We go back again (061): Rabbi Abahu quoting Rabbi Shimon ben Lakish: If Maaser was separated from ears of grain [before it became obligated in Terumah separation], it becomes Tevel with regard to Terumas Maaser [the Levi is obligated to separate Terumah, although it is not yet at a stage which would ordinarily require Terumah].
Question: Why does it require Terumah at this stage?
Rava: Since it acquired the title of Maaser.
The following paragraphs are found very frequently in Shas.
Rabbi Shimon ben Lakish: If one separated Maaser from unprocessed grain, there is no obligation to separate Terumah. As it states: “You [Levi’im] shall separate from it Terumas Hashem a tenth of the Maaser”. Maaser is obligated in Terumas Maaaser but not in Terumah.
Rav Papa to Abayye: According to this the Levi shouldn’t be obligated in Terumah even if the grain is processed, as long as he took it before the owner separated Terumah?
Abayye: Because of people who ask questions like you, there’s another verse “From all the gifts [Maaser that you receive] you should separate Terumas Hashem”.
Challenge: Perhaps the first verse refers to processed grain and the second refers to unprocessed grain?
Resolution: The processed grain is already obligated in Terumah, so it only makes sense to apply the verse obligating Terumah to the case of processed grain.We learned there [Mishnayos Maasros]: One who is peeling barley [an unusual way of processing] can peel off one grain at a time and eat it [it is considered ‘casual eating’ which is not obligated in Terumos and Maasros], but if he peels to put in his hand [more than one at a time, it is considered processing and] he is obligated in Terumos and Maasros.
Rabbi Elazar: The same applies to Shabbos [threshing is a Melacha, but if he peels only one at a time, it is not considered a Melacha].