Cork vs screw cap…what’s the difference, and what’s the future?

Layers of cork bark, Portugal 2018

You’re standing in the wine aisle at your local shop, holding two different bottles of Pinot Noir. You know by now that you enjoy an Australian style and the descriptions on both bottles are intriguing, but one is a screw cap and one is natural cork. Your gut tells you to go with the corked bottle because that’s the way it’s always been done, but is that really correct? What does the wine bottle closure actually mean as far as quality, sustainability, and taste?

There are many ways to seal a bottle of wine, with new technology emerging every year. Here we discuss a few of the most common closures to help you make more informed decisions, and maybe even impress your friends at the next dinner party.

  1. Natural cork has been around for centuries and is used for around 80% of wine bottles today. It comes from the bark of a cork tree and is flexible enough to be easily pressed into the bottle stem before it expands to create the seal. A small amount of air comes in through the cork, which can be good for aging wines with high acid and tannin structure like Cabernet Sauvignon and Nebbiolo for reds, or Riesling and high-end white burgundy for whites. On the other hand, you run the chance of the soft material breaking or becoming “corked,” where rotting occurs and creates a distinct smell of wet, musty cardboard. Other kinds of closures have been popping up to try and mitigate this risk.
  1. Synthetic cork offers many of the same benefits as natural cork such as a classic aesthetic and breathability, without the risk of cork taint. It also takes pressure off of the natural resources of the Iberian Peninsula, mainly Portugal, where most of the world’s cork is produced. Traditionalists say that the petroleum-based product can bring a chemical taste to the wine, but this has yet to be proven.
  2. Screw caps are made of recyclable aluminum and are most widely used in Australia and New Zealand, even for high-quality reds. By keeping more air out than a cork product, the cap preserves the original characters of the wine from the day it was bottled. For this reason, screw caps work best for white wines or for reds meant to be drunk young (don’t need much time and oxygen to age in a bottle). While some people view the easy-to-open mechanism as a plus, others feel that it removes the sacred ceremony of uncorking.
  1. Glass closures, branded as Vino-Seal or Vinolok, create a completely hermetic seal. This airtight option uses a glass stopper with an o-ring and further reduces the risk of oxidation while preserving the wine’s aromas. The main downside with this method is cost since the stoppers are usually manually inserted and run at a relatively high price per unit.
  1. Canned wine, while still a tiny portion of the wider industry, it is one of the fastest growing categories thanks in large to the millennial wine drinker. The main perk is that cans can be brought to places that bottles and glasses cannot, like beaches, parks, and campsites. Not to mention cans are easier to recycle than glass and come in a wider variety of sizes. Non-believers feel that can lack romance, or that the aluminum, despite being coated inside, may reduce aromas of the wine and affect the taste. However, the can does help to limit light and oxygen exchange, helping to preserve flavor and increase shelf life. This article recommends pouring the canned wine into a glass (or portable cup) so that you can still get the full experience, scent, taste, etc. The verdict from sommeliers and wine critics still seems to be out on this one, but the user-friendly product continues to increase in popularity with consumers year after year.
Layers of cork bark, Portugal 2018

Personal preference and tradition aside, it’s no longer the case that high end, high-quality wines must have a natural cork closure. Looking into the future, using alternatives to limit the number of corked bottles can decrease waste and saves money for wine producers. Maybe consumers will decide that cracking open their favorite can of wine is a fair replacement for the uncorking ritual, and Portugal’s cork tree population can be relied on at a more sustainable rate. Maybe those clinging to natural cork will find a way to recycle the material so that the industry doesn’t have to rely on plastics.

At least standing in the wine aisle can become easier with just a little bit of knowledge. If you want to drink that screw cap Pinot Noir with dinner tonight, great! If you want a Pinot Grigio that tastes as fresh and fruity as the day it was bottled, and it has a glass closure, awesome! Here in the Edna Valley, our local wineries use a wide variety of closures depending on the varietal and winemaker’s style. If you’d like to learn more and taste these different wines in person, go ahead and schedule a tour with us. We’d love to share an education excursion with you!