Why don’t we use halachic hours to calculate how long you should wait in between eating meat and milk or vise verse? This would make a significant difference in different seasons like winter and summer in regards to how long one has to wait between the two.

How come today then do we calculate in regular hours and not halachic, regardless of the biology of it?

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    – Double AA
    Commented Mar 29, 2019 at 2:55
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    Kaf HaChaim says explicitly not (Yd 89)
    – Dr. Shmuel
    Commented Mar 29, 2019 at 11:10
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    @mroll Has any scientific evidence shown that any of the popular opinions on waiting time correlate with such biological functions?
    – Alex
    Commented Mar 29, 2019 at 16:11
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    @Alex, 6 hours is the minimum waiting time required to avoid the risk of vomiting before anestesia.
    – Yishai
    Commented Mar 31, 2019 at 2:26

1 Answer 1


Interestingly the Pitchei Tshuva on SA YD 89:1, in the context of eating meat after milk, brings an opinion from Beer Heitev shel Maharit that these could be shaot zemaniot. He quickly writes the Pri Megadim, Hokhmat Adam and Knesset Hagedolah disagree and the minhag is not to use shaot zemaniot.

עבה"ט של מהרי"ט ז"ל אם הם שעות זמניות. ועיין כו"פ ופמ"ג ובחכמת אדם שהסכימו לדעת הכנה"ג דאינם זמניות ע"ש וכן המנהג.

The Pri Megadim brings the Knesset HaGedolah who writes (my translation - feel free to improve)

והני שש שעות הם חלק מכ"ד מעל"ע לא זמניות וכ"כ הכה"ג בהגהות הטור אות ו' דוודאי אין לומר בימות החורף מתעכל מהר והוא פשוט:

The six hours are part of the 24 from time to time and are not shaot zemaniot and so wrote the Knesset HaGedola [...] that of course we cannot say that in the winter we digest faster and that is simple (obvious?)

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    It isn't at all obvious that digestion speed is relevant. The Gemara doesn't say that. The Gemara just says somebody waited the time between meals, which is something that definitely changed with the seasons. צ"ע on the Pri Megadim.
    – Double AA
    Commented Mar 31, 2019 at 15:18
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    I’m not sure if you are arguing on the PM or what I wrote. I was just trying to answer the question on whether we could use shaot zemaniot. A number of poskim say we can’t because of what mroll intuited in the first comment ie digestion doesn’t move faster depending on season
    – mbloch
    Commented Mar 31, 2019 at 15:27
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    I'm just pointing out such a claim has no classical basis and is contradicted by the simple read of the Talmud. It could indeed be the reason most popularly given, but we shouldn't just take it as obviously reasonable because you've heard it before. This idea that digestion is relevant is a major Chiddush. A waiting time is more simply understood as an artificial Hefsek to prevent any mix-ups.
    – Double AA
    Commented Mar 31, 2019 at 15:30

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