Britain's connoisseurs have long entrusted their best tipple to private firms for safe keeping.
The idea only crossed the Channel to France, which produces much of the great wine that interests collectors, when a well-heeled Asian clientele started driving up prices.
One of the pioneers in the business, London wine merchants FINE+RARE, started renting space to customers in 1994 to keep good bottles out of harm's way -- from thieves and other enemies like fickle temperature, light and vibration.
France took notice when wine prices began soaring -- first with Bordeaux varieties around 2010 before Chinese buyers also turned to bottles from Burgundy, which are more rare, according to Angelique de Lencquesaing, founder of the online auction site iDealwine.
Also Read
The "WineDexBordeaux," an index established on her Internet site, has climbed by more than 103 percent since 2007, while the "WineDexBourgogne" (Burgundy) has gone up by 113 percent.
"The prices of some great vintages are so very high that storage is like an insurance that doesn't cost very much," said Andrew Amiach, who runs the Montquartiers wine cellars, not far from Paris.
In such cases, a collective cellar is used, but tight security measures still apply. Of 10 employees in the Montquartiers company, only two have a key.
"To avoid the slightest temptation, corkscrews are banned," Amiach said, smiling.
Today, the Montquartiers cellars stock 100,000 bottles owned by some 300 clients, including wines fit for well-off epicures such as a 1900 Sauternes and a pallet of Romanee-Conti bottles worth a total 100,000 euros.
Businessman Philippe Gangneux founded La Cave Lyon -- modelled on a seasoned storage business in the French capital called La Cave Paris -- in a former factory three years ago, now safeguarding wines some customers don't dare keep at home.
Like the guardian of a temple, Gangneux knows the stories behind labels, and bottles are synonymous with their owners.
"Over here, you have a client who lives in India. Twenty per cent of my clients live abroad," he added.