Several times I've used my 2-bag allowance to check one through upon departure, then wheel a carry-on out through customs on the connection in AMS, and fill it with beer. There's a great shop in Haarlem, Melger’s Wijn en Dranken, 30 minutes away by the #300 bus, which is a pleasant ride through countryside direct to the center of this very pleasant town.

I prefer that to the tumult of central Amsterdam, but there De Bierkoning by the Dam Square is another great shop.

If you don't have the 4 hours you should allow for that (though I've done it with 3), then the grocery store and the liquor store in the airport central terminal area do have some selection.

Then, it's upstairs to check the 2nd bag through to the final destination, and through security back to the departure gates. There have been times in the last couple years, though, when security (and sometimes passport) has been annoyingly slow.