Menachem Mendel

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What’s With Those Eighteen Minutes

Many of us have heard that from the minute water touches the flour, there are only eighteen minutes within which the baking of matzah must be finished. Well, it is actually a disagreement among halakhic authorities. According to some, the eighteen minutes is the maximum amount of time that the dough can sit without it being kneaded and not the time within which it must be cooked. Here are some of the sources. I don’t have time to translate them, so my apologies.

שלחן ערוך או”×— תנט:ב

לא יניחו העיסה בלא עסק ואפילו רגע אחד. וכל זמן שמתעסקים בו, אפילו כל היום אינו מחמיץ; ואם הניחו בלא עסק שיעור מיל, הוי חמץ. ושיעור מיל הוי רביעית שעה וחלק מעשרים מן השעה. ×”×’×”: ויש להחמיר למהר בענין עשיית המצות, ×›×™ יש לחוש שהשהיות יצטרפו לשיעור מיל, או שיהיה במקום חם שממהר להחמיץ…

באר היטב ס”ק ×—


2 Responses to “What’s With Those Eighteen Minutes”

  1. 1

    What you wrote is not accurate.
    What the SA writes is that if flour and water are left (without any kneading) for ~18 minutes it is considered chametz. However if the dough is kneaded, then as long as it is being kneaded even all day long it does not become chametz (and on this the baer heitev brings that it should not be kneaded for longer than ~72 minutes!). On the other hand, if the dough was kneaded, after the water was poured into the flour, and then left without being worked with, it does not need 18 minutes but is considered chametz immediately.

  2. 2
    Menachem Mendel:


    I am not sure how what you said is different than what I said.




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