Quercus suber, the cork tree (oak), grows best between 330 and 1000 feet, with 15-30 inches of rain annually, and in a climate which never falls below 23 F. As a species of oak tree, it is relatively young. Portugal dominates the cork industry, though Algeria, Morocco, and Tunisia together have similar acreage to Portugal, about 1.6 million acres. I didn't realize the cork industry actually started in Spain but was interrupted by the Spanish Civil War, and while it still produces corks, most are now shipped to Portugal to support the industry there. France and Italy produce corks too, just not to the scale the Portuguese do.
Winemakers with small production spend a great deal of time thinking about the package your wine ends up in. This ranges from the shape, color, and thickness of the wine bottle, the label, and of course, the type of closure for the bottle. Stelvin closures (screw caps) are common, and when cork is used, there are many considerations. The cork supplier will have different grades of cork available. Those with the least marks showing along the sides of the cork are rated highest, and are the most expensive. Cork length varies also, with the longest (55-60mm) being about 5 times more expensive than the cheapest corks. You might have opened a bottle from Bordeaux or Barbaresco and had an unusually long cork (compared to most New World wines), since longer corks have a longer life as a closure.
I had an opportunity to visit a cork supplier recently to do a sensory analysis of the corks we'll be using this year for bottling. To prepare for the sensory analysis, the cork supplier takes random corks from specific batches, soaks them in a neutral alcohol for up to 36 hours, then remove the corks and pour the alcohol into wine glass which are then covered with slightly concave glass covers. We had about 45 glasses to sniff through, all numbered individually, and a sheet of paper with corresponding numbers to make notes on. These numbers also correspond to the batches.
Some of the notes we made for individual glasses (hence, corks) were, 'peppery(2x), off-odor (musty), bitter, soapy, slight chlorine odor'. Of the 45 samples, these were the 6 standouts. 'Peppery' might be fine, but 'musty', 'chlorine', and 'bitter' are warning flags. In the end, Kevin (see previous post for Kevin Kelley) chose the cleanest lots and those are the batches we'll end up with for bottling!
All wineries take care in their packaging, but a large producer (Yellowtail comes to mind) will assume that little attention beyond brand recognition is paid to the whole package. This is as it should be with that size production. A small producer might assume more consumer scrutiny, and will take care to coordinate the elements of their label (color, say) with the capsule (the foil over the cork). For a small producer, each unit sold has to be everything the buyer expects before the bottle is even opened.