In blanching the food is placed only very briefly – seconds to a few minutes depending on size and type – into plenty of vigorously boiling, usually salted water and then immediately shocked in ice water. The sudden cooling stops the cooking process at exactly the right moment, so the vegetable stays crunchy and keeps its bright colour. Green vegetables such as beans, broccoli or peas thus retain their fresh green instead of turning dull and grey.
The process: salt the water heavily and bring it to a rolling boil, and prepare a bowl of ice water alongside. Add the vegetables to the boiling water in portions (beans approx. 2–3 min., broccoli florets 1–2 min., spinach a few seconds), lift them out quickly with a slotted spoon and immediately plunge them into the ice water. Once cold, drain. For tomatoes or peaches 15–30 seconds in the boiling water is enough to peel the skin easily.
Blanching is indispensable for anyone who wants to prepare vegetables and only finish cooking them briefly later – for example mise en place in restaurants, for buffets or for freezing. Vegetables blanched before freezing keep colour, structure and nutrients much better, because otherwise the enzymes, left unstopped, would keep working in the freezer. The method also serves to remove bitterness (e.g. in certain cabbages) and to peel almonds, tomatoes or peppers.
What to watch for: use plenty of water and enough salt, the water must boil hard (otherwise it cooks too slowly and turns mushy), and keep the ice water really ice-cold. Do not blanch too much at once, or the water temperature drops too far. Blanching costs nothing but water, salt and ice and needs no special equipment.