Let's say a pot of raw dry oats becomes fully cooked in 5 minutes. Just oats and water. How is it considered chometz?

  • 1
    why would it not be chametz? (assuming oats are one of the 5 grain)
    – Double AA
    Nov 27, 2012 at 17:41
  • Are you heating this pot, or just soaking the oats in cold water?
    – Double AA
    Nov 27, 2012 at 18:14
  • related judaism.stackexchange.com/a/12898/759 I'm not sure even that the 18 minute rule (if that's what you refer to) applies to all 5 grains in all their forms. It could be different consistencies and whatnot affect the time it takes to become chametz.
    – Double AA
    Nov 27, 2012 at 18:18
  • What about oatmeal cookies where you basically make matzo EXCEPT using whole oats in lumps rather than ground oats in sheets? Why is it chometz before cooking?
    – A L
    Nov 27, 2012 at 21:24
  • Can you describe these oatmeal cookies in more detail?
    – Double AA
    Nov 27, 2012 at 23:42

2 Answers 2


The Shulchan Aruch (OC 555:3) rules that if one kneaded his dough with hot water it is forbidden, the assumption being that heat makes something become chametz quicker. This is also seen in the rule (559:1) not to knead the dough in the sun or in a room with a hot oven. Moreover one can leave dough in cold water indefinitely to prevent its becoming chametz (557:2).

  • Assuming the question means cooking with heat.
    – Double AA
    Nov 27, 2012 at 18:20
  • You can't kneed in hot water because by the time you're ready and cooked you're over the limit. I'm not asking about that. 5 minutes of hot water and oats in a pot is a lot less than 18 minutes of hot water and oats in an oven.
    – A L
    Nov 27, 2012 at 21:22
  • 2
    The whole point is that the 18 minutes (if that's what you're talking about; I don't see it in your question) is shortened when working in hot environments because things ferment quicker.
    – Double AA
    Nov 27, 2012 at 23:43
  • Of course, this is probably more accurately a case of Chalita which the Geonim forbade on Pesach (ShA OC 454:3)
    – Double AA
    Apr 6, 2017 at 14:44
  • Why does it make a difference whether the heat is during the kneading or after? (Besides, matzah factories are pretty hot, or at least the ones I've been to.)
    – DonielF
    Apr 6, 2017 at 14:47

Per OU.org

Similarly, all oats are heat-treated to prevent them from becoming rancid; if this heating is done with “wet” steam, the oats/oatmeal may be chametz


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