"Colonel Blip" > wrote in message
...
> I have read where it is possible to boil the grape must to make something
> akin to molasses and seal it

Boiling should pasteurize the juice and kill the microbes, but the character
of the fresh juice will be changed.

> (I suppose one could add something like
> potassium metabisulfite as well) and, since no yeast is added, could
prevent
> fermentation. Is this true?

Large quantities of potassium metabisulfite can inhibit fermentation, but
the quantities needed are so large the juice would not be useful for most
applications.

>snip..