I read somewhere that Stella (at least draught) sold stateside is brewed under license in Wales. Must be that tasty mine slag infusion in the water.
Wouldn't be surprised - the Stella sold in England is made at the old Whitbread brewery in (I think) Luton - even the bottles/cans came from there (for a time at least). And the taste could indeed be a tip-off - as I noted earlier the bottled Stella sold in the USA has a crisper taste than the draught.
Demand for the stuff all across Europe is such that the original Horn Brewery in Leuven (Louvain) couldn't possibly keep up - in Croatia, for instance, the Stella sold there is brewed at the Ozujsko brewery on the west side of downtown Zagreb (Ozujsko is, like Stella, owned by InBev). And back in 2003 when I toured the Pilsner Urquell brewery I heard they were planning on opening a second brewery in Poland to handle their increasing demand, but I haven't seen anything further about that.
The bottled Stella sold in the USA, last time I looked, is still from Belgium...and whatever became of the people who'd take the P&O Stena Line ferries to Calais and fill up their cars with a job lot of cases of Stella? I don't hear much about that any more on my annual trips over to London - tax laws must have changed and rubbed out the price advantage, perhaps.