At this underwater winery in Croatia the glass bottles of wine are placed in terracotta amphoras, which apparantly create the perfect thermal conditions for ageing.
They first age the bottles in an aquatorium for three months, and later on, under the sea at a depth of 18 to 25 metres for one to two years... which you can also visit if you don a scuba tank and wet suit.
Bisson use the classic method to produce their sparkling wine with one obvious difference to most producers. The bottles are immersed onto the seabed and contained in metal cages at a depth of about 60 meters (environment at a constant temperature of 15 °) for about 26 months.
The resulting wine has "a straw-yellow color, a very thin and persistent perlage, a complex bouquet, an intense bouquet with clear hints of salty character, a frank and dry taste, long, intriguing and rich in minerality."