What is the difference between a vacuum sealer and a chamber sealer?

A vacuum sealer pulls air out of a bag through its open mouth, using a nozzle or an embossed channel in the bag film, then heat seals the edge. A chamber sealer puts the entire bag inside a closed chamber, drops the pressure in that chamber, and lets the air inside the bag escape through the film, which is why liquids do not get sucked toward the seal.

The practical result is that external vacuum sealers handle dry and moist food with some care, while chamber machines are built for soups, marinades and wet food. The two guides this page draws on, Best Vacuum Sealers for Dry and Moist Food and Best Chamber Vacuum Sealers for Liquids and Sous Vide, list the figures each maker publishes.

How an external vacuum sealer works

An external sealer clamps the open end of a bag onto a vacuum channel. The pump draws air out of the bag through that opening, then a heating strip fuses the bag shut. Because the air leaves through the mouth, any liquid near the opening can travel with it. Makers address this with moisture settings and pulse control. The Gasbye VS5166 lists 95kPa of suction and a Pulse Mode for moist food, and the Beelicious Pro VSP801 lists 98kPa dual-pump suction with an Extra Moist Mode.

These machines are countertop units that hold a roll of bag material and a cutter. The Gasbye measures 15.7 by 7.8 by 4.7 inches and weighs 6.5 pounds. The FoodSaver Compact measures 17.91 by 5.59 by 10.24 inches and weighs 4.5 pounds, and the maker states it stores vertically. The Nesco VS-12 lists a 130 watt double vacuum pump and measures 17 by 15 by 9 inches at 6 pounds.

Smaller formats exist too. The Chef Preserve handheld is listed at 3.94 by 3.94 by 3.94 inches and 2.22 pounds, and the maker states it seals a bag in 5 seconds. The maker does not publish a suction figure for it. That is the pattern with external sealers: the bag is outside the machine, and the machine only controls the air at the bag mouth.

How a chamber sealer works

A chamber sealer places the whole bag inside a lid-covered box. The pump evacuates the box, so the pressure outside the bag falls along with the pressure inside it. Air leaves the bag through the film, the bar seals the bag while the vacuum is still held, and only then does air return to the chamber. Nothing has to flow past the food, so a bag of soup seals without the soup climbing toward the seam.

That construction makes these machines heavier and bulkier. The Wevac CV12 Pro measures 17.9 by 14.5 by 9.6 inches and weighs 29.43 pounds, with an 8.5 quart chamber listed as 12.4 by 12.8 by 3.8 inches. The VacMaster VP230 measures 15.5 by 19 by 15.75 inches and weighs 89 pounds, with a 12.5 by 15 by 5 inch chamber and a 12.25 inch seal bar. The Beelicious Pro CVS101 lists a 6 liter upper chamber and a 230 watt dual-core pump system.

Chamber machines also seal bags that external units cannot use, because the bag does not need a textured channel for air to travel along. The Mesliese unit lists a 6 liter chamber and an 11.3 inch removable dual sealing bar, and the Avid Armor USV20 lists a 4 liter stainless steel chamber with an 11.5 inch heating bar.

Liquids, marinades and wet food

The clearest difference shows up with liquid. An external sealer has to stop the vacuum before liquid reaches the seal, which is why moist modes and pulse buttons exist. A chamber sealer has no such race. The VacMaster VP230 maker states the machine packages liquids and liquid-rich foods such as soups, sauces and marinades, and lists a double seal system. The Wevac CV12 Pro maker describes a detachable tray and washable seal bar so spills can be rinsed in a sink.

Chamber machines are also sold for marinating, since a vacuum cycle pulls marinade into the food. The Beelicious Pro CVS101 maker states its Vacuum Marinate mode drives flavor up to 5 times faster than traditional marinating. The Mesliese maker states its unit accelerates marinating by up to 20 percent compared to traditional methods. Both are maker claims about the process, not figures this site has checked.

External sealers can still handle wet food with the right setting. The Nesco VS-12 lists dry, moist and double seal modes with a gentle vacuum option, and the FoodSaver Compact lists unique dry and moist settings. What they cannot do is seal a loose bag of stock without the stock moving toward the opening.

Size, bags and where the machine sits

External sealers take bags from a roll and cut them to length, and several include the roll storage and cutter in the body. The Gasbye lists built in roll storage and a cutter, and the Nesco VS-12 lists roll storage and a sliding bag cutter. Bag width is limited by the seal bar and the machine’s footprint, not by a box. The Gasbye starter kit lists 8 by 12 inch pre-cut bags and two 11 inch by 10 foot rolls.

A chamber sealer is limited by the chamber. The Wevac chamber is listed at 12.4 by 12.8 by 3.8 inches, so a bag has to fit inside that space along with the food. The VacMaster VP230 maker lists a maximum bag size of 12 by 15 inches and states the 12.25 inch seal bar accommodates up to that size. The Avid Armor USV20 maker states the unit works with smooth pouches up to 11 by 10 inches.

Weight decides where the machine lives. The Avid Armor USV20 is listed at 17.3 pounds, the Beelicious Pro CVS101 at 25.7 pounds, and the Mesliese at 21.38 pounds. The VacMaster VP230 at 89 pounds is a machine that stays in one place. External sealers in these guides run from 2.22 pounds to 6.5 pounds, so they can be lifted into a cupboard between uses.

Which one fits your kitchen

If most of what you seal is dry or only damp, an external sealer covers it with a smaller footprint. The Gasbye at 6.5 pounds and the FoodSaver Compact at 4.5 pounds both store upright or on a shelf, and both list moist settings for the occasional wet item. The Nesco VS-12 adds a 130 watt double pump and a viewing window for checking bag placement.

If you seal stock, soups, marinades or bags of marinated meat, the chamber design removes the problem rather than managing it. The trade is weight and counter space: the lightest chamber unit in these guides is the Avid Armor USV20 at 17.3 pounds, and the heaviest is the VacMaster VP230 at 89 pounds. Chamber machines also accept smooth bags, which the Wevac and Mesliese makers both list alongside textured rolls.

One more distinction is external vacuuming. Several chamber units include a hose and port for jars and canisters, which the Wevac CV12 Pro lists with two Mason jar adapters and the Mesliese lists with two universal lids. External sealers can do the same through a hose port, which the Gasbye lists as part of its kit. Neither design is strictly one or the other on accessories.