Blanching is the process where a fruit or a vegetable is dropped into boiling water for a limited time and then shifted to cold or iced water to stop the cooking process. The halting process is also called shocking since there is a sudden change in temperature from hot to cold.
Blanching is used:
1) To help loosen the skin of vegetables, nuts and fruits for peeling
E.g.: Almonds, Pistachios, Peaches, Tomatoes
2) To partially cook before adding to a dish that involves another cooking technique
E.g.: Grilling, Stir fry, Braising
3) To help maintain the bright green color of vegetables
E.g.: Spinach, Green beans, Green peas
4) To remove the bitter taste of a vegetable and give it a “crisp- tender” food texture
E.g.: Asparagus, Cauliflower, Bell Pepper
5) As a preparation method before deep-freezing vegetables for long-term use
E.g.: green peas
Blanching time is an important factor and varies with the size and nature of the vegetable. For green leafy and shredded vegetables, time taken is 30 sec and the hard ones take a little longer. For vegetables, it varies from 2-5 min. If a mix of different kinds of vegetable is used, blanch each one separately, lighter colored ones first followed by darker ones. Put vegetables in boiling water. The water should start boiling within a minute on a high flame. If water doesn’t boil in a minute, it means excess vegetable has been used for that quantity of water. Ideally, for half kg of cut vegetable 3 litre of water and 1 tbsp of salt should be used.
Water may or may not be salted depending on the vegetable or the dish. If you choose to add salt in water, make sure that you add an extra amount so that it prevents discoloration of vegetables and also stops the nutrients from leaching out. Cooling and blanching time should be the same. Dry them up soon after.
Note: Blanching is different from parboiling