The Halachic principle of Kavush states that leaving something in liquid for 24 hrs transfers taste, and therefore it alters the status of the thing with which it is exchanging tastes.

However, anything left for 24 hrs is considered Nothein Ta'am Lifgam, which means that it transfers only bad taste, and it therefore doesn't alter the status of the thing with which it is exchanging tastes.

So how does Kavush work, if leaving something for 24 hrs makes it N"T Lifgam?

  • I thought it's only N"T lifgam if the absorbed taste was isolated from actual food and sitting in the k'li for 24 hours, i.e. the clock starts when the food is cleaned from the surface. If it was just exposed to actual food (in liquid form), you can't expect it to be NT lifgam instantaneously.
    – Fred
    Feb 10, 2013 at 18:47
  • @Fred, maybe that's the answer. But isn't residue also N"T Lifgam? Oil residue on a plate, the two drops of juice at the bottom of the cup? An ounce of curdling milk in a bottle?
    – Seth J
    Feb 10, 2013 at 18:50
  • See section #3 here: "The Ramban states that the principle of "natlap" may also be applied to food residue. As long as twenty-four hours have passed, the residue on the plate is deemed "pagum" (defective) and the food cooked in this utensil is permitted. The Raavad and other Rishonim disagree. They maintain that only the ta'am absorbed in a pot twenty-hours after its last usage will cease to positively enhance a mixture. We cannot assume, however, that the same holds true for non-kosher food residue."
    – Fred
    Feb 10, 2013 at 19:09
  • ... I think there's a distinction between old food and mere residue, though.
    – Fred
    Feb 10, 2013 at 19:11
  • I think the Taz asks this question in Yoreh Deah 105:1. I'd have to look it see for sure.
    – Menachem
    Feb 10, 2013 at 23:56

1 Answer 1


As a matter of halachah, the rule that after 24 hours flavor becomes pagum is reserved for flavor absorbed in a pot or slight residue on its walls; not actual food.

(Shulchan Aruch YD 122:2-3 and Aruch Hashulchan ad loc.)

  • So... Curdling milk that's totally shnasty is food?
    – Seth J
    Feb 10, 2013 at 20:05
  • See YD 103:5 regarding slight residue on the walls. According to Rama it does not become pagum after 24 hours.
    – Michoel
    Feb 10, 2013 at 21:46
  • 3
    Rotten milk might be pogem even before waiting 24 hours!
    – Double AA
    Feb 11, 2013 at 3:14
  • 1
    @SethJ I said "the rule that after 24 hours flavor becomes pagum is reserved..." You were asking about the rule. Of course, anything which you know is pagum, is pagum. Shnasty curdling milk included. This is YD 103:1. But this has nothing to do with the 24 hour rule, which is when you don't have something totally shnasty in front of you.
    – Dov F
    Feb 11, 2013 at 20:43
  • @Michoel See the Aruch Hashulchan I cited who explains that the Rema is talking about significant, not slight residue.
    – Dov F
    Feb 11, 2013 at 20:45

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