Union Champagne’s new facility is built underground over two stories and holds 16,500 hectolitres of reserve wine.
It is fitted with a sophisticated cooling system to ensure the wine is maintained at an even temperature throughout the year.
The cellar features another room with 12 oak barrels, each containing 80 hectolitres of wine.
The oak comes from the Allier region and forests on the northern edge of the Champagne region.
Winemaker Yannick Collet said: “It is possible to distinguish through the different features of the blends, which forest supplied the timber.
“The proportion of wood-aged wine in the final blend is very small, with the intention that it will lend complexity and character to the wine, without revealing oaky elements.”
Laura Jewell MW, Tesco’s category product development manager, said: “Tesco has been working with Union Champagne to create Finest Premier Cru and Finest Grand Cru Vintage Champagne for over 20 years.
“Both wines are consistently awarded top accolades at international wine competitions, with Premier Cru winning a Gold Medal and Great Value Award at the International Wine Challenge and the International Wine & Spirit Competition Trophy for Champagne awarded by the Institut Oenologique de Champagne.
“These accolades are a reflection of the meticulous approach to quality taken by both Union Champagne and the Tesco wine team.
“The creation of the new cellar is an investment to support the quality and volume of the wines Union produce and I look forward to seeing further enhancement in the quality of the Finest champagnes.”