[Avodah] Concord wine for 4 kosos

[Micha Berger]

I came up with the following originally as a joke, for "The Chumrah of the
Month Club". However, I now repeated it so many times, I can't see the flaw in
the reasoning. Please talk me down...

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?

Tir'u baTov!
-mi

-- 
Micha Berger             Spirituality is like a bird: if you tighten
micha at aishdas.org        your grip on it, it chokes; slacken your grip,
http://www.aishdas.org   and it flies away.
Fax: (270) 514-1507                            - Rav Yisrael Salanter