When you cook meat (beef, lamb, pork, venison, etc.) sous-vide for a long time (8 hours or more) at a temperature below 60C/140F, sometimes the meat comes out with an unpleasant smell. Sometimes just faintly, sometimes very strongly. The bag may even be puffed up a little. I already looked into this problem several years ago, and wrote a post about it. But I did not really solve the problem back then. Luckily, now I seem to have solved it!
It is mentioned in many sources online that this problem is caused by lactobacillus. This is a type of ‘good’ bacteria that are not harmful and they are actually used to make cheese, yogurt, sauerkraut, and sourdough bread. It is known that they can reproduce up to a temperature of 59C/138F, so it is not surprising that they are not killed when meat is cooked at temperatures between 55C/131F and 59C/138F. It is also not surprising that the smell is somewhat reminiscent of stinky cheese (as lactobacillus is what makes the cheese stinky, too). By the way, from a food safety perspective it is safe to eat the badly smelling meat, as lactobacillus is harmless (people even buy expensive types of yogurt to eat the lactobacillus on purpose). You may not just enjoy it as much.
What is also mentioned in many sources is that lactobacillus can be killed, and the funky smell prevented, by searing the meat before vacuum sealing. This seems to make sense, because searing will kill any lactobacillus that are present on the surface of the meat. However, I tried this and it didn’t work. In fact, over the seven years I have been cooking sous-vide, I have had several occasions where pre-seared meat still ended up with the bad smell. So how is that possible?
In the meantime, I have learned more about lactobacillus. The most important thing I’ve learned about lactobacillus is that it is (or at least can be) all around us. The process of making a sourdough starter illustrates this: you just mix flour and water, and ‘out of nowhere’ lactobacillus will start doing its magic. This why searing the meat and then vacuum sealing doesn’t always work, because after searing the meat can be infected again by lactobacillus before you vacuum seal it!
Once I had realized this, I had a theory of what would work: vacuum seal the meat first, and then scald it in boiling water for about 20 seconds. The scalding will kill any lactobacillus that was on the meat when it was vacuum sealed, and because of the vacuum seal there is no way that new lactobacillus could get in again. I put this theory to the test, and it works! After repeating the results with another type of meat, I am now confident enough to present this solution to the world.
For the first experiment I started with a piece of lamb shoulder.
I cut this into two pieces and seasoned with salt and pepper.
Then I vacuum sealed both pieces separately. One of the bags I marked “SCALD” and I scalded it for 20 seconds in boiling water. This brief scalding will affect only the surface of the meat.
As you can see the two pieces of lamb shoulder now looked very different.
After cooking them for 48 hours at 57C/135F, they looked more alike…
…especially after taking them out of the bag. The scalded piece smelled of lamb, the un-scalded piece had a bad smell and was discarded.
After this I proceeded as usual with the scalded piece of lamb and seared it in a frying pan over high heat.
I repeated the experiment with a chuck steak, cooked 72 hours at 55C/131F. Again the scalded beef was perfect, whereas the un-scalded beef came out with a bad smell.
So from now on, I will always scald in boiling water for 20 seconds after vacuum sealing when I’m cooking meat below 60C/140F for 8 hours or longer. (I have never had a problem with short cooks, probably because the time is too short for lactobacillus to grow significantly.) You can sear the meat before vacuum sealing it, and then you still need to scald it anyway.
It is important that the surface of the meat is touching the bag everywhere so that the scalding can kill all lactobacillus. In other words, if vacuum sealing multiple pieces in one bag then make sure they are not touching each other.
Instead of boiling water, you can also use water that has been heated to 77C/170F, as that is also hot enough to kill bacteria instantly. However, I find it easy to use boiling water, because I can tell it’s boiling by looking instead of using a thermometer.
Stefan's Gourmet Blog 
Excellent and very useful information. Thank you very much!
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When one makes beef jerky in an oven you should always preheat the oven to 175 and put the beef in for 10 minutes before lowering it to 170 or lower depending on you oven. Same principle applies to sous vide to kill bacteria.
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it wont work with short ribs, way too much surface area for the scald.
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I’m not sure what you mean. If all the surface area is in contact (with plastic in between) with the hot water, it will work.
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Short ribs are cubes, unless in separate sous vide bags. Or how do you get the sides of 4 short rib cubes blanched without boiling for minutes to heat the abuting ribs.
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Yes they should be in separate bags or if they are in the same bag there should be space in between in order to make sure all of the surface area is on the outside.
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Nice one! Makes perfect sense. I’m gonna try your approach and see how it goes. Time to buy a microscope! 🙂
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https://ourdailybrine.com/sous-vide-salami-fermentation/
the opposite idea
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I wonder if you have to go that high on temp to kill the bacteria? Seems 212f could compromise the seal of bag and alter surface of meat more than necessary. I wonder if maybe 170f would be high enough to kill bacteria?
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Hi Kevin, you don’t have to go that high and 77C/170F would indeed be enough. I only use boiling because it is easier as I don’t have to use a thermometer, and because the vacuum bags I use are heat resistant up to 115/239F. I’ve updated the article accordingly. Thanks for your comment.
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Is there any way to eliminate the smell once it’s already been cooked?? I have a batch of short ribs that I didn’t scald ahead of time and am trying to figure out how to fix them now??
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I am sorry but I do not think it is possible to eliminate the smell once it’s there. Searing and strong spices may reduce it, but not eliminate it. It is still safe to eat, but it may not be enjoyable.
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I have never had a problem with stinky meat in the sous vide, but I also have never cooked meat that long that low. However, this is VERY useful to know if I ever do!
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You’re missing out! Please try short ribs 48 hours at 135 degrees (and make sure to scald after vacuum sealing). I am assuming you like your steak medium rare.
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Yes, yes we do. Now that my food cart is closed for the season my sous vide circulators are freed up for home use. I will certainly try this!
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Any change on your electric bill? the first month on my sous vide cooking, i experimented long cooking ribs , and other cuts of meat, my bill quatripled that month
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That can’t be from the sous vide cooking, unless you did not insulate the container at all. If you use it constantly, it will still not cost more than a few dollars per month in electricity.
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*huge smile* Of course I know another way to avoid that possible smell . . . . sorry, Stefan: sometimes one’s resistance is low . . .
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Thank you, Stefan, for sharing your results on your blog.
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What fine forensic cooking!
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Excellent experiment Stefan. That looks like a simple solution.
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Hi Stefan,
I have enjoyed your blog tremendously. As my sous vide bags are only rated to about 180F, do you think an immersion in 170F water for a bit longer, say 2 minutes, would accomplish the same result?
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Hi David, yes that should work too. At 170F probably even 30 seconds should be enough as you just need the time for the heat to get through the plastic and then it will take only a second to pasteurize the outside. I mentioned boiling water because it is much easier than hearing up a water bath to an specific temperature.
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Hi Stefan
I have been using your hot scald method ever since I read you article, works every time thanks, I want to freeze some half strip loins on sale for roasting at a later time. I would assume I can vacuum pack and scald the packed roasts and then freeze would this be ok or should I also still scald before I Sous vide the frozen meat.
Thanks
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Hi Chris,
I’d scald after freezing.
Glad to hear you like my article.
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Outstanding information! I have wondered at times about negative long-process results others have had. I did a large [~11lbs/~5Kg] 3-bone beef rib roast for 16+ hours at 133F/56.1C then seared it under a broiler to brown. I had no bad smell so I suppose I was lucky. Will be doing pork ribs for 48-72 hours soon then hot smoking for a Texas BBQ experiment. I will scald them first. Thanks for the tip.
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Very useful thank you
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Thank you for the information in you post. Excellent info it’s great that you shared. Though i must say in all my time doing long process sous vide I have never had that smell you talk about. (I can see it now having said what I said I maybe tempting providence😂) Maybe a discussion from people who have had the smell and where they live in the world, It maymight be the feed the the animal eat?? I have sous videed in UK and the Canary Islands.
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I’m pretty sure the contamination happens at the butcher’s or in your kitchen. Some people also notice the smell more than others. I have a friend who can’t eat anything that has the faintest whiff. I only rarely had the smell such that I didn’t want to eat it. But now I always blanch to avoid it altogether.
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What about a shot of whiskey in the bag?
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Supposedly alcohol doesn’t work well with sous-vide, but I haven’t tried that myself. When cooking at temperatures above the boiling point of alcohol (78C/173F) the bag will float, but that is not an issue of course when cooking below 60C/140F.
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Would it work to scald the vacuum packed meat after the sous vide cooking process? Is the sm
ELL just from the surface of the meat?
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Hi Karen, the lactobacillus will grow during the cook if you do not scald the vacuum packed meat before the sous vide cooking. Scalding afterwards may slightly reduce the smell, but will not eliminate it. The smell is indeed just from the surface of the meat, but it can sometimes be so pungent that it is difficult to remove once it has been allowed to develop.
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Excellent suggestion. I was wondering if rubbing the meet with vinegar, as an ingrediente of a wet rub, will help control the funky smell since vinegar is supposed to help kill bacteria.
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Vinegar doesn’t kill all kinds of bacteria and lactobacillus actually make lactic acid themselves, so I doubt it.
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“meet” in my previous comment equals protein.
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Thanks for your answer.
One last question: would preheating the water bath above 145 degrees prior to submerging the protein and letting the protein sit at that temperature for an X number of minutes before lowering the temperature to the recommended “cooking temperature”; would this work?
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X would be at least 4 minutes at 145 degrees. I don’t know how much the transfer of heat is slowed down by the plastic. Afterwards I would recommend to lower the water temperature quickly using cold water. So yes that would work but just dumping in boiling water is easier I think.
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yeah i just cooked some ribs at 57C for 48 hours and opened the bag and threw up the smell was so rotten! should have read this first!
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Will you try again using this technique?
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I just finished cooking a pork shoulder butt using the technique we discussed and it worked,
Thank you for helping sous Vide land smell better.
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I’ve done it before and the smell was so bad I just couldn’t bare to eat it.
Another issue is that even with tight vacuum sealing, cooking at 55°C also results in the bag bloating up and becoming a balloon. Any tips for this?
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The same solution should help for that as well. Unless you put other stuff in the bag that causes the bloating? If you put meat, salt, pepper and scald the bag after vacuum sealing, there should be no bloating.
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Great, I have to test that.
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I have found that cooking pork ribs at 165 F, 18 to 24 hours renders tender ribs and great taste.
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I agree. At that temperature you don’t have the bad smell. An alternative, also very good, is to cook pork ribs at 135F for 24 hours. The texture will be very different (not ‘pulled’ or flaky), but for that temperature you do need to scald in boiling water to prevent a bad smell.
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Also, I have raise the water temperature about 150 F Stephan suggested 145–I just wanted to compensate for the drop in temperature once the protein is placed in the container. After 10 mins, I lower the temperature to the recommended temperature for the protein–also, adding ice to the water to lower the temperature faster is a good suggestion, but I have yet to find a need to do that. After all, what is 15 or 20 mins on on something that might be cooking for more than 10 hours.
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I found this blog because I was “researching” if I should expect to visit the ER in the next few hours. I sous vide pork ribs for 72 hours at 62C, the comments sounded worth the effort. The smell is pervasive throughout the house, ate one rib and threw the rest out. While I like meat to be tender, I also like it to have some texture. Thank you for the information about the bacilli, maybe I’ll watch some TV instead of heading for the hospital. I certainly will never again make 72 hour pork ribs and if I do any slow cooking it will be in addition to the 30 second boiling water trick. Thanks.
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I have never heard of or experienced this above 60C, but I assure you the boiling water trick will take care of it. Next time you do pork ribs, 48 hours at 57C will be a much better choice. The meat will be tender but more juicy and better bite than at 62C.
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I did a 6 lb chuck roast in triple bagged ziploc freezer bags and only got a very faint smell which I’m not even sure is the smell being discussed here. COuld it be that my generous salting on the surface killed or impeded the lactobacillus?
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Note: I cooked it for 48 hours at 135F
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Yes that is possible, but it would have to be very generous.
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Hola Stefan! Thanks for the article, I have had this happen to me twice in a row, the first time I started with steaks straight out of the freezer, vacuum sealed them and did a 4 hour Sous vide, resulting in tenderness but stinky. Tried it again with thawed steaks, same result. I am going to try your method, but was wondering if you think that if I scalded the frozen vacuum sealed steaks for 45 seconds or so would be sufficient to kill the bacteria. I originally thought (incorrectly) that the frozen steaks would have no bacteria issue but now I’m not sure. What are your thoughts? Thanks again.
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There are two reason why freezing does not help. First, freezing doesn’t kill bacteria, they only stop growing. Second, the lactobacillus are everywhere and so the steaks can be contaminated before you vacuum sealer them. I think scalding for 30 seconds would be plenty for the frozen steaks, as the lactobacillus are on the outside, not the inside.
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Thank you. I was wondering why my beef ribs were so stinky.
I wonder if your solution would work on blade tenderized meat, such as the beef sold at Costco. Have you tried the technique on beef from Costco?
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I have never tried it with blade tenderized meat. If the blades are contaminated with lactobacillus, the solution would not work. With sous vide you don’t need blade tenderized meat anyway.
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I just cooked 2 bags of confit duck legs at 155 f for 36 hours. I add the offal without the livers. One bag smelled funky. Almost like ammonia. First time this has happened. Any idea why?
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I’ve never had funky smells above 140F. If it smells like ammonia, I wonder if there was a long time (multiple days) between vacuum sealing and cooking? Or it could be the offal – did you include the gizzards without cleaning them?
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Yes, I’m thinking it was the offal. They immediately went into the water, so it wasn’t the time. I usually just throw the heart and other triangular pieces right in from the bag. Never occurred to me to clean them. Do you do anything but rinse? Thanks for taking the time to answer
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I do rinsing and visual inspection. The innards may still contain “stuff” that you don’t want to eat. When in doubt, I don’t include a part of the offal that I’m not sure about. The heart should be fine. The gizzard should also be find but may need rinsing and/or scraping. The intestines you want to discard.
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Very interesting!
I’m new to sous vide and only have freezer bags. Still trying to decide on a decent vacuum sealer then need to save up for it.
Will this work using freezer bags? Also, will a freezer bag withstand a long (24-48 hr) bath? I was going to try a chuck roast @135…. time still undetermined.
Thank you!
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Hi Keith,
I’ve done a few 3-4 hour chicken cooks in freezer bags. they hold up pretty well for that period, but I am unsure if the freezer bags would hold up for the day-long cooks. I would at least try to double bag them just in case. Additionally, I find the greatest leak risk with freezer bags are the corners of the zipper. Even when using my best Ziploc freezer bags, I occasionally get water seepage through these points. For that reason I now try to attach the bags to the rim of my container when using freezer bags.
Side note: I love doing big chuck roast 2-day cooks. I use 131 degrees since I prefer as rare as possible (131 is the lowest I’m brave enough to do for a multi-day cook) I think the results are great. You get somewhat of a roastbeef/prime rib texture. Especially for larger pieces of meat, I find that a decent crust of salt on all exposed surfaces of the meat prevents the funk that this thread was created for. On thinner pieces of meat, it just makes things to salty. Best of luck on your cook!
– Daniel
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NOTE: I do my 2-day cooks in vacuum seal bags, not in freezer bags.
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Hi Keith, instead of boiling water you could also use water that is at least 170F, which will be safer for the freezer bags. Boiling water is easy because you know it’s hot enough without using a thermometer. At 135F the 24-48 hour bath will be fine, but it is a good idea to attach the top of the bag using clothes pins or something similar. At higher temperatures the longer cooks may be more problematic, but it depends on the thickness of the bags.
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I’ve had some bad luck with boneless short ribs lately – 72 hrs @129 the first time and 72 hrs @132 the last time. Both times the result had a very off-putting smell, it definitely smelled more like rotten meat than the sharp ammonia smell I get from spoiled brie, on both occasions, but the bags that ballooned up slightly were definitely the worse of the bunch. I’ve just about given up on this long medium rare cook. I’ll try one more time with this technique and see if what I’m smelling was in fact lactobacillus. Meat was costco prime short ribs, (which I don’t believe are blade tenderized — I’ll have to check more closely next time) pulled right out of the cryopac, rinsed salted and peppered, bagged in foodsaver bags and well within the expiration date… Thanks for posting your solution!
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That does sound like the lactobacillus problem, both from your description of the smell and because you have ruled out other issues. If it is bad it also makes the bags balloon.
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Thanks for posting this research. Your results explained the sudden problems I recently encountered, first with Costco beef cheeks (48 hours at 131F) followed immediately by a Piggly Wiggly pork butt (52 hours at 135F). The beef cheeks were incredibly nasty, and the pork butt will be consumed (happily) only by my eats-all-rotting-things dog.
Previously I’d never experienced this type of problem. Your solution seems like an excellent approach. Now I wonder if hot smoking or flame searing would also solve the problem. (Of course, you gotta wonder…)
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Hot smoking or flame searing (BEFORE cooking sous vide) does help, but it does not always completely prevent the problem. This is because after smoking or flame searing there is a risk that you infect the meat with lactobacillus again (which is everywhere in your kitchen) before vacuum sealing. This has actually happened to me a couple of times. Killing the lactobacillus after vacuum sealing is the only method that guarantees you won’t have the bad smell.
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Thanks for this info!! I like my meat rare so I always cook at low temps. I’ve been having this problem for a while and it changes the flavor of the meat in addition to the smell. I’ve always eaten the meat and haven’t gotten sick. I just assumed the meat was fermented.
I don’t like using plastic so I use silicone bags to sous vide in. The ones I used didn’t seal and I would just hang the top over the side, so I suspected bacteria was getting in. I first tried a higher temp, 135F, and that didn’t work. I then tried a sealed silicone bag and that didn’t work either. Now I know why!! I will probably start the sous vide at a higher temp and lower it to prevent this. Not sure the scalding will work as well in silicone bags. I will also be sticking with the sealed bags.
I have smoked meat prior to sous vide and didn’t have an issue with smell or taste change from bacterial growth.
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Hi Sabrina, make sure you do the sous vide at the high temperature very briefly, because otherwise a large portion of the meat will no longer be rare.
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This problem happened to me a few times and I decided to look into it this past Saturday. Thank you for this article I know the brisket was not harmful, but I didn’t want to eat the rest of the brisket and had to throw it out.
I usually get a whole piece of brisket, I would cut/divide/salt/pepper/vacuum/freeze it right the way. Whenever I need to have brisket, I just take it out from freezer and throw it into the sous vide.
I am curious will the 30 seconds hot water rule work given the package is frozen? If not, should I do this longer or I will have to thaw the meat first, 30 seconds hot bath and then sous vide?
Thanks.
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What I would recommend is to cook all of the brisket sous vide (giving it the hot water treatment, obviously) before freezing it. This saves on energy (if you use a sous vide stick and a large container, you can cook a lot of brisket at the same time for the same amount of power as cooking just one piece) and freezing doesn’t cause as much damage to cooked meat as it does to raw meat. If you do want to freeze it raw, I would recommend to apply the hot water BEFORE freezing, and then chilling in ice water after the hot water step.
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i have 25kg of chuck cooking at 131f 48 hours, there is an odd smell i have 12 hours left to go and change the temp to 141f will i be able to save the meat
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I’m sorry. Once the smell is there, you can’t get rid of it anymore by increasing the temperature or even by searing. 25 kilos?! Sounds like an expensive lesson 😦
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Sorry to hear that. It is an expensive lesson as Stefan pointed out. Also, most manufacturers of sous vide machines claim that their equipment could have a 1 +/- degree variance from the displayed temperature and since I am not brave enough to cook any protein below 132 that is my minimum temperature choice.
Cheers!
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Stefan,
Great blog post. I’m trying to find evidence in the scientific literature to support that Lactobacillus can grow our temperatures as high as 131 °F, But I’m not finding it. It does very much seem like it is some sort of a spoilage organism, but not Lactobacillus.
Can you provide any sort of a link to documentation that would show that lactobacillus can grow at 131°F? Thanks in advance.
– Don
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Thanks for the advice Stefan! What would you recommend if I’m sous vide cooking a piece of meat that has to be rolled (like a pork shoulder or pork belly)? Should I scald it once unrolled in hot water and then scald it again once I’ve rolled and vacuum sealed? Or should vacuum sealing and scalding the rolled meat be enough? Also does any sort of preparation before vacuum sealing (quick soak in vinegar water or water with baking soda) have similar effects?
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Great info. Thank you!!
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