GETTING MY PVC VALVES TO WORK

So espresso luggage have these ingenious just one-way "degassing" valves on them made of membranes that open up if the strain builds up inside. This is why you may "wake up and scent the espresso" with no actually opening the bag. When air attempts to thrust in from outdoors, it flattens the membrane and seals the bag limited. To date so great, but