Tosefta for Maasrot 5:6
הַמְתַמֵּד וְנָתַן מַיִם בַּמִּדָּה וּמָצָא כְדֵי מִדָּתוֹ, פָּטוּר. רַבִּי יְהוּדָה מְחַיֵּב. מָצָא יוֹתֵר עַל כְּדֵי מִדָּתוֹ, מוֹצִיא עָלָיו מִמָּקוֹם אַחֵר לְפִי חֶשְׁבּוֹן:
One who makes grape-skin wine, and he put water by measure, and he found [afterwards that the wine is] the same measure, he is exempt [from tithes]. Rabbi Yehudah requires [tithing]. If he found more than the measure, he must give [tithes] for it from another place, according to calculation.
Tosefta Demai
One who leaves behind [tithed] produce at the place of a Samaritan, behold, they are presumed to [retain their status] for tithes and for Shevi'it, and if they were untithed, he takes Terumah and tithes for them from another place (i.e., from other untithed produce, see Maasr. 5:6), or he designates the Terumah portion of the tithes from them. If they were from second tithe, he exchanges them for money, and he exchanges the money for the second tithe. If [the Samaritan] says to him, "I took it and I exchanged it for you for old [produce] in its place," or "[I exchanged it] for tithed [produce]," behold he should not be concerned about them (i.e., the produce) with respect to tithes or with respect to Shevi'it.
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