I really like the idea of cooking steak using sous vide. However, I am very wary of heating food up together with plastic, and then eating the food, as I believe that at high temperatures, chemicals from the plastic will leech into the food. *

Is there an alternative to plastic bags for sous vide?

The requirements for the new type of container must be that it is airtight, waterproof, and of course able to withstand heat.

  • Call me paranoid, but I do believe this to be the case - and I do not want to ingest these chemicals
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    60C, the standard temperature for sous-vide, can hardly be called 'high'. It's just about the same temperature as a cup of coffee left out for a couple of minutes. The only alternative would be something like aluminium foil, but I imagine this is more likely to release something nasty than a plastic bag. – ElendilTheTall Mar 29 '11 at 12:13
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    I'm afraid it's a choice between swallowing your fears and swallowing nicely sous-vided food! You probably ingest more 'harmful chemicals' (remember, most things are chemicals!) walking down a street with traffic than you do eating something microwaved in plastic. There are apparently plans for a new polythene being made out of sugarcane, which at least sounds more natural (it's still hydrogen and carbon bonded in a particular way), perhaps you could wait for that? – ElendilTheTall Mar 29 '11 at 13:33
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    I hate to be a nitpick, but sous vide, by definition, requires vacuum sealing. If the alternative does not provide a vacuum, then you can't call it sous vide. </rant> ;-) – ESultanik Jul 11 '11 at 19:15
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    Here's a related question from another SE site on the dangers of heating plastics: skeptics.stackexchange.com/questions/2202/… – ESultanik Jul 11 '11 at 19:15
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    To be fair... Irrational? That's taking it a bit far considering that there are very real dangers associated with some plastics. – Preston May 27 '14 at 7:03

13 Answers 13


First of all, I agree with the others that there is no harm done by plastic bags for sous vide. I have read a statement by the manufacturer that brand-name Ziploc bags don't release anything below 76°C. If you think how much a lawsuit could cost them if the information turned out to be wrong, I trust that they are telling the truth. For other brands, you may have to do some research about safe temperatures.

If you are still unconvinced, your choice of material is very limited. You say it must be airtight and waterproof; I'll add that it must be pliable, so it can cover an irregular steak shape perfectly, without leaving air pockets, and it must somehow be able to create a seal. Also, it must not release any harmful chemicals by itself.

About the only thing that fulfills all criteria would be a wax with a high melting point, like carnauba wax. You could paint the steak with the melted wax, or, probably better, you could soak a piece of gauze in the melted wax and wrap the steak in it, pressing out any air bubbles. Then let it cool and set before cooking. The downside: not only is the food grade wax difficult to source for private people, it also can end up costing quite a bit.

Another option would be silicone, like the one used for baking pans. Unlike plastic, food grade silicone does not contain any chemicals which could leak - the medical sector uses the same stuff for prostethics and implants; it is safe to have it inside your body, so it is definitely safe to cook your food in it. The problem is that you'll need a sealable bag made of silicone, and I don't know if anybody manufactures such bags.

You might consider very tightly wrapping the meat in a caul (not necessarily an amniotic caul, a peritoneum should do nicely) and binding it, but I don't know where you can get cauls. Maybe you can ask a butcher. Also, it probably won't be 100% watertight (but still enough to keep the tasty juices in the steak where they belong, instead of having them flow out into the water).

If you are willing to relax your rules a bit, you can solve the problem much easier. I think you will agree that whatever hypothetical substance might leak from a plastic bag, it cannot travel far through a solid medium. So a steak wrapped in something protective and then sealed in a plastic bag should be safe - you just discard both the plastic bag and the presumably contaminated protective substance. Yes, it is possible that meat juices that have come in contact with the plastic bag end up on the steak, but the possible contamination should be hundreds of times less than if direct contact is allowed between the plastic and the meat.

If you can live with this option, the usual insulators used in the kitchen should do. They are plant leaves - I'd use grape leaves, but you can use practically anything that is big enough - and batters, like tempura batter (breading leaves an irregularly shaped surface, so I won't consider it here, you'll end up with lots of miniature air pockets). If using a batter, you will want to first set it in a pan with very hot oil, just hold it there long enough to set the batter, but not enough to warm the meat on the inside above the sous vide temperature. Both of these options wont't function on their own, as they won't create a sealed waterproof barrier. But combined with a plastic bag and later discarded, they should be a good solution. The leaves will also add a nice taste of their own.

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  • Batter would be awkward- it would definitely become a soggy mess in the bag and wouldn't stop any chemical diffusion. A silicon bag would be awesome. – Sobachatina Mar 29 '11 at 13:58
  • @Sobachatina As the outer bag would be sealed watertight, it will only become somewhat soggy from the meat juices. Still, it shouldn't get actually liquid, so there shouldn't be any currents inside the batter to bring contaminant molecules from the outer side to the inner side. We are speaking diffusion of big molecules (Bisphenol A is C15H16O2) through a solid, which is extremely slow, and happens with only a miniscule fraction of the molecules present on the batter, and the plastic-batter and batter-meat interfaces also don't let through much molecules. It's not perfect, but should work. – rumtscho Mar 29 '11 at 14:14
  • The steak and chicken that I have cooked sous-vide released enough juice or fat to easily turn any fried coating into soup. Perhaps lobster or fish would be ok though. – Sobachatina Mar 29 '11 at 14:15
  • "turn to soup" is another matter, thanks for the correction. And I agree that the silicone bag is the best solution. But if Lurch don't have them, I doubt that they exist at all. Maybe they will start making them once sous vide catches on. – rumtscho Mar 29 '11 at 14:30
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    Update: as of 2019 there are many silicon bags available in the market, I even saw one with a vacuum pump! – Luciano Mar 13 '19 at 10:47

The problem is that air must be removed so that the food is not insulated from the water.

Mason jars work fine but you have to fill liquid around your food. Marinades, broth, etc can be used. Some recipes will have to be modified. Some probably just won't work with the extra liquid or the target food won't fit in a jar.

And then there's the issue of undetectable chemicals leaching out of the glass. Sure we've never discovered any but that's hardly conclusive. :)

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  • +1 @Soba : Thanks for the suggestion of jars - If I cannot find silicone bags, I'll do this – bguiz Mar 30 '11 at 3:06
  • Wouldn't the mason jar solution be more like poaching than sous-vide? – Aaronut May 24 '11 at 0:28
  • @Aaronut- sous-vide is a lot like poaching. I personally like using ziploc bags myself so that extra liquid isn't required. Still with mason jars less liquid would be required than actual poaching and you get all the benefits of the temperature control. – Sobachatina May 24 '11 at 1:22

A company called Lekue makes 1 liter resealable bags out of silicon. You can find them on Amazon for $20 at the moment.

I have not used them myself. I've heard some complaints of leaking, which would obviously be a showstopper. But if you get one that does not leak, and think that the silicon manufacturing process leaves no unsafe chemicals, then they could be your best option.

The side benefit is they are reusable instead of piling more waste in the landfill.

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Food grade disposable gloves work fine (latex or others). Wash them first as many have starch based release agent in them which may effect food presentation

You can either use a vacuum pump, or just immerse filled glove in water just below the opening so as to push out the air. Then tie off with kitchen string. Sort of the reverse of a party balloon

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    How would this differ from using food grade plastic bags? I mean, it's not a bag, but it seems like whatever chemical concerns the OP has would apply to gloves too. – SourDoh Feb 6 '14 at 19:39
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    Latex is not a plastic – TFD Feb 7 '14 at 4:35
  • Your answer doesn't refer only to latex gloves. – SourDoh Feb 7 '14 at 16:06
  • "Rubber" gloves are stinky to me, but if you don't mind use them? – TFD Feb 7 '14 at 23:54
  • fun idea. might just turn the glove inside out so the starch powder stays away from the food. – Luciano Mar 13 '19 at 11:02

You could also consider a combi-oven or water vapor oven. They're sometimes called "sous vide without bags". The very moist air is a great heat conductor and foods come out just beautifully. But the ovens are not cheap.

Keep in mind that not all plastic is created equal, and while not all of it is heat-stable at the temperatures we're discussing some of it is very, very stable.

Polyethylene (NOT polypropylene!) is a great sous vide and freezer-storage plastic. It's also used in cryovac, which means that your meat was likely stored and wet-aged in it prior to final butchering at point of sale. It's the plastic found in Rival Seal-a-Meal, FoodSaver and Ziploc. Also no PVC or phthalates. I've been told some off-brands use different plastics (NOT verified!), and that's one reason why I don't use other brands.

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  • What you suggest first is a steam oven; the problem is that there's no temperature control, it's always hot steam. – Luciano Mar 13 '19 at 11:00

Sheep stomach would likely work, as for Haggis as might intestine from a large enough animal. Barring anything quite that 'organic', Cellulose or Collagen based sausage casings should work. You can buy them in a variety of sizes; 3.675" (93 mm) is easy to find.

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If found a three-pack of those silicone dough-kneading bags on Amazon that are rated from -40°F to 450°F. The bags can go in the fridge or freezer for marinating or food storage. They came today, and they are plenty large for doing large batches of dried beans (195°F) and rice (200°F) sous vide. (I was using gallon-sized ziplock bags until I read that the seams break down above (I think it was) about 158°F.)

These dough bags look large enough to each hold one of those pork sirloin tip roasts from Costco, which around here come in three-packs. How convenient.... I'd use the water displacement method, not vac-sealing, so for anything that doesn't have a lot of liquid, I'd try to find some kind of bag clip capable of working with them. But most of what I cook sous vide is done in a liquid and usually for not more than 12 hours, so I just displace the water and clip the bag over the side of my square container.

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  • Hello, and welcome to Stack Exchange. This is interesting, but doesn't answer the original question. – Daniel Griscom Aug 25 '16 at 11:13
  • @DanielGriscom Silicone is often regarded as distinct from plastic, and indeed other answers mentioned it as a possible option and the OP seemed to like the idea, so this seems like an answer to me - a specific product suggestion, and some notes about how it'll work. – Cascabel Aug 25 '16 at 16:06
  • @Jefromi "Plastic" covers a broad variety of materials, often including silicone. And, the original poster's concern about chemicals leeching from "plastic" bags applies just as much to silicone as to petrochemical-based plastics. – Daniel Griscom Aug 25 '16 at 17:32
  • @DanielGriscom Well, point that out if you want, that's fine, but it doesn't seem to be the view of the OP or other answers here, so it definitely doesn't make it not an answer. – Cascabel Aug 25 '16 at 17:59

A thin walled pyrex bowl worked somewhat for me: http://www.cookskit.co.uk/shop/vclose1.asp?prd=1841&cat=371000327

Throw the goods into the bowl and apply the bowl's cover. Let it float on top of the bath.

It will only work if your sous vide cooker has a lid. If you don't have a lid over the bath, the bowl will not heat through. I tried without cooker lid and failed.

It also takes way more room in the cooker than bags do. Only useful if you heat just one portion.

For vegetables at 90°C it worked perfectly.

For meat at 54°C it worked very much slower than a bag. Still, if you can leave it in long enough, it will work.

I found it unsuitable for steak and fish, because of the increased cooking time and uneven heating, even with turning the goods. But I will always use it for hot stuff like veggies.

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As the public has been increasingly conscious of BPA and its alleged effects, I've seen more and more BPA-free plastic products hit the market. FoodSaver now produces BPA-free bags, presumably to address your exact concern.

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  • FoodSaver bags have, AFAIK, always been polypropylene, which doesn't have BPA in it. Other bag materials in common use are polyethylene, which is also BPA-free. The major plastic with BPA is polycarbonate, and I don't know if anyone has ever made a bag from it... it's more expensive, I believe. (BPA is in a lot of non-plastics as well) – derobert Jul 11 '11 at 19:17
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    I'm sure they have always been BPA-free; recently they've specifically advertised as being such. – Ray Jul 11 '11 at 19:54

There are zip-loc bags with aluminum foil insides. This might be the most practical option. we try to avoid aluminum usually, but perhaps is more preferred over plastic. Thanks

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Just saw these reusable silibagz on indiegogo, they claim to seal airtight and the cylindrical design makes it easy to stand on its own for mixing ingredients. But they're $30 plus $7 shipping to the U.S. https://www.indiegogo.com/projects/sawatdee-silibagz

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I've been thinking of cooking fish and beef fillets using Pyrex dishes filled with vegetable oil as a good conductor of heat around the food. Chefs have been oil poaching fish for ages. Air is not such a good heat conductor, thus air is removed out of the foodsaver bags. Sure, some of the juices of the fish or beef will end up in the oil bath, but I'm willing to sacrifice a little of that for my health. Plastics leach many chemicals with and without heat (we never heat IV bags and tubes, yet it's proven they leach harmful chemicals) so just knowing BPA is taken out (only after the consumer outrage) doesn't make me feel any better.

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    Are there any specific "harmful chemicals" that you are aware of leaching, or are concerned about? – Ray Jul 11 '11 at 19:56
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    pyrex isn't as good of a conductor as you may think, it's more well known for it's heat resistant properties but will take a lot longer to transfer heat in this situation and especially in a container full of oil. – Brendan Jan 29 '13 at 20:54

I'll remind you of the old ways: batter, clay and salt dough used in a similar way to duck skin.

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    Are you suggesting to wrap meat in salt dough for sous vide? It will get washed away, and you'll be lucky if the thickened water doesn't damage a pump. Similarly clay: you can't bake it first, so it will just muddy the water. – rumtscho Jul 7 '14 at 23:26

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