3,648. Challah and Ritual Impurity

Hilchos Bikkurim 8:10

If there’s a doubt as to the ritual cleanliness of dough before it’s rolled, one must prepare the dough in a state of uncleanliness. This is because we are allowed to render secular produce unclean in Israel. The challah from this dough is to be burned. If the doubt arises after the dough has been rolled, and it’s a type of ritual cleanliness which, if was definitely unclean, would convey impurity at the Biblical level, then the dough must be prepared in ritual cleanliness. This is because when it comes to a situation in which impurity would be conveyed to secular produce in a case of certainty, the Sages ruled that, in a case of doubt, a dough that is already obligated in challah may not be rendered unclean intentionally. Rather, the challah taken is “suspended,” i.e., it is neither eaten nor burned.

Hilchos Bikkurim 8:11

Optimally, one should not prepare dough in a state of ritual uncleanliness. Rather, he should try to purify himself and his utensils in order to take challah in ritual purity. If he is more than four mil (about 2.5 miles) from water (for purification, e.g., a mikvah), he may prepare the dough in uncleanliness and take ritually unclean challah.