Pressure Cookers: 2011 and beyond in Kitchen Consumer Posted January 9, 2013 dont understand the above: 1 bar is about 1 atmosphere of pressure. at sea level. obtainable with normal water at any temp.0.8 bar is sub-atmospheric pressure, obtainable in a partial vacuum.???Isn't the convention to talk about the additional pressure beyond normal. 1 bar + whatever additional pressure is provided by the pressure cooker?