An Apple, a Rusty Truck & the Bump
in the bottom of your Wine Bottle
in the bottom of your Wine Bottle
By Ross Workman
It’s all about oxygen, really. When you cut an apple in half it will pretty quickly start to turn brown. Or, if you leave the old pick-up truck behind the barn long enough, it will rust. And if you leave half a bottle of wine on the kitchen counter for a few days it won’t taste very good. These are all the result of oxidation. Lots of stuff changes for the worse when exposed to oxygen long enough. Oxygen is the enemy of wine.
When people started making wine thousands of years ago they didn’t have a good way to keep it from oxidizing. So, unless it was fresh from the fermentation, the wine they drank was oxidized. But, since that was the way it always tasted, that was the accepted style until people figured out a way to store the wine keeping it from exposure to oxygen. Bowls evolved into pots and then into jugs that you could put a stopper in. Big clay containers called amphorae were used to transporting wine, the kind of things that are dragged up from the bottom of the Mediterranean now and then. None of these containers sealed very well.
Then the art of glass making was developed, and, in particular, glass blowing. By blowing molten glass into a mold, the artisan could make a bottle which could be stoppered with something, eventually a cork. But, when he disconnected his blow pipe from the new bottle, there was a little dab of glass left on the bottom, so it was tippy and wouldn’t stand up right. The fix was to push the pipe up into the bottom of the still molten bottle before disconnecting it. Then the troublesome dab would not be on the surface of the bottle that rested on the table. Instead it was up in the depression in the bottom of the bottle that we now call the “punt.”
Obviously we don’t use hand blown bottles anymore, so the punt isn’t really necessary. But, since it is there, some waiters will stick their thumb in it and use it to pour the wine in a way they think looks cool. And some wineries will order bottles with a deep punt to give the impression that the bottle is bigger. Bigger, heavier bottles somehow are thought to imply more valuable wine.
Actually, the bottle is not as critical as the closure. Corks do not provide a perfect air-tight seal. A few molecules of oxygen get past the cork and into the wine and do a tiny amount of oxidizing. That is part of the process by which the wine evolves as it ages in your cellar. Or, if you just age your wine in the back seat on the way home from the store, not much evolution occurs and the wine tastes fresher.
Enter the screw cap. It provides an air-tight seal, if properly installed. Hence, you don’t get the same kind of micro-oxygenated evolution as a cork provides. Now if somebody knew how many molecules of oxygen per month the cork allowed to pass, the screw cap engineers could probably match that with a screw cap. But I don’t think anybody has figured that out yet. So mostly we find screw caps on bottles of wine not meant for evolving in the bottle. Often they are on wines that the winemaker expressly does not want to change with time in the bottle.
Gradually, the wine-drinking public’s impression that screw caps were a sure sign of a crummy wine has died down as more good wines are coming into the house under screw caps. But the sommeliers haven’t yet figured out how to appear to be as useful and expert as they used to seem when pulling a cork. Unless some better technology comes along, we will be twisting off more bottle tops every year, though there will still be some corks around forever, probably.
But just imagine how the closure question would have developed if the screw cap had been invented before the cork. If we had been drinking out of screw capped bottles for a few centuries, we would be used to and favor fresher, less evolved wines. Then, say somebody invented the cork closure and tried to introduce it to replace screw caps. He’d have to persuade people that a little in-the-bottle oxidation was a good thing. And that corks were preferable, even though some irreducible minimum percentage of them wrecked the wine through the cork taint defect called TCA. And he would have created a need for all manner of tools to pull the corks out of the bottles instead of just twisting off the tops. Now that would have been a really hard innovation to sell!
So mind the oxygen and be thankful for the punt.