Everything you need to know about screw caps...

Screw caps and cork

The screw cap used on a bottle of wine differs from that used on soft drink bottles and other food grade items. It has a tin liner (there are others, but in Australia mostly tin is used) that has been developed specifically for protecting fine wine while maturing in the bottle. The tin liner is the only part that is in contact with the wine, and is designed to stay stable and flavour neutral for the life of the closure. There are many examples of Riesling being bottled in the late 1970 and early 1980 period and these closures are just as good as the day they were sealed. The wine is also fresh and untouched in a manner that is very satisfying to a winemaker.

Cork taint and random oxidation – is it really a problem?

Corks have serviced the wine industry for many centuries. However, most credible research has the level of cork taint (mouldy character) at about 5% while random oxidation (flat and brown wine) is difficult to pin point due to its insidious nature. A good cork is no doubt similar to a screw cap, but how do you know if you have a good cork? Due to its very nature of being a natural product, there is no definitive way of knowing its exact sealing capability. If of a car maker had one of its wheels fall of 5% of its cars who would buy that car? I rest my case. Additionally, recent research has shown that red wines will age the same under a screw cap as a cork with the benefit of knowing that the wine will be 100% safe from cork taint and random oxidation. Quite frankly it’s a no brainer, without mentioning the convenience and ease a screw cap allows the consumer who just wants to pour a glass and relax.

What if they fix the cork problem?

It is unlikely we will use corks in our wines because we believe that white wines hold their aromatic aromas better under screw cap and you can actually taste the wine as being fresher! We also believe red wines age more gracefully in screw cap, developing lovely tannin and fruit complexity. There are now many wine producers who have switched to screw caps for reds and the evidence is now quite clear that both red and white wines age very well when sealed with a screw cap.

Will reds 'breathe' properly?

Yes and No. Reds don’t need oxygen to mature so the question is not really that important. Young red wines sealed with a screw cap will benefit if opened and decanted for a few hours but this is only to allow the wine to express itself. Think of being crammed up for a short period and then allowed to stretch. The myth of red wine needing to breathe in bottle is just that, a myth. And if a good cork is similar to a screw cap it stands to reason that some corks do not allow a red wine not breathe either. A recent study found that red wine will continue to mature irrespective of oxygen ingress through a closure, and that oxygen ingress simply amplifies the rate of maturation. To put it simply, the more air, the faster your wine matures.

What will happen to cork?

Cork sales and volume are still going up due to increased wine production around the world, however, long term it is difficult to say that cork usage will not decline. The cork manufactures are improving the quality of corks and innovative research is helping the industry rid itself of a large percentage of its problems. In the future, many other producers may wish to stay with corks or return to them, but the DogRock team believes that screw cap closures will be used by quality conscious producers of super premium wines, in the immediate future anyway.