Blanch and shock vegetables
Drop green vegetables into well-salted boiling water for 1 to 3 minutes, then straight into ice water. The brief heat drives out trapped air so the green looks vivid. The ice bath stops the cooking, so they stay crisp.
Heat and acid dull green color
Heat and acid turn green vegetables from bright green to dull olive. That's why beans simmered 20 minutes in tomato sauce look drab. Cook greens briefly, and add lemon, vinegar or tomato at the very end.
Blanching times and water volume
Green beans and asparagus need 1 to 3 minutes, and broccoli florets 2 to 3. Pull one out and bite it: it should be bright and crisp-tender. Use plenty of water, about 4 L per 450 g, so it keeps boiling when the vegetables go in.
Test yourself
Questions from the interactive lesson, with the answer and the why.
You just blanched green beans for 2 minutes. How do you keep them bright and crisp?
Plunge them into ice water right away. Cold water halts the cooking, which keeps the color and crunch.
True or false: Letting blanched vegetables cool on the counter keeps them as bright as an ice bath does.
False. Slow cooling lets leftover heat keep cooking the vegetables and dulls the color.
What went wrong? You boil green beans for two minutes, then drain them into a colander and leave them. They turn dull and soft.
They skipped the ice bath. The beans kept cooking from their own heat in the colander.
Fill the blank: Green beans need about ___ in boiling water before the ice bath.
Green beans need about 2 minutes in boiling water before the ice bath. That's long enough to turn them bright and crisp-tender.
Green beans with and without an ice bath
Bright green isn't an accident.
Do the 15-minute experiment