(MunchiesVice) - It’s already hot when I reach the small port of the Saint-Mandrier peninsula in the department of Var at 9 AM. With no sign of wind and waves barely 12 inches high, it is the perfect weather for tossing the region’s wine into the sea. Or at least it is according to Jérôme Vincent, the director of the Ecole Nationale des Scaphandriers (National School of Divers), who is waiting for me in front of his inflatable boat, ready to embark on the open ocean.

For someone like me who hails from the Southeast of France, Bandol is like holy water. I wouldn’t say it fuels my life, but during the summer when the clock strikes noon and the crickets are singing, it’s a local tradition to open up a bottle of fresh rosé. Hiding a cargo of the stuff in the Mediterranean Sea with a team of divers, on the other hand, is a first for me in oenology.

This initiative to study the aging process of regional wines was co-launched by the Association of Bandol Wines and the Oenothèque of Bandol Wines, in collaboration with the National School of Divers (ENS). “Divers are the only ones with the skills to carry out underwater work,” explains Vincent. In this particular case, a serious construction project is at hand: digging deep into the Mediterranean by building an aquatic cave, dropping the bottles in and covering them layer by layer with sediment.

To take on such underwater efforts, your average diver doesn’t fit the bill. Before the digging can begin, the divers have to find a quiet spot, “away from the pirates.” Apparently, around here, word travels fast, and even more so when what’s at stake is a veritable treasure trove of booze.

Fifteen different winemakers are participating in the operation, which includes the 2011 vintage red and the 2014 batch of white and rosé, totaling 240 bottles. For 18 months, half the hooch will remain 131 feet deep in 59- to 68-degree Fahrenheit water, while the other half—comprised of 120 identical bottles—will age the traditional way inside a cave.

A myriad of factors influence the aging of wine: here, the goal is to compare the effects of sea currents and temperature. Underwater, wine benefits from optimal conditions that are believed to improve its quality: namely, very faint variations of pressure and temperature in complete darkness and very little vibrations. “Bandol wine is known for holding up well during sea crossings and is even enhanced by the gentle rocking of the waves,” explains Guillaume Tari, president of AOC Bandol. In the microclimate of Bandol, valleys of vineyards go down the coast. The sea regulates the maturity of mourvèdre, the region’s staple grape variety. “Paradoxically on the Mediterranean, the tidal coefficient is very low, but mourvèdre is very sensitive to lunar cycles,” he adds.