In article , Dave Henson
writes
A neighbour's grapevine is growing over my back fence. They don't use the
grapes and have said I can help myself. Having made wine from various things
in the past I thought I might try my hand at the 'real' thing but I am
unsure as to the suitability of these grapes. I don't know what variety they
are and also whether they are big enough.

About 15 lbs. of grapes are needed to give a gallon of unconcentrated
grape juice. Outdoor grapes are likely to be low in sugar, so you may
need to add extra sugar or grape concentrate according to how sweet or
dry you want the wine to finish. Any grapes will make wine, but the
result varies according to type and method of making.
--
Alan & Joan Gould - North Lincs.