Kelp contains fucoidan and alginate, which are insoluble in water but have strong water-absorbing properties. Once absorbed, a viscous gel will appear on the surface of the kelp, preventing the water from further immersion, so it is difficult to soak through the kelp. At the same time, most of the iodine contained in the kelp in the surface, too long soaking will make iodine loss.　　Usually the common practice is to dry kelp first soaked in water and then boiled, in fact, this practice is wrong. This is the wrong way to deal with the kelp no matter how to stew, stew how long to eat still feel not rotten. The correct way to cook kelp: 1, rice water method: in the soaking kelp with rice water, kelp is easy to soak, cleaning, cooking is also easy to soften. 2, the law of moderation: the process of cooking kelp can be used chopsticks to pick up a piece of the hand to pinch, if soft, immediately put the rest of the kelp out, because the kelp cooking time is too long will become hard. 3, alkali trick: kelp in the cooking time with a little (not too much) edible alkali or baking soda, and then the kelp is not too much. 4, add vinegar trick: cook kelp when adding the right amount of white vinegar, not only can remove the peculiar fishy smell of kelp, but also promote the kelp is easier to cook soft color is also good to see. Like a softer texture, you can extend the cooking time. If you put a few spinach, kelp is easy to rot. 5, dry steaming tips: open the dry kelp into a ball in a cage drawer in the water dry steaming for about half an hour, and then soaked in water overnight. With this method of treatment after the kelp and crisp and tender, with it to stew, fried, cold, are soft and delicious. 6, boiling water scald method: if you need to soup with kelp knots, you can put into boiling water before cooking to scald to remove the fishy taste of soup will be more delicious flavor. In the consumption of kelp should be cleaned, according to the actual situation of the water soak and constantly change the water, generally soak for more than 6 hours. If the kelp after soaking in water like boiling like no toughness, that it has deteriorated do not eat.