Sunday, August 9, 2009

Are synthetic corks better than natural cork for wine?

While my blog is often the grapes of wrath about some dumb company, politician or technology, today’s blog is about the fruit of the vine. Grapes are an amazing fruit and have been around as part of civilization from the beginning of recorded history. I live not too far from Napa and Sonoma two excellent wine making regions. My Mom and Sister were born in Stellenbosch an equally excellent place for wine making in South Africa.

The conversion of sugars and starches to ethyl alcohol via fermentation has been known to man and woman for at least five thousand years. What essentially has changed is the vessels in which the brew is fermented, the vessels in which the drinks are stored, and the stoppers that keep the alcohol from further oxidation and ruination. In the early days of wine making about 3,000 BC clay vessels held the wine and the stoppers were made of wood. Winemakers realized that wood was not an optimal stopper material and the bark of an oak tree in Spain and Portugal was found to be more pliable and an improved stopper. This is the origin of cork. During the medieval period folks kind of forgot their chemistry and forgot to use corks for closures and just drank their wine and beer as fast as they could manufacture the drinks. But a clever monk in France named Dom Perignon rediscovered the virtues of cork as a closure for his new discovered bubbly called Champagne. Dom was not Dumb even though the Afrikaans word for dumb is dom.

Cork and wine making have been synonymous for most of modern time since old Dom. Higher quality wines still use natural cork although other methods of preventing oxidation of the drink of Bacchus have now come to market. Old Bacchus was really Greek and not called Bacchus but Dionysus. As old Willy said “what is in a name” So why do folks fork out untold amounts for named vintage wines in old bottles that still have an intact cork? It must be that the cork did its job of preventing the egress of air into the bottle and therefore the breakdown of ethanol into less tasty and more toxic chemicals. Just last night I had some wine from Italy that came corked with a plastic cork from Supremecorq LLC I checked the company’s web site at and they claim the cork is made from a thermoplastic elastomer. I worked on thermoplastic elastomers for shoe soles back in 1980. Old Bacchus would have to resole his sandals if he found out that this is now going on. In truth the thermoplastic may perform just as well if not better as a closure for wine bottles. The cork tree may be a bit greener as the cork comes from the bark. By not felling the tree to produce the cork the tree remains alive and cork is therefore most probably greener than a block copolymer of styrene and butadiene, that I am guessing Supremecorq uses as their starting material. Cork is also less dense than the thermoplastic substitute so a case of wine will be a few grams lighter if corked with cork and not corq.

The beauty of a thermoplastic as apposed to a thermoset material is that it can be remelted and extruded over and over. Perhaps we can get bars to recycle the corqs, and Nike can make running shoes for high jumpers.