Now, this is not exactly a widespread practice. In fact, only one US winery—Mira Winery in Napa Valley—has embarked on such a project to our knowledge. Still, the TTB is concerned about more than just crabs getting into your Merlot.
“Overpressure on bottle seals increases the likelihood of seepage of sea or ocean water into the product,” the TTB writes in its advisory. “As a result, variation in overpressure during tidal flows and storms would allow the bottles to ‘breathe,’ or exchange contents of the bottle with the sea or ocean, as the bottle tries to equilibrate its internal pressure to the external sea pressure, and chemical and biological contaminants in ocean water may contaminate the wine.”
Read the rest on Munchies.