Eruvin 27B

לא נצרכה אלא שנתן לתוכן שמן.

R' Yitzḥak’s ruling that water and salt mixed together may be bought with second-tithe money was only necessary in a case where one added oil to them. But a mixture of water and salt alone may not be purchased with second-tithe money.

אמר ליה אביי: ותיפוק ליה משום שמן! לא צריכא, שנתן דמי מים ומלח בהבלעה.

Abaye said to Rav Yosef: If so, let him derive that the mixture may be bought with second-tithe money because of the oil alone. The Talmud refutes this argument: No, it was necessary for a case in which one paid the value of the water and salt by including it in the payment for the oil. Although ostensibly the money that he paid was for the oil, he added to the price of the oil in order to include payment for the water and salt that were mixed with it.

ובהבלעה מי שרי? אין ⁠— והתניא, בן בג בג אומר: ״בבקר״⁠ — מלמד שלוקחין בקר על גב עורו. ״ובצאן״⁠ — מלמד שלוקחין צאן על גב גיזתה. ״וביין״⁠ — מלמד שלוקחין יין על גב קנקנו. ״ובשכר״⁠ — מלמד שלוקחין תמד משהחמיץ.

The Talmud asks: But if something may not be bought with second-tithe money, is one permitted to buy it by including it in the payment for something which may be bought with second-tithe money? The Talmud answers: Yes, and so it was taught in the following baraita: Ben Bag Bag says in exposition of the verse: “And you should bestow that money on all that your heart desires, on oxen, on sheep, on wine, on strong drink, on whatever your soul requests” (Deuteronomy 14:26): “On oxen” teaches that one may buy an ox and include in its price payment for its hide. Although the hide cannot be eaten, it may be bought together with the ox, and it does not acquire the sanctity of the second tithe. “On sheep” teaches that one may buy a sheep and include in its price payment for its fleece, which is used for purposes other than eating. “On wine” teaches that one may buy wine and include in its price payment for its jug. “On strong drink” teaches that one is permitted to buy not only actual wine, but one may buy even mead, water in which grape seeds are soaked, once it has fermented and acquired the flavor of wine.