As far as I can tell, European connoisseurship in canned goods goes back about a hundred years. ... the European industry continued to rely on handwork and produced luxury goods for the well-off, who would age their canned sardines for several years like wine. Today, Rödel and Connetable, both more than 150 years old, are among the sardine makers that mark select cans with the fishing year and note that the contents “are already very good, but like grand cru wines, improve with age” for up to 10 years.
... Collins recounts an informal taste test conducted by a New York grocer who rounded up old cans from a number of warehouses, put on a luncheon in which he served their contents side by side with those from new cans, and asked his guests to choose which version they preferred. Among the test foods were fourteen-year-old pea soup and beef stew, and twelve-year-old corned beef and pigs’ feet. The guests preferred the old cans “by an overwhelming majority.” ...
I compared a new can of French sardines in olive oil with 2000 and 1997 millésimes. The brands were different, and so were the size and color of the fish and the quality of the olive oils. That said, the young sardines were firm and dry and mild; the older vintages were fragile to the point of falling apart, soft and rich in the mouth, and fishier in a good way. A 2007 (70th anniversary) can of Spam was also softer than the 2012 (75th), less bouncy and less immediately and stingingly salty, though the aromas were pretty much the same. Some Corti Brothers mincemeat aged for a year under a cap of suet was delicious, its spices and alcohols seamlessly integrated. A five-year-old tin of French goose foie gras: no complaints. Two vintages of Corti Brothers bergamot marmalade: the older noticeably darker in color and surprisingly reminiscent of Moroccan preserved lemons. And 3-year-old Cougar Gold—still moist and not as sharp as open-aged cheddars—was deeper in color and flavor than the yearling version, with a touch of caramel and the crunchy crystals that are the hallmark of hard aged Goudas.
--Harold McGee, Slate, on blowing past the best-by date