Chagigah 25 - Loopholes for the ignorant
We mentioned the five levels of holiness, one stricter than the other . However, we also mentioned that for the sake of the ignorant populace this is sometimes lifted .
For example, when an ignorant farmer brings oil or wine for his sacrifices, they are accepted, even though the vessels in which he brings them are most likely ritually impure. The law is lifted for the following reason: if the ignorant were excluded, they might build their own Temple. There was also a hope that they will be influence by the Temple's holiness for the good. This, however, is a loophole, and to avail of it, the consecration of the wine or oil must occur before the pressing, since this leads the farmer to purify his vessels first.
By contrast, there is no such danger in not accepting a priestly portion (terumah) from them - the ignorant will give it instead to another Kohen, his friend, who is anyway just as ignorant of the law of purity as the giver. Thus, the laws of terumah are stricter here. And yet, this same terumah may be accepted from the ignorant at the general time of wine pressing. This is because the knowledgeable people usually supervise the purification of all vessels for harvesting and pressing, and the priests can rely on that. The Sages also did not want the knowledgeable priest to be left completely without the priestly portion.
Art: The fine wine by French School