How to Remove Air from a Plastic Bag?

Removing air from a plastic bag, often referred to as vacuum sealing without a machine, is a simple yet highly effective technique to preserve food, organize items, and protect them from moisture and oxidation. One of the most efficient methods leverages the principle of water displacement.

The Water Displacement Method (DIY Vacuum Sealing)

This technique is remarkably effective at expelling nearly all air from a resealable plastic bag, creating a seal comparable to that of a vacuum sealer, all without the need for specialized equipment. It is particularly useful for food storage, especially for items intended for freezing or prolonged freshness.

Materials Required:

• A high-quality resealable plastic bag (e.g., a freezer-grade zipper-lock bag)
• A large bowl, pot, or basin filled with water
• The food or item(s) you wish to seal

Step-by-Step Guide:

1. Load the Bag: Place the food or items you intend to seal into your resealable plastic bag. Ensure not to overfill the bag, leaving enough space for proper sealing.
2. Partially Seal the Zipper: Close the zipper seal of the bag almost entirely, leaving a small opening—approximately half an inch to one inch—at one corner. This small gap is essential for air to escape.
3. Gradually Submerge the Bag: Slowly lower the bag into the water-filled bowl or pot. As the bag descends, the external pressure exerted by the water will naturally push the air out through the small, unsealed corner.
4. Utilize Water Pressure to Expel Air: Continue to immerse the bag into the water. As demonstrated in a Serious Eats video on vacuum sealing without a machine, it's advised: "You want to keep going down until just that little corner of the bag that you left open is about to be submerged. And just before it goes underwater. You seal. It." The surrounding water pressure will efficiently force the air out from around your bag's contents.
5. Complete the Seal: Just as the final open corner is on the verge of being submerged, swiftly and firmly close the remaining portion of the zipper. This action traps the near-vacuum created by the water displacement.
6. Remove and Store: Once the bag is fully sealed, lift it out of the water. You should now have a tightly sealed bag with minimal residual air, perfectly prepared for storage.

Why Is Air Removal Important?

Removing air from plastic bags offers several significant benefits, especially for food preservation and storage:

• Extended Food Preservation: By reducing oxygen exposure, you minimize the processes that lead to spoilage, freezer burn, and nutrient degradation in food, thereby significantly extending its shelf life.
• Optimized Storage Space: Air removal compresses the bag's contents, making them flatter and more compact, which saves valuable space in freezers, refrigerators, and pantries.
• Enhanced Protection: It creates a barrier against moisture, foreign odors, and contaminants, protecting the items inside the bag.
• Effective Marination: For food items, removing air helps marinades achieve closer contact with the food, leading to more even and effective flavoring.

Other Simple Methods for Air Removal

While the water displacement technique excels at creating a near-vacuum, other straightforward methods can be used for general air removal, especially when a perfect seal isn't critical:

• Manual Pressing: Lay the bag flat on a clean surface. Starting from the sealed end, firmly press down with your hands, systematically pushing the air towards the open end before quickly sealing it shut.
• Straw Method: Insert a drinking straw into the bag, then seal the bag around the straw. Gently suck the air out through the straw. Once most of the air is removed, swiftly pull out the straw and immediately complete the seal.

By applying these practical methods, you can significantly improve the storage and preservation of a wide array of items, from perishables to household goods.