This is normal, the beginning stage and the final exhaust, will bubble out more. In the middle of the work, there will be very little gas excluded, this is a normal phenomenon. Because at the beginning of the electric pressure cooker work inside the temperature is not very high, the air pressure is not very large not enough air pressure to the top of the exhaust valve inside, wait until the temperature inside is high, the air pressure is also large, the exhaust valve is naturally on the top of the, so there is no sound, in the process of almost fully sealed, you think about what you cook when there is no smell of food However, I don't know what brand you purchased

The computer motherboard pressure control electric pressure cooker is also good, is through the computer motherboard to control the temperature inside the pressure control.

There is also a mechanical pressure control of the electric pressure cooker, which is currently the best electric pressure cooker on the market, the principle is that when the atmospheric pressure in the pot more than 1.8, the inner liner inside the automatic downward movement, at the same time the power off, when the atmospheric pressure inside the pot is less than 1.8 liner automatically back to the same time the power, so it is currently the most secure.