How Much to Drink for Kiddush?

The Rabbis taught: One may not recite kiddush over beer.

From the name of Rabbi Elazar, son of Rabbi Shimon, they said: "One may recite kiddush."

By tasting any amount of wine.

Rabbi Yosei, son of Yehuda, says: "A cheekful."

Rav Huna said: "Rav said -and Rav Giddel from Neresh likewise teaches: 'One who recites kiddush and tastes a cheekful has fulfilled his obligation, and if not, he has not fulfilled his obligation.'"

Rava said: "The elders of Pumbedita stated these two matters: One was this mentioned above with regard to lifting the barrel; and the other was: With regard to one who recites kiddush - if he tasted a mouthful, he fulfilled his obligation; however, if he did not taste a mouthful, he did not fulfill his obligation."

How much to drink on Yom Kippur to be liable?

Beit Shammai say: "A quarter-log,"

and Beit Hillel say: "Two cheeks full." Rabbi Yehuda says from the name of Rabbi Eliezer: "Like two cheeks full." Rabbi Yehuda ben Beteira says: "In order to swallow."

Rav Yehudah said: "Shmuel said: 'Not actually cheeksful, rather, all who pushes to one side, and it appears as though his cheeks were full.'"

Similarly, "a mouthful" is required, as stated in Chapter Halon: "If one who sanctifies (performs Kiddush) tastes a mouthful, he has fulfilled his obligation; if not, he has not fulfilled it" (Eruvin 79b).

Rabbeinu Tam explains that there too, a mouthful is required, as we need "settling of the mind" (Yituv Da'ata). For if it meant an actual full mouthful, then it would be more than a quarter-log (Revi'it), as is proven here. Since it establishes the measure as a mouthful, the question arises: If so, this would be a leniency of Beit Shammai. However, initially, when it said "a mouthful," it was not problematic, because if that were the case, why would such a large amount be necessary? After all, it is stated in Chapter Arvei Pesachim (Pesachim 108b) that the measure of the four cups is a Revi'it, and the cup for Kiddush is one of them.

If so, how can one fulfill their obligation for Kiddush since a mouthful is required? Moreover, if one were to think that a mouthful is more than necessary for settling the mind, then why did they establish a separate measure for each individual? If it were simply "a mouthful," it would be reasonable, as explained further: The Rabbis determined that this is the amount sufficient to settle the mind of most people, while for someone like Og, King of Bashan, it would be insufficient.