Keep heat on high for the total blanching time specified in Table 1. Follow the recommended blanching time for each vegetable. Underblanching may stimulate enzyme activity and could be worse than no blanching. Prolonged blanching causes loss of vitamins, minerals, flavor and color. Steam Blanching Heating in steam is another way to blanch vegetables.
Steam blanching takes somewhat longer than water blanching but helps retain water-soluble vitamins.
Steam-blanching times are given in Table 1 for those vegetables that steam most successfully. To steam vegetables, bring 1 to 2 inches of water to a rolling boil in a kettle with a tight-fitting lid and a rack that holds a steaming basket or cheesecloth bag at least 3 inches above the bottom of the kettle. Place the basket or bag on the rack in the kettle, cover and keep heat on high. Start counting steaming time as soon as the lid is on. After vegetables are heated, cool quickly and thoroughly to stop the cooking.