Every tin in the aisle is a copy of the sardine. The anchovy in oil, the tuna in brine, the mackerel in tomato, the mussels in escabeche: the whole shelf descends from a business first worked out, at scale, on this one small silver fish. It is the oldest thing in the modern aisle and the reason the aisle exists at all.

Sardina pilchardus is a small fish that moves up the Atlantic in vast schools, from Morocco to the Bay of Biscay and through the western Mediterranean, and for centuries it came ashore in such numbers, and so cheaply, that it fed entire coasts. It is also oily, which turned out to be the crucial thing, because oil is what survives a can: a lean white fish turns to cotton wool under heat and time, while a fat one holds together and can even improve.

The trade began in Nantes, in 1824. A confectioner named Pierre-Joseph Colin, working from the sealing method Nicolas Appert had proved a few years earlier, packed sardines in oil in a tin and found they kept beautifully. Within a decade his factory was turning out tens of thousands of tins a year, the Breton coast filled up with canneries doing the same, and the shape of the whole trade, the presses, the ports, the flat little key-opened tin, formed around that first sardine line.

The fish fattens through the summer, feeding in the cold, plankton-rich Atlantic, and the good canneries pack it at that peak, in the few weeks it carries the most oil. So a tin is a particular summer caught and kept, the fattest weeks of the year sealed under a lid and set on the shelf to wait for you.

The fish that taught the world to can is still there at the cheap end of the aisle, still the best value in it, and a good tin, warmed just enough to loosen the oil and laid on bread or a boiled potato, is as fine as anything on the shelf it started.