Pesachim 42B

דסמידא, בשר שמן ⁠— דצפירתא דלא אפתח, יין ישן ⁠— עתיק עתיקי.

is made from refined flour; fatty meat refers to meat from a goat that has not yet given birth; and aged wine refers to wine that has been aged significantly, for at least 3 years.

כל מילי דמעלי להאי ⁠— קשה להאי, ודקשה להאי ⁠— מעלי להאי, בר מזנגבילא רטיבא, ופילפלי אריכתא, ופת נקייה, ובשר שמן, ויין ישן ⁠— דמעלי לכולי גופיה.

The Talmud states a general principle: Any food or medical treatment that is effective in healing this sickness or this limb is deleterious for that one. And any food or treatment that is deleterious for this one is effective in healing that one, except for moist ginger, long peppers, and bread made of refined flour, and fatty meat, and aged wine, which are effective to heal all limbs of the body.

שכר המדי. דרמו ביה מי שערי.

The Talmud returns to its discussion of the details mentioned in the Mishnah. Why is Median beer prohibited during Passover? It is because the Medians place barley water into it.

וחומץ האדומי. דשדו ביה שערי.

And Edomite vinegar is prohibited because the Edomites place barley into it.

אמר רב נחמן (בר יצחק): בתחלה כשהיו מביאין נסכים מיהודה, לא היה יינם של יהודה מחמיץ, עד שנותנין לתוכן שעורין. והיו קורין אותו חומץ סתם.

Rav Naḥman bar Yitzḥak said: Initially, when the Temple stood and they would bring wine libations from Judea, the wine would be blessed and would be preserved without any additives. The wine of Judea would not turn to vinegar unless they placed barley into it to achieve this effect. And they would call this vinegar to which barley had been added ordinary vinegar, since wine would not become vinegar without this additive.