Not necessarily, boiling water is just a little faster, in fact, it is just a 2-3 minutes faster, completely unnecessary, the steps can be referred to as follows: the amount of water in the pot plus pig's trotters is not more than one-half of the pot, 2 minutes after the boil, adjusted to a small fire, such as like a soft and rotten on the 30 minutes, such as to be a little bit of a hard on the 20 to 15 minutes. Note that after turning off the heat, do not be in a hurry to remove the pressure reducing valve, wait until the natural decompression is good.