put a cork in it! Screw It, put a cap. (or muzzle..?)

"I don't drink wine from a screw-top bottle." We've all heard someone say that. We've probably been the someone that said that. Probably because we associate cork sealed bottles with prestige and quality and screw-tops with inferior quality. But why though?! And does it even matter?

Short answer - no.
Long answer - maybe?

Ok. This is a huge topic and I'll try to make it as not nerdy as possible. Wish me luck. But once done, you will know practically everything about wine closures so stay with me!

First thing first. 
Does cork denote better quality wine? No. 
I think the reason for the link is that old world (European) wine still uses cork in the vast majority of its wine production. And because we tend to look to France, Italy etc. as the blueprint for wine quality, we instinctively think cork is tops. Not only is cork not necessarily tops, not all bottle corks are the same. Much of the time, it has little to do with quality and mostly to do with economics, sustainability and predictability.

Wine production is a painstaking and arduous process, from planting, to harvest to actual vinification, and the last thing a producer would want is to put their precious juice into a bottle only to be let down by the closure. Can you imagine?! At the same token, a producer also has to decide the price point and the aging ability of their wine. Does it make sense that one would use a closure that is good for 10yr aging yet the wine is an everyday wine meant to be drunk young within 2yr? Not really. 

Put a Cork in It !!!
Cork is a natural substance. It grows on specific trees in Portugal and Spain (a little in Italy and Algeria). 
It has been the traditional closure method for centuries because of its relatively tight seal and ability to allow oxygen contact and aging. Being a natural substance though, it is susceptible to variability, fragility and the dreaded cork taint inducing TCA; not to mention it isn't cheap.
Not all natural cork is the same though. We have the following types of corks:
Natural One Piece- This is the traditional cork which is made by cutting and punch shaping one piece of cork bark into the shape we all know and love. This only works if a standard size is required.
Colmated- A natural one piece of medium grade with the pores of the cork filled with cork powder allowing it to exit the bottle easier.
Agglomerated- Both standard and micro agglomerated corks are made by taking cork particles and basically gluing them together under pressure. This results in a strong cork that can be used for quick consumption wine and even age worthy wine. Also if  you need a larger closure, like for say a Champagne bottle, then these corks allow for size manipulation. The recent HELIX cork, developed by Owens Illinois LLC in conjunction with Amorim, is another example as to how the manipulation of agglomerated cork can lead to innovation in wine closures. This cork has grooves in it that align with grooves in the neck of the bottle to allow one to twist the cork out and also easily reseal it. 
Technical- These are agglomerated corks with natural cork affixed on either one or both sides of the cork
Synthetic - These are NOT corks but they are cork shaped, so... Made using polythene. It's a plastic sleeve with plastic foam within that can either be left exposed or covered completely.
*Bonus: The type of cork closure that is made with a straight shank of cork affixed on a  wider cap designed to be pulled out by hand is called a Bar Top cork. These are the kind found on Port and Sherry bottles.


Screw It !!!
While the trees are not endangered, obviously production of a natural substance has its constraints (see above), which is why Australians leaned to screw-tops. After a period of being relegated to being a secondary market for natural cork, Australian winemakers made the push to move to screw cap in order to have more stability and predictability in their access to closures. Taylors wine is credited for leading this charge and now, over 90% of Australian and New Zealand wine is under cap. Penfolds is the only brand that still remains a major cork user, but even they only cork a percentage of their bottles.
There was always conversation about the age-ability of the wine under cap, but this is changing as there are now caps that allow for controlled oxygen transfer.
They may not have the romaticism of the cork but at least they are easy access!
*Bonus: The official name for a screw top is STELVIN; developed by French company Le Bouchage Mecanique and first used in the 70's by surprise, surprise the Australians.

Put a Cap!
Aside from the two major closures above there are two other ways to seal wine bottles.
One is the glass Vinoseal which is a glass top, shaped like a conical cork that fits snuggly into the neck of the bottle. Personally, I think that it looks very chic, but let me tell you, opening them is not a walk in the park. A friend once showed me how, but trust me, it takes practice.
There is also the old crown bottle cap. You know the ones used on glass soda bottles or beer? Yes those. They pretty much offer the same benefits to the sparkling wine as they do soda or beer - keeping the fizz in!
 

AND an honourable mention to the Muzzle or as the French would say, Muselet. This is the wire cage that comes wrapped tightly around Champagne and other sparkling wine corks. It may not be top of mind when thinking of wine closures, but its job cannot be overlooked as it is what prevents corks from flying out of the bottles and spilling good bubbly (oh, yeah, and possibly injuring people). The round metal top bit of the cage is called the plaque and hobbyists that like to collect them are called Placomusophiles!

So next time you are getting your bottle of wine, don't agonize over the closure, trust me the producer already did that and picked the best one. From me, your wine friend, just enjoy the wine ;-)