Why is it generally assumed that hot water on an airplane is kosher? Is the urn that warms up water on an airplane strictly for water use? Or do they alternate and it can be used sometimes for other things? My question is also: is that urn ever washed with other traife kaylim (nonkosher utensils)?

  • This doesn't seem to be a Judaism question, but rather an airline policy question. Other than El Al, perhaps, I'd be surprised if any airline has a mashgiach on any level at all. There's no requirement for them to have one. Each airline can establish its own policy. Surmising, the urns probably aren't used for anything other than hot water or coffee. However, once they are removed from the plane and washed, anything can happen, and I doubt any mashgiach knows what really happens.
    – DanF
    May 28, 2018 at 0:49
  • I think this would be greatly improved if you’d explain things like why it would make a difference what else it’s used for, and why it makes a difference if it’s washed with treif keilim.
    – DonielF
    May 28, 2018 at 1:17
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    cause if it was washed with other traife things in hot water then I wouldn't want to use the hot water for my kosher coffee
    – user17545
    May 28, 2018 at 2:03
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    IMO this question is clearly on-topic. The on-topic list includes explicitly questions of science etc that relate to Judaism. (Because of technical difficulties I cannot look up the exact wording now.) We've always had such questions.
    – msh210
    May 28, 2018 at 3:24
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    Comments that seek clarification are intended to elicit explanatory edits to the post, and are never intended to elicit further comments. Comments are ephemeral by design and can be deleted at any time.
    – msh210
    May 28, 2018 at 3:25

2 Answers 2


I have been flying nearly every week for 20+ years. I cannot recall having seen the hot water urns on planes used for anything else than hot water, tea or coffee (note many airlines prepare coffee directly into the urns). They often have a spout that would only work for liquids anyway.

Regarding the kashrut of hot water on planes (the title of your question), many sources allow drinking tea and coffee on planes, e.g.,

  • dinonline (here, #65) writes "a hot water urn or teakettle may be used without kashering. You may presume it was used only for water and is thus permissible, unless you know for sure otherwise."
  • R Tsvi Heber from COR (kashrut hekhsher) writes "Urns and kettles may be used year-round ... year-round [but not on Pesach] it is permitted to drink unflavoured coffee that has already been prepared for the office"
  • OU Kosher writes "Rav Belsky said, in general there is no concern that the utensils that cooked the coffee were used with non-kosher. The coffee pot is usually rinsed out and reused, and is not sent through the dishwasher. Rabbi Schachter added that there would be reasons to be lenient even if the coffee pot was sent through the dishwasher."
  • R Yaakov Goldstein doesn't worry about the kashrut of the water but writes here regarding those who are stringent because of bishul akum

See also this related question on MY.


Even if the utensil was indeed used for non-kosher liquids, or washed together with non-kosher utensils, it could only affect the use of hot water put inside afterward if it was used with non-kosher within 24 hours of the current hot water use.

See Shulchan Aruch YD 122:6 Stam keilim einam bnei yomam - If we don't know, we assume that utensils were not used [for non-kosher] within the past 24 hours.

  • Within 24 hours is still assur deRabannan. Your answer doesn't address any leniencies that could be relied on.
    – robev
    May 28, 2018 at 17:38
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    @robev WRONG! Recheck your sources: If kosher food was cooked in a non-kosher pot which is aino ben yomo, not used for non-kosher within 24 hours of the kosher cooking, the food is permissible to eat B'dieved (after the fact) even M"Drabanan, because the taste of the non-kosher food which enters the kosher food via the walls of the pot is Nosen taam L'pgam gives a spoiled taste. If we don't know, we assume that utensils were NOT used [for non-kosher] within the past 24 hours. So no issur, Bdieved even m'drabanan. May 29, 2018 at 7:42
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    @robev what is your source that "you can't plan" to eat food which was already cooked in a aino ben yomo treif pot, if it wasn't done specifically for you or upon your request? May 29, 2018 at 12:20
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    Is that really called bedieved? I'm just saying it's not as pashut as you make it seem. Otherwise all the poskim in the other answers are wrong... Also a plane might be worse as you're paying them and included in that is food/drink.
    – robev
    May 29, 2018 at 12:32
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    A bedieved case is it was cooked in the pot without your foreknowledge and then you can eat it. Here, you knew ahead of time it would be cooked in it, for your eating/drinking convenience. We're disagreeing if that makes a difference.
    – robev
    May 29, 2018 at 13:15

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