Dear Rabbi Kornfeld,
a) I unfortunately haven't worked Mishnayot for Demai, Terumot, Ma'aserot, and
Ma'aser Sheni into my studies yet, but I was a little confused by the
discussion of Demai for the Background on the Daily Daf for Shabbos 23a. The
second sentence says "Ma'aer Rishon, Terumas Ma'aser, and Ma'aser Sheni must
be separated from [Demai]", while the third sentence says "Terumah Gedolah ...
and Ma'aser Sheni ... are presumed to have been separated," thus confusing the
issue with regard to Ma'aser Sheni.
b) Also, to further confuse me, the glossary of the Soncino Talmud edition that
I'm using indicates that for Demai, it is Terumah Gedolah and Terumas Ma'aser
that need to be separated.
- Charles Stein
a) Thank you very much for pointing out our error! And we apologize for the confusion. Here is our corrected text of the Background:
17) [line 39] DEMAI
(a) Produce bought from an Am ha'Aretz (an unlearned Jew who is lax in his Torah-observance - see Berachos 47b) is referred to as Demai ("Da Mai?" = "what is this?").
(b) Terumas Ma'aser, and Ma'aser Sheni must be separated from this produce since a minority of Amei ha'Aretz cannot be trusted to have separated them before selling it. Terumah Gedolah, however, (because of its stringency) is presumed to have been separated. Ma'aser Rishon and Ma'aser Ani are separated from the produce, but eaten by the owner (in keeping with the principle "ha'Motzi Mechavero Alav ha'Re'ayah").
b) Soncino is mistaken, for only Terumas Ma'aser and Ma'aser Sheni need to be separated from Demai.