Yes, I know that in conversational English people use "commodity" for anything that can be sold. But the fact that wine is sold is scarcely news to anyone here, so I assumed the the term was being used in a sense that it used in business/economicshttp://en.wikipedia.org/wiki/CommodityThe exact definition of the term commodity is specifically applied to goods . It is used to describe a class of goods for which there is demand, but which is supplied without qualitative differentiation across a market. A commodity has full or partial fungibility; that is, the market treats its instances as equivalent or nearly so with no regard to who produced the
If someone is not using that definition,and instead is using commodities as a synonym for "goods", then the statement that wine is unique because a bottle can be called wine at different price levels is just as confusing. Are there not watches, cars, shirts, suits, bicycles, stoves, tables, diamonds, olive oil, vinegars, TVs, and tens of thousands of other products that have enormous variance in price?
There might be some level on which wine is traded as a commodity on the very low end of the market (I thinking for bulk wines there might be contracts for X hectoliters of red wine min abv of 12%? I don't know). I do think there are commodity style contracts for grapes in CA (again, with some defining minimum standards for type and brix). All commodities assume some minimum standards (pork bellies can't be untrimmed or rotting!). And of course many commodity products have specialty versions that command higher prices (coffee is obvious, heirloom pigs obviously sell for more than tons of frozen bellies, fleur du sel, etc etc).