Blanching means cooking something (usually vegetables) briefly in boiling water. After blanching, the vegetables are plunged into a bowl of cold or ice water to stop the cooking. Blanching sets the color and texture of many foods and kills enzymes that make food decay.
Exact blanching times vary with what vegetable you use and what you’re using it for.
Blanch vegetables in a large pot so they are not crowded. Fill the pot with water and bring it to a full boil. Some sources recommend adding salt or sugar — about 1 tablespoon — to the water. This will season the vegetables slightly and set the color, they say.
Recipes may require blanching vegetables before canning to help set the color. You can blanch vegetables before freezing them, though not all vegetables require doing so.
To remove skins from tomatoes or peaches, score an X on the bottom. Blanch for 20 to 30 seconds (times can vary). Remove using a slotted spoon and plunge in ice water. Once cool enough to handle, the skins should easily slip off. Or you can use a paring knife to remove the peel.
Blanching is also a good way to get those pesky skins off small pearl onions. Cut off the tip and blanch the pearl onions for about 40 seconds. Use a slotted spoon or mesh strainer to remove the onions and place them in ice water. Squeeze the onion at the root end so the onion pops out of the skin.
— Susan M. Selasky
Detroit Free Press