3,643. Taking Challah From Flour

Hilchos Bikkurim 7:13

One may make a ritually clean dough and not take challah from it. Rather, he may put all or some of it aside and take challah for other doughs from it until it has all become challah. This is the case for as long as the dough he put aside doesn’t degrade until it’s no longer fit for people to eat. This law applies even if the doughs are rendered ritually unclean. Once the dough is no longer fit for people to eat, challah can no longer be taken from it. All this is the case when there’s a doubt as to whether or not challah has already been taken from the doughs for which he is now taking challah. This is because a doubtful challah may be taken from ritually clean dough for ritually unclean dough at the outset, and they need not be in the same place.

Hilchos Bikkurim 8:1

Challah taken from flour (rather than from dough) isn’t challah at all. If one gives flour to a kohein, it’s like possessing stolen property and one must take challah from the dough that is made from the rest of the flour. If the flour erroneously taken as challah is an omer in volume (around a half-gallon) and a dough was made from it, challah must be taken from it the same as with doughs made from regular flour.