25 minutes.

Generally the old corn is cooked when cooked in boiling water for 25 minutes, or you can decide exactly how long to cook the old corn according to your taste.

If the corn is relatively fresh, then generally speaking, when the water boils, cook for about 10 to 15 minutes is enough time, but if it is old corn or glutinous corn, it is to be on top of this to cook for 5 to 10 minutes more, so that the corn's flavor can be cooked out, and at the same time to cook the corn.

Corn has a very rich nutritional value, which contains anti-free radicals is the longer the cooking time, the stronger the activity, so if you are not in a hurry to eat corn, we can cook the old corn a little longer.

Shopping for corn

1, look at the leaves: the leaves are tender and green, no yellow leaves, no dry leaves, upright is relatively fresh; if it is wilted, it is said to be plucked from the time is relatively long.

2, look at the fracture: if the fracture has a rust-like, certainly not fresh, if black, it is more indicative of this corn is a problem.

3, look at the corn husk. Naked in the outside of the corn husk, is dry; slightly pull open a bit of bracts, see the inside of the corn husk showing inherent color (some green, some white), no wilting, is relatively fresh.

4, look at the corn kernels: corn grains are not collapsed, full of light, gently pinched with a fingernail, able to splash water. If it is old, it will be shriveled and collapsed, the middle of the empty.

5, look at the soft and hard: old corn is very hard, we all like to pick a little tender, so to pull open some leaves to see if the corn kernels are soft and tender. With a fingernail gently pinch, bubbling pulp is relatively fresh.