The wonderful world of closures may not, at first glance, appear all that exciting. However, it is a topic that garners a lot of questions and plays a pretty important role in the wine we drink. In the most basic sense, the closure keeps the wine safely in the bottle and prevents oxidation, so we can enjoy it.
However, for a producer their choice of bottle closure can be critical. If this seems a bit hyperbolic, put yourself in their shoes for just a moment. Imagine you have only one stab each year at making the best wine possible. Consider that your livelihood and reputation rest on the contents of that bottle. Then think about the time spent in the vineyards, tending the vines and the myriad of decisions you have made throughout the growing season. Think about the sleepless nights and early mornings you have faced when bad weather threatens to damage or reduce your yield. All of this is before you have added up the investments made in the winery, and the time (often away from family) spent travelling to promote your wine.
As such, the wonderful world of closures is definitely of importance. So we have pulled together a list of those you may come across:
Natural cork
We are all familiar with this classic closure. It has provided a pretty consistent solution for keeping wine in bottles since the 1600s. Many great wines have aged happily under cork and for numerous consumers and producers it is still a favoured option. However, it is a natural product and with that comes imperfections. The main problem is 2,4,6-Trichloroanisole (thankfully referred to as TCA). This is a unpleasant compound that smells and tastes a lot like wet wool, or musty damp cardboard. Not great characteristics for a glass of wine! But, on the plus side, corks are biodegradable, recyclable and cork forest encourage indigenous wildlife.
Technical Cork
This is a cork made from natural cork particles. In many cases, they are treated to ensure that TCA and other faults are eliminated. The most commonly seen technical cork is DIAM. Like natural cork, they can be recycled, but vegans should check on the glues used in their production. Indeed, some claim that the glues can impact negatively the aroma of the wine.
Screw Caps
Screw caps are commonly seen. Also referred to as Stelvin (the brand name). Screw caps are widely used and excepted in most markets. They are convenient and easy to open, and there is no risk of TCA. The use of breathable cap liners allows producers to consider the drinking windows for their wines and they are tamper-proof. On the downside, the stinky aromas associated with reduction are more common with wines bottled under screw cap. Though the are by no means the only closure where this occurs. Furthermore, issues with denting and compromised seals can lead to oxidation.
Synthetic Corks
Originally rather ugly, plastic corks, synthetic closures have come a long way. Our favourite is the Normacorc's planet-based ‘green’ closure. This is made from sugarcane polymers, is recyclable and is the first closure with zero carbon footprint. It also looks very different to the synthetic corks of old. The traditional polyethylene closures, are still about and these can scalp the fruit from wines. Some argue that they are only really appropriate for wines being drunk in the first year after vintage.
Crown cap closures
There are other types of closure, including Vinolok (a glass stopper with plastic o-ring to ensure the seal). Zork closures (used for sparkling and still wines). These are made from plastic, but they are recyclable. Crown caps are also used, you will come across these on sparkling wines, like Pet-Nat.
In conclusion, though this is often viewed as a dry and technical topic and each closure has its pros and cons, you can rest assured that the person who made the wine you are enjoying, has tried to ensure that the very best option for their wine was selected.