Waterproof stewing is actually canning the ingredients and separating them from the water in the pot. But after the water is boiled, the heat in the pot is the same as that outside the pot. In fact, it is equivalent to heating stew. The water in the pot gradually loses some moisture with the steam, but there is no need to worry about the loss of water and nutrients in the pot. This has the advantage of no loss of nutrition and original flavor. Don't worry about the undercooked ingredients. In fact, it is a different way of cooking.