Rabbi Aryeh Lebowitz

So, says the Rosh, the Shemira is only required from the time that you make it into wheat.

Shulchan Aruch says that at the very least you should try for that, meaning, But Shulchan Aruch and Tophim Gimel says, minimally try to attempt to get matzos that are baked under at least that level of supervision, that from the time that they were ground up into flour, that there was a Shemira.

Most machine matzos, even if it doesn't say Shemira,

are made under that level of supervision, that from the time it was ground up into wheat, that it was protected very carefully.

Now, it may not be that it was done Lashma, but at least it was protected very carefully from that point on.

The She'ulta Sravachaygon in Parshat Tzav, She'ulta Ayin Vav, says that watching isn't even necessary until the flour comes into contact with water.

It's the most making sheep.

that once the flour comes into contact with water, that's when you really need to be on guard, and that's where the chi of Shemira kicks in.

Again, however you understand the chi of Shemira, whether it be according to the Rambam, just protecting it, make sure it doesn't become a chametz, or according to Rashi, that's where you start saying that you're doing it l'shema.

That's what we refer to as Shemira Mishas Lisha.

If you ever hear that phrase, Shemira Mishas Lisha, Shemira from the time of the kneading.

It's not literally from the time of the kneading.

It should be, because as soon as the flour comes into contact with the water, the kneading needs to be done

right away.

In reality, our flour very often is washed prior to packaging, and that comes obviously before the kneading.

Now, any such washing would turn the flour into real chametz.

That's why flour, when people say, I don't sell chametz gum or mustamah, they shouldn't sell flour either, raw flour either, because pre-washed flour is probably real bonafide

chametz, already.

That's the way they use special flour that's not pre-washed flour in the matzah bakery.

So even though the Mechaber says that a person could buy regular flour from the market, Mechaber postings that if you don't have matzah on Pesach,