> > I just purchased a cheap bottle of Australian Shiraz and I've noticed a
> > slight soapy taste... Is this considered a bad trait in a wine?... >
> It may just be the way my taste buds work, and it may be described
> differently by others, but I've found what I describe as a "soapy"
> taste/sensation in a number of cabs.
I wonder if you're not tasting "salty" and confusing it with "soapy"?
It's fairly common practice to do a final adjustment to the free sulfur dioxide in wines just before bottling, using potassium metabisulfite. The amount is not much, but tends to be more in a high pH wine (most California Cabs are fairly high in pH) - and the potassium doesn't have anywhere to go, as red wines are not usually cold stabilized (which would precipitate excess potassium as bitartrate).
Potassium has a different flavor from sodium; I suppose you could characterize it as "soapy".
Tom S