Have you ever wondered why two bottles of wine, supposed to be identical in almost every way, sometimes differ in taste and aroma? In other words: Why would two bottles stored under identical conditions taste different?

A few years ago, I was privileged to select and receive a couple of cases of wine that were stored for more than three decades in a decrepit garage. Storage conditions were, to say the least, not ideal. Nevertheless, I’ve found a few gems within this evolutionary challenged lot of wine. Like the 1980 Vergenoegd Cabernet Sauvignon that I opened last night. It was obviously far past its prime, but still shouted Cabernet Sauvignon with a creaky voice. This made me ponder upon the question right at the beginning of this blog.

Bottle variation becomes much more accentuated with time, which is why modern wineries crave uniformity when it comes to bottling of their future old-timers. Gone are the days of barrel by barrel bottling (an exception is Domaine de la Romanee Conti), uneven fill levels and bottling at different temperatures, times and venues. Before the wine trade exploded in Hermitage, wine was sold and bottled barrel by barrel as orders came in. The impact of bottling date barrel variation in this case was huge.

The type of closure (cork or screw cap) plays a critical role in bottle variation. It is even suggested that the cork is the most important factor in bottle variation and I am inclined to agree. A high quality cork will ensure a more uniform wine and will reduce the incidence of embarrassment following the opening of an expensive wine and having someone declare with a snooty voice: “I believe this wine is corked.” No two corks are similar and there can be a remarkable difference between two seemingly similar corks in terms of oxygen transfer into wine. If you want to know more about the effect of oxygen on wine, feel free to read my previous blog about the effect of ageing and micro-oxygenation on wine. By the way, you can treat a wine affected with cork taint at home. Simply line a bowl with polyethylene plastic food wrapping and pour the affected wine into the bowl. The taint will disappear or be much reduced after only a few minutes.  TCA (the molecule usually responsible for cork taint) has a very high affinity for the polyethylene molecule and will adhere to the plastic sheet. If you were wondering, I did not see this trick on MacGyver.

If you still do not believe that evaporating wine (from a bottle) is replaced by air, consider that you’ll very seldom see a cork that is sucked into a bottle. This is because the wine that escapes the bottle is replaced by air. Now that we’ve established that air does indeed find its way into a bottle of wine and that this is very dependent on cork variation, I will conclude this blog. You can read more about the other factors critical to bottle variation in Part 2 of this blog.

Until then, why not open a golden oldie and reminisce about the good old days. A good bottle of old wine might be hard to find, but the reward is totally worth the anguish as you pull, inspect and smell the ancient cork…

Bernard Mocke is a technical consultant for Oenobrands.