A vacuum sealing method and system for evacuating air from and sealing a flexible plastic bag of the type having a mating male rib and a female sealing channel closure along the length of the bag opening. A flowable liquid is applied to the female channel. The rib and channel are engaged along their length to leave a short portion of the closure unclosed, a hollow tubular evacuation tube connected with a vacuum pump is inserted into the bag through the unclosed portion, pinching pressure is manually applied to sandwich the evacuation tube between the unclosed portion to prevent air from escaping, the vacuum pump is operated to withdraw a substantial amount of air from the bag, and thereafter the evacuation tube is quickly pulled from the bag so that the pinching pressure is transferred to the closure thereby closing the unclosed portion and sealing the evacuated bag with the liquid filling voids between the mating elements and providing a supplemental seal to increase resistance to air entering the sealed bag.