Earlier this year I was on the island of Vulcano, one of a flotilla of small land masses that poke up from the Tyrrhenian Sea off the northeast coast of Sicily. It’s the place that gave European languages the word volcano, and one of four of Italy’s active, above-ground volcanic centers is located here. The photo above is a view from its cone.
I didn’t climb its slopes, but I can tell you that the moment I set foot on the island I smelled the sulfur in the air. It isn’t the pleasantest sensation, but one of the reasons the up and coming Roman Republic was willing to go to war over control of the islands was because they could collect sulfur easily here. The element was a valuable one in the ancient world, in regular use as a general purpose fumigant and a key ingredient in medical balms and ointments.
It was known from early days that wine held in a barrel fumigated with a sulfur match would keep longer. But it wasn’t until the 19th century that we drew the curtain back on the yellow stuff’s special powers when Pasteur demonstrated its talent for killing the newly discovered creatures known as bacteria.
Today, sulfur is widely employed in winemaking in both in the vineyard and in the cellar. It’s a cheap and effective treatment against two scourges of viticulture, the powdery and downy mildews (organic rules permit its use). In the cellar, it has a host of applications, all aimed at either suppressing unwanted biological activity or as a prophylactic against oxidation. Grapes may be dusted with it at harvest. Finished wine may get a first dose (in the form of potassium metabisulfate – a compound that releases sulfur dioxide when dissolved in an aqueous, acid liquid) once it is safely tucked away in barrel and a second when it’s bottled.
SO2 is especially valued in the making of white wines that depend on very limpid hues and bright fruit for their market appeal, since it retards the processes that would otherwise result in browning and a diminution of fresh fruit flavors.
It all sounds peachy until you realize that for all its wonder-working properties, sulfur has a dark – some might even say diabolical — side. [Read more…]