How Vacuum-Sealable Lids Work

The one-way silicone valve

Each FreshSeal lid has a small silicone valve built into the top. The valve is one-way: it lets air out of the container and does not let air back in. When the container is sealed, the valve stays closed and the inside stays at lower pressure, so the lid is held tightly in place.

The hand pump

FreshSeal sets include a small hand pump that fits over the valve. A few pumps by hand draw air out of the container through the valve. There are no batteries, no cords, and no countertop machine — the pump works anywhere and stores in a drawer. The same pump also works with FreshSeal vacuum-sealable bags, which come with every set.

Why removing air matters

Oxygen is one of the main reasons food loses freshness: it drives oxidation and helps bacteria and mold grow. An ordinary airtight lid traps air inside with your food. A vacuum-sealable lid lets you remove most of that air instead. With less oxygen around your food, freshness, flavor, and texture last longer — up to 5 times longer than conventional storage — and less food goes to waste.

How to seal a container

1. Place the lid on the container, align the edges, and snap the latches closed.
2. Place the hand pump flat over the silicone valve on the lid.
3. Pump until you feel firm resistance — the air is out and the seal is set.
4. To open, gently lift the edge of the silicone valve to let air back in, then unlatch the lid.

Everyday care

FreshSeal glass containers are dishwasher, microwave, and freezer safe. Keep the valve area clean and free of food residue so the seal stays reliable, and see your set's product manual for full care instructions.