Winter weather is cold, and tap water is bone-chilling, making washing vegetables the most miserable task in the kitchen. Therefore, many people, unable to stand the cold, just hastily rinse the vegetables under the tap. In fact, in winter, you might as well be a bit "fussy" when washing vegetables. Washing them with warm water is not only more comfortable but also safer.
Everyone knows that warm water doesn't freeze your hands. But why is it also safer? What we fear most when washing vegetables is not getting them "clean enough," with the biggest concern being the organophosphate pesticide residues. This substance is easily soluble in water, and its dissolution accelerates as the water temperature increases. At the same time, carbamate insecticides in pesticides also break down faster as the temperature rises. Therefore, warm water is more effective than cold water at removing pesticide residues from the surface of fruits and vegetables.
However, some people might worry that the nutrients in fruits and vegetables are already so delicate; wouldn't hot water destroy them all? The key to washing vegetables with warm water is to control the temperature, with around 40°C being ideal. Otherwise, if the water is too hot, you will lose vitamins B1, B2, vitamin C, and some niacin and minerals from the fruits and vegetables during washing. However, controlling the water temperature is quite simple. You can test it with your hand first; water at 40°C feels warm but not hot. So, when you wash vegetables, as long as you feel it's warm and not scalding, the nutrients can be comfortably preserved.
So, what are the special requirements for washing different types of fruits and vegetables? For root vegetables, such as potatoes and sweet potatoes, you can first wash the surface with warm water, and then use a soft brush to carefully scrub away the dirt from the uneven areas. Leafy vegetables have a shorter growth cycle and thus tend to have higher pesticide residues. You can first soak them in warm water for 15 minutes, and then rinse them with warm water or add a small amount of salt for cleaning. Vegetables like cabbage and Napa cabbage should be cut before washing. For flower vegetables, such as broccoli, you can first soak them in warm water for about 20 minutes, then cut and wash them. You can also blanch them in boiling water before cooking. For fruit vegetables, such as green beans and eggplants, they should be soaked whole in warm water before being cut. For fruits like apples and pears, some have a layer of wax and preservatives on their surface, which are easier to wash off with warm water. You can add a little salt to use the small salt granules to grind off the surface wax.