Maaser Sheni, Chapter Four, Mishnah Eight
It would have been common practice to set aside a coin and then use it progressively as money for maaser sheni produce. In our mishnah a person sets aside an issar, which is worth 1/24 of a dinar, and then uses that issar as redemption money for a future amount of maaser sheni produce that he will eat. The question that arises is: what happens if the value of the issar changes?
1) One who sets aside an issar [for the redemption of maaser sheni] and on its account he ate [the value of] half [an issar of maaser sheni] and then went to another place where [the issar] was worth a pondion, he may eat of [maaser sheni the value of] another issar.
2) One who sets aside a pundion [for the redemption of maaser sheni] and on its account he ate [the value of] half [a pundion of maaser sheni] and then went to another place where [the pundion] was worth an issar, he may eat [maaser sheni the value of] another half [an issar].
3) One who sets aside an issar of maaser sheni [money] he should eat on its account eleven parts of the value of an issar, or [he should eat an additional] one hundredth of an issar.
a) Bet Shammai say: in both cases one tenth part [of an issar].
b) But Bet Hillels says: in the case of certain [maaser sheni] an eleventh part, in the case of demai a tenth part.
Section one: A person set aside an issar to use as redemption money for maaser sheni produce that he will eat in the future. Then he ate half of an issars worth of maaser sheni, meaning that half the issar was still not maaser sheni money. Afterwards he took his issar and went to a place where the issar was worth a pundion, which is two issars. The issar doubled in value, so the half that was left unredeemed was now worth a full issar in the old terms. Therefore, he can redeem another issars worth of maaser sheni produce before the coin is fully maaser sheni.
Section two: This is the opposite case. He set aside a pundion, which was worth two issars, and he ate half of the value. Then he took the coin and went to another place where the pundion was worth half as much, only an issar. He can now only redeem another half of an issars worth of maaser sheni produce, because the half pundion that was not yet maaser sheni is now only worth half of an issar. The rule seems quite straightforwardthe value of the coin is determined by its value in the place where he redeems the produce.
Section three: The following is Albecks explanation of this section. We should note that its language is very difficult and there are many different interpretations.
The mishnah refers to a person who is in Jerusalem and eating produce as maaser sheni based on the coin that he has at home. As he eats the produce the coin will be redeemed and will revert to being hullin. The custom in their time was to buy food at 1/10 of an issar or 1/100 of an issar. Since the price of an issar would rise and fall as we saw in the previous section, he would need to eat 11 parts of an issar and not ten parts, and only then would the issar become hullin. Alternatively, if people are buying produce at 1/100 increments, then he needs to eat 101 parts of the produce before the issar is totally redeemed. This is a stringencyhe needs to buy more produce than the coin may actually be worth.
Bet Shammai says that in all cases, both cases of certain maaser sheni and demai, doubtful maaser sheni, one needs to eat only 10 parts of the issar, meaning a complete issar. He does not need to eat the extra 11th part, in any case.
Bet Hillel is slightly stricter. When the coin was used to redeem produce that was certain maaser sheni, he needs to eat the eleventh part. But when the produce was used to redeem demai, produce that already may have been tithed, all he needs to eat is the first ten parts, the actual value. We dont have to be concerned lest the issar increased in value, when the produce may not have needed to be tithed in the first place.