Blanching or steaming: which best preserves the nutrients in vegetables
Boiled vegetables lost 45% of their vitamin C, while steamed vegetables lost only 15%.
Blanching and steaming are gentle cooking methods using very hot water, which retain more nutrients than other, more intense techniques. In a direct comparison, boiled vegetables lost 45% of their vitamin C and 40% of their folate (B9), while steamed vegetables lost only 15% of each.
Blanching is used to preserve the color, flavor, and texture of delicate foods, such as tender asparagus or fresh peas, and of products that will be preserved or frozen. It also cleans products before freezing and can stop the growth of microorganisms.
To steam vegetables, simply place a metal basket or bamboo steamer over a pot with a little boiling water in the bottom. Add the vegetables, cover the pot, and in a few minutes, they will be tender and retain their flavor. It's best to leave between two and five centimeters of water between the water level and the bottom of the basket, and you can add herbs such as fresh garlic, ginger, or rosemary.
Blanching involves boiling vegetables for a very short time. Wait until the water is fully boiling before adding them, cover the pot, and start timing from when it returns to a boil, which is surprisingly short. Then remove the vegetables and plunge them into an ice bath to stop the cooking process.
According to Bon Appétit, an ice bath is unnecessary for everyday cooking, and blanching should be reserved for preserving delicate flavors or for peeling foods like almonds, peaches, or tomatoes. Under normal circumstances, running cold water from the sink and draining the food is sufficient to stop the cooking process.
