There's more to cooking vegetables than tossing them in a pot. Some cook more evenly when heated up gradually, while others should be put directly into boiling water. So when do you use which?
Image from janitors.
This rule is simple to remember:
- Vegetables that grow underground (potatoes, carrots, beets, turnips), should start off in cold water.
- Vegetables that grow above ground (greens, peas, corn) should be placed into already boiling water.
Farmers' Almanac explains why this technique works:
Cooking the corn, peas, etc. simply entails softening their cell walls to make them more palatable and easier to digest. Because most green vegetables are small and/or thin, this doesn't take long. So you add those to boiling water. Root vegetables contain a great deal of starch, which needs to be dissolved before they can be eaten. As root vegetables cook, "It takes a while for the heat to penetrate. Starting root vegetables out in cold water and heating the outside layers gradually allows the cell walls get reinforced and become more resistant to the effects of overcooking."
This works especially well on starchy root veggies, like potatoes, since the gradual temperature change keeps the outer edges from overcooking and turning mealy.
When to Boil Water [Farmers' Almanac via Facebook]