r/Judaism • u/Complete-Proposal729 • 1d ago

Halacha Siur, sidduk and chametz

In the Talmud there’s a description of the stages of dough turning into chametz, namely siur and sidduk.

There is some disagreement on exactly what is what at each stage, but overall the process is described as

  • Dough turning pale (like the color of someone’s face when their hair stands on its end due to fear. This may be the criterion for siur

  • When cracks form that look like locust antenna. This may be the criterion for siur

  • When the cracks intermingle…this is sidduk.

So when cracks intermingle, that is sidduk and thus full chametz. Does anyone have photos of doughs that exhibit this behavior, so we can see each stage?

How long approximately in standard room temperature does it take to reach each stage for an unyeasted dough without a sourdough starter like se’or?

Thanks!

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u/Thebananabender Secular Mizrahi Jew 1d ago

Generally, the time the dough is still not hametz is 18 minutes (or mil= the time it takes to walk a mil which is roughly a kilometer)

So 15 mins or so is just fine.

Fur the accurate stages, some say that the second stage happens some time later after 18 min…

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u/Complete-Proposal729 1d ago

The 18 min thing (or time to walk a Roman mile) is technically for a deaf dough. That is one that does not show signs of fermentation and one for which another dough that does was not made at the same time. Nowadays we treat all doughs as deaf, and we even take another stringency. According to Jewish law the 18 min is resting time after kneading, not time after flour meets water.

But that doesn’t mean that that tells us how to identify the signs for a dough that does show these signs.

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u/IbnEzra613 שומר תורה ומצוות 1d ago

That's an Ashkenazi stringency for the most part. Some Ashkenazi acharonim have said that if you knead a dough and then stop, the heat from the kneading might cause the dough to ferment instantaneously (I guess with the help of SuperYeast, pictured below).

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u/Complete-Proposal729 20h ago

Yes.

It bothers me that the 18 min thing is so widely known because most people misunderstand the actual rules.