Do You Need a Vacuum Sealer for Sous Vide?

"Sous vide" is French for "under vacuum," which has convinced a great many people that a vacuum sealer is part of the equipment list. It is not. The name describes how restaurants do it at scale, not what the physics requires.

What the technique actually needs is for the food to be in good thermal contact with the water and for air to be out of the way, because air insulates and makes bags float. A sealed zip-top bag with the air pushed out achieves both. This guide explains how, and then makes the honest case for when you should buy a sealer anyway.

The water displacement method

Free, takes fifteen seconds, and works with bags you probably already own.

1. Put the food in a zip-top freezer bag and seal all but one corner of the top.
2. Lower the bag slowly into the water bath, holding the open corner above the surface. Water pressure presses in on the bag from all sides and forces the air up and out through the gap.
3. When the water level reaches just below the opening, seal the last corner. The bag is now effectively vacuum-packed by atmospheric pressure.
4. Clip the bag to the side of the pot with a bulldog clip so it cannot slide under and block the circulator intake.

Use freezer-grade bags from a major brand rather than thin sandwich bags, and do not reuse packaging that was not intended for cooking. That is the whole technique, and it produces results indistinguishable from a sealer for a steak, a chicken breast or a bag of vegetables.

Fixing bags that float

The one problem worth knowing how to solve, because a floating bag means part of the food is not in circulating water and your timing no longer applies.

Floating has two causes: trapped air, which the displacement method removes, and air released by the food itself during a long cook — vegetables in particular give off gas as they heat.

The fixes are free: rest a heavy plate or a small ceramic dish on top of the bag, drop a couple of butter knives or a spoon into the bag alongside the food as ballast, or clip the bag to the side of the pot so it cannot rise. A proper sous vide rack is worth buying only if you routinely run four or more bags at once and they keep touching, which does cause uneven results.

When a sealer genuinely earns its money

Four cases, and if none applies to you then a sealer is a purchase you can comfortably defer indefinitely.

1. Long cooks. Over roughly twelve hours — short rib, brisket, pork shoulder — a zip-top seal can slowly admit water, and a bag that fills is a ruined cook. A double-sealed vacuum bag is far more reliable for a 24-to-72-hour hold. This is the strongest argument.

2. Batch prep and freezing. If you portion and freeze proteins to cook later, a vacuum seal genuinely prevents freezer burn in a way a zip-top bag does not, and you can cook straight from frozen. This is the case where a sealer pays for itself outside sous vide entirely.

3. Marinades and liquids.Displacement struggles with anything wet, because liquid rises with the air and you end up sealing marinade into the closure. This is exactly what "wet mode" on a good sealer is for — the Anova Precision Vacuum Sealer Pro switches to low-pressure suction with a double seal specifically to handle it.

4. Bones and sharp edges. Rib bones and fatty cuts puncture thin bags. The thicker material used by vacuum sealers is more puncture-resistant, and double-bagging a zip-top is the free workaround.

If you are buying one

Anova Precision Vacuum Sealer Pro — best for sous vide

Built by the people who make the circulator, and the details show it. A wet mode with low-pressure suction and a reliable double seal handles marinades and brines — the exact failure case of the free method. One-handed operation means clamping, vacuuming and sealing without a second pair of hands. It stores a full bag roll and cutter inside the hinge, so the consumable lives with the machine rather than in a drawer. And an accessory port and hose open it up to canning jar lids and vacuum containers.

Cons: overkill if you only seal dry food occasionally, and at 14.75 inches deepit takes real storage space. Note also that the listing's warranty statements are inconsistent — the title and the feature text disagree — so check before relying on a specific term.

Anova Precision Vacuum Sealer — best value

The slim, minimalist version: wet and dry modes, ten pre-cut BPA-free bags in the box, a 2-year manufacturer warranty, and just 2.31 lb so it stores in a drawer. If you have decided you want a sealer rather than zip-top bags, this is the sensible amount to spend.

Cons: no internal bag storage, and less suction than the Pro on dense loads.

FoodSaver PowerVac Compact — best for freezer storage

FoodSaver is the incumbent in this category and the PowerVac is its compact model, storing vertically at 2.95 lb. If your main use is freezing meat in bulk rather than sous vide specifically, the FoodSaver bag ecosystem is the widest and cheapest to feed — and bags are the real ongoing cost of owning a sealer.

Cons: no published warranty on the listing, a shorter seal bar because of the compact body, and it is aimed at freezer storage more than at sous vide.

Edge sealers vs chamber sealers

Worth knowing so you can ignore most of what you will read. Everything sold for home use — including all three picks above — is an edge sealer: the bag sits with its open end in a channel, air is drawn out of the bag, and a heated bar melts it shut.

Chamber sealers work differently: the whole bag goes inside a sealed chamber, and the machine evacuates the chamber rather than the bag. Because there is no pressure difference across the bag, they handle liquids effortlessly — soups, marinades, brines — which is exactly what edge sealers struggle with.

They are also large, heavy and expensive, and they belong in restaurants rather than home kitchens. If you find yourself frustrated that your sealer sucks marinade into the seal, the answer is not to buy a chamber machine — it is to use wet mode, freeze the liquid into a block first, or simply use a zip-top bag and displacement for wet items. That last option is free and works well.

The cost nobody budgets for

Bags. A vacuum sealer is a razor-and-blades product: the machine is a one-off, the bags are forever. Rolls are cheaper per bag than pre-cut pouches because you cut to size and waste less, which is a real argument for a machine that stores a roll internally.

Zip-top bags, by contrast, can often be washed and reused for the same kind of food, which makes the free method cheaper in consumables as well as in hardware. Factor that in before assuming a sealer saves money.

A note on reusing bags

Sensible for zip-top bags used with dry or lightly-seasoned food — wash in hot soapy water, dry thoroughly inside out, and reuse for the same category of food. It makes the free method cheaper still.

Do not reuse bags that held raw meat, poultry or fish, and do not reuse vacuum-sealed bags that have been cut open, since the cut edge no longer seals reliably. If a bag has been through a very long cook, retire it — repeated heat cycles gradually weaken the seams.

The verdict

Start without one. Buy the circulator, use zip-top bags and the displacement method, and find out whether sous vide earns a place in your cooking at all — the honest version of that question is in is sous vide worth it. If you would rather spend the money on something that improves results immediately, buy a cast-iron pan you can get properly hot for the sear, which is half the result and the half a cheap setup does not compromise.

Then buy a sealer once you find yourself doing long cooks, batch-freezing, or fighting with marinades. At that point the Anova Precision Vacuum Sealer is the sensible pick, the Pro if wet mode and the internal bag roll appeal, and the FoodSaver if freezing is really the job. The entry-level machines are in best budget sous vide, and times and temperatures covers what to do once the bag is in the water.