The ground in Chablis is full of oysters.

Very old ones.

Bend down in the right vineyard and you can find Exogyra virgula, a tiny fossil oyster embedded in the pale limestone and marl beneath the vines.

Around 150 million years ago, this was sea.

The sea left. The oysters stayed. Chablis eventually arrived.

This is Kimmeridgian geology: layers formed during the Late Jurassic and famously associated with the slopes around Chablis. The name comes from Kimmeridge, on the Dorset coast, where rocks of the same geological age appear at the surface.

And then wine does what wine does best.

It starts an argument.

Growers have long associated these soils with the particular character of Chablis. Drinkers reach for words such as chalky, saline, flinty, and the unavoidable mineral.

Science is less romantic.

There is no simple mechanism by which a fossil oyster travels through a vine and reappears as something you can taste in your glass. “Minerality” itself has no universally agreed sensory definition.

Which leaves us with one of wine’s better disagreements: place clearly matters; explaining exactly how we taste it is considerably more difficult.

We are not going to settle that in an Instagram caption.

But the vines are growing through the remains of a Jurassic seabed.

Which does make “a sense of place” sound rather less metaphorical.