[Avodah] Concord wine for 4 kosos

[Moshe Yehuda Gluck]

R' MB:
*A hybrid of concord grapes and old-world grapes is seedless, ie a mule.
*This
*is why the former is called Vitis labrusca, and the latter, Vitis vinifera.
*I
*believe that this inability to crossbreed to produce fertile offspring is
*halachically sufficient to consider them two species.
*
*So, how do we know that concord wine is yayin for 4 kosos? Why isn't it
*chamar
*medina? Perhaps its use, and making a hagafen/hagefen on it is a practice
*entrenched before the botony was better known?

See Pesachim 35a, "תנא כוסמין מין חיטין שיבולת שועל ושיפון מין שעורים" - it
appears that whatever taxonomy was used by Chazal was sufficiently broad to
allow these to be considered subspecies of some sort of wheat and barley.
Presumably, hybrid/seedless grapes are still considered grapes, and their
fermented juice, wine.

KT,
MYG