‘Best before’ dates are tricky. No one wants to receive or buy something that’s close or past it’s ‘best before’ date, but it should be remembered that those dates mean best, before – not "eat by this date or the chocolate will suddenly decompose into grey powder".
If you keep your chocolate well, there’s a good chance it will still be in good condition another six months after the ‘best before’ – after all, it can’t be an exact science as the chocolate maker needs to build in some leeway.
We keep Seventypercent’s stock constantly in good chocolate conditions (14-20c, less than 50% humidity or thereabouts), so there’s a pretty good chance the chocolate will survive for longer. Certainly better than in a corner shop store next to the heater or by the fan exhaust of a modern till.
I’m testing this extensively by way of keeping my sample collection there, which includes bars going back three or four years. Although, it’s a bit like vintage wine – never tested. (Do you really want to open a bottle just to check it’s still ok?) There is however, some (open) Amedei Porcelana in the box from about 2003 – very different to what’s around now, but still surviving if slightly tamed by time. (This is in contrast to the wine fridge at home, which frustratingly has got clogged up with Callebaut, Lindt, Hershey, etc, etc from various travels – with an intent to review at some point, and almost nothing worth eating.)
Anyway, as it’s just past summer there’s always the inevitable handful of out of date bars to be had from stock while no one’s looking, so I’m currently working my way through some Michel Cluizel Concepcion bars that theoretically expired their last gasp on 25 August 2007. They’ve not lost any of their charm though, still holding plenty of that fruity top that seems to have been injected into Concepcion since it’s earlier, dry woody incarnations.
So I guess the moral is, don’t think you need to dispose of a good chocolate just because it’s past its date, assuming you’re the kind of person who might keep chocolate for long periods, that is. And even when past it’s very best, retempering can often revive a bar, or it will do just fine for baking.