrates
them gradually and they cook more evenly.
Older turnips are sometimes sectioned
and blanched, starting in cold water, to eliminate any bitterness. Meats
and bones are sometimes blanched to eliminate the scum that would
otherwise cloud the poaching liquid or broth. Tomatoes and peaches are
often blanched to loosen their skins and make peeling easier.
Sometimes people add baking soda to
the water used for blanching green vegetables. As baking soda is alkaline,
it neutralizes natural acids contained in the vegetables and turns the
vegetables bright green. Unfortunately, baking soda also causes vegetables
to turn mushy.