Vacuum sealing food and freezing it is the best way to preserve its freshness, and vegetables are no exception. A vacuum sealer works by sucking all of the air out of the bag the vegetables are in and sealing the bag tight to lock in the freshness of the vegetables.
Wash the green beans and cut 1/4 inch off each end of the beans.
Fill the cooking pot two-thirds of the way with water. Place it on the stove and bring the water to a boil.
Fill the mixing bowl with ice and water to create an ice bath.
Place the green beans into the boiling water. Allow them to boil for precisely three minutes.
Remove the green beans from the boiling water with the steel strainer and plunge them into the ice bath. Allow them to cool in the ice bath for three minutes.
Remove the green beans from the ice bath. Place them on a paper towel and use a second paper towel to pat them dry.
Cut the vacuum sealer bag so that the bag is three inches longer than the green beans being sealed.
Insert one end of the bag into the sealer and press the "Seal" button.
Place the dry, blanched green beans into the vacuum sealer bag.
Fold over the end of the bag (keep the bag closed with a clip if you'd like) and place the bag in the freezer. Vacuum sealers are very powerful, and the vacuum process can easily flatten soft foods like blanched green beans, as well as pull out natural moisture and juices. Freezing before vacuuming hardens the beans, preventing them from being crushed in the vacuum-sealing process.
Remove the bag from the freezer and insert the open end into the machine. Most vacuum sealers can be controlled to seal only, vacuum only or to do both functions at once. Depending on your model, press the appropriate buttons to do both functions at once, then wait as the machine takes several seconds to suck all the air out of the bag. A the end of the vacuum process, the machine will then seal the bag.
Place the vacuum-sealed green beans in the freezer. Vacuum-sealed green beans will hold up frozen for roughly 10 to 12 months.
Some newer high-end vacuum sealers have a "soft-seal" setting that minimizes the damage to soft foods when vacuum sealing. For machines with this option, freezing before vacuum sealing may not be necessary.