This is a bit of a strange question, but may a small amount of soap or detergent be placed in the water when cooking with sous vide? Is the vacuum effective enough to prevent any taste of soap from entering the food contents? Thank you

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    If the bags seal well enough for vacuum they will deal well enough to keep the soap out. I'd be more concerned about contaminating the food when you open it (though you could rinse). Why would you want to do this though? It sounds almost like you're trying to combine cooking and washing up in one process.
    – Chris H
    Feb 25 '18 at 7:53
  • Thank you for the response. There may be a secanrio where this could serve as a solution for those who observe kosher dietary laws. That is why I am trying to figure out if it is a viable option. Clearly the bag would need to be rinsed prior to opening to avoid contaminating the food. Feb 25 '18 at 14:19
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    That's interesting - it didn't cross my mind. I assume in that case the alternative is two sous vide units, but my understanding is limited at best. The bags are meant to be impermeable, but I reckon most people would hesitate to say yes. In your position I'd test it on myself with some very plain food that would reveal a contaminated taste, combined with a much stronger soap solution.
    – Chris H
    Feb 25 '18 at 16:41
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    The water temperature of the rinse may also be important to the end result, depending on the next step in the cooking.
    – Chris H
    Feb 25 '18 at 16:42
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    Curious, in what way kosher laws have to do with a cooking technique ?
    – Max
    Feb 26 '18 at 15:05

I'd be concerned with two things here.

First of all, I'd be concerned that some soap might contaminate the food product without you knowing about it. If it's a low enough concentration of soap that it would not cause significant harm to ingest, this isn't a big concern; on the other hand, I might be inclined to use something other than actual soap that is able to accomplish the purpose here if that is possible - for example, a mild bleach solution (I've also seen "pool shock" suggested) might be safer. Do some research on whatever you add to make sure it's actually okay for this purpose. If your purpose is to remove bacteria, this is probably your best bet.

Second, I'd be concerned with odors from the soap affecting the food being cooked. Even if the soap never contacts the food, the odors that make the soap smell good are much more likely to affect things in my experience. If you do use soap, use an odorless soap (something like original (blue) Dawn, no endoresement suggested).

If you can edit the question to provide more of an explanation as to why you're asking it (you mention Kosher laws, but not the specific issue you're trying to address) you may get a better answer.

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    Potentially ingesting bleach is better than soap?
    – mattm
    Feb 26 '18 at 17:14
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    @mattm Yes (at low concentrations). Bleach water is used as a disinfectant commonly in food service in cases where the bleach is not later rinsed off (three compartment sink, right?); pool water is more-or-less bleach water, and chlorine is in the water you drink from the city if you're in a major city or most smaller ones. Mostly, bleach needs waaaaay lower concentrations to do anything useful, evaporates at room temperature reasonably quickly, and dissolves well in water; soap would need a much higher concentration to do anything useful such that it would make you sick.
    – Joe M
    Feb 26 '18 at 18:35

This depends on the bag used. Most zip style bags are not impermeable. Whether or not a soap flavor or aroma molecule is large enough to permeate is something I do not know. However, as suggested in the conversation above, you can use a vacuum sealer, and the appropriate bags (more impermeable) to seal a bag within a bag. I think you would be good to go in this scenario.


If you really want to be sure, then use a retort bag to vacuum seal the food. The retort bag is not gas permeable so you don't have to worry about any soap aromas affecting the food.

Retort bags are usually made from multi layer laminated plastic sheeting designed specifically to be gas impermeable and heat resistant.


I would say that even vacuum-sealed bags are not 100% non-permeable. I say this because I have noticed that during very long sous vide baths,like a 48-hour cook on full briskets in vacuum sealed bags, I can smell the meat cooking after about 24 hours. No leaks in the bags but still smelling the brisket. Curious but real.

Therefore, I would hesitate to add soap or any other product to the water bath...especially if the bag were to lose the seal completely. Recoverable if caught quickly but not if there is foreign matter in the water.

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