I know that the 18 minute thing is up for debate (time for 1 mil, whether continually working dough can indefinitely extend it, temperature dependence etc.), but at what part of the process can a dough no longer become chametz? When it completely finishes baking?

If something becomes chametz through fermentation, I would guess that once the microorganisms are dead it can no longer become chametz, but that understanding of fermentation is a relatively recent thing, so how is it normally defined?


Shulchan Arukh OC 461:3

מצה שנאפית עד שאם פורסין אותה אין חוטין נמשכים ממנה יוצאים בה: הגה: ויש ליזהר שלא ללקחה מן התנור קודם לכן ולהחזירה כי תוכל לבוא לידי חימוץ

Matza that was baked until if you cut it no strings of dough pull from it, one fulfills his obligation with it. Gloss: and one should be careful not to take it from the oven before then and return it because it may come to ferment.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .