The caves under Épernay are older than most visitors imagine. Long before anyone thought of sparkling wine, the chalk here had been quarried for building stone, and the old quarries, known as crayères, were later turned to storage. Merchants of the eighteenth and nineteenth centuries enlarged them into whole networks of galleries, and the cellars along the avenue still hold the wine at a steady, cool temperature of about ten degrees, whatever the weather above. In summer the contrast is dramatic, and visitors step out after a tour blinking in the heat, with their teeth chattering.
The thing to know is that the temperature drop is real: even on a warm day, a jacket is welcome below ground. Tours are usually guided and typically last about an hour, with a tasting at the end, and booking ahead is wise in high season. Some of the big houses run small trains through their galleries, a surprisingly cheerful way to see them. Nothing underground is suitable for bikes, of course, and you will need somewhere safe to park your machine and kit.
The town above, with its 27,000 people, is a plain working place with a long wine trade. There is fuel at the edge, a market hall in the centre, and a handful of decent places to eat. A Champagne lunch is a very particular pleasure, with fish, cheese and a glass of something dry, but it does not suit the afternoon ride. If you have to ride on, order a coffee, and take your time.
The UNESCO listing that includes the cellars recognises more than the wine. It recognises a whole way of life, from the growers' villages to the merchants' houses, and the infrastructure of cellars that made the trade possible. Standing in one of those cool galleries, with the rows of bottles stretching away into the dark, you understand how much patience the region has needed. It is a good place to slow down.