Those of you who know me, know that she got a rather lengthy and robust reply. The answer to this question can be simple and succinct if given by some wine makers. I’ve had a well respected wine maker blatantly tell me “Screw cap is the best closure, hands down”, after he drilled me on my choice of premium cork closures.
Of course, I don’t agree with him.
Often when I am asked this question I reply “What is best? A butter knife or a cleaver/chainsaw?” (I use these interchangeably, depending on how snarky I am feeling…)
Truth be told, the answer to wine closure is complex and variable. Many wine makers espouse certain attributes to closures, with very little science to back up their opinions. I use both screwcap and natural cork, and I am forever searching for data that can help me make a better decision on closure.
There is a study being done right now at UCD by a wine chemist named Waterhouse. I am very excited to see the published results on this study. The study is being done on Sauvignon Blanc, and within a two year period of time. It will feature 600 samples with a variety of closures. The analysis will focus on the wine chemistry but will also undergo a sensory panel, hoping that the chemistry and the sensory analysis will deliver some conclusive data. The questions that immediately come to my mind have to do with O2 pick up and integration over a longer period of time, and in red wines as well. Regardless, the results will yield an academic analysis that could help predict conclusions, one hopes. At least we might have a better understanding of how each closure type performs outside of the manufacturer’s claims.
For now, the contributing factors that might determine the kind of closure for wine would be varietal, aging potential, the presence of VA, price points, and package handling, along with other more specific factors. Tradition plays a vital role in using cork and tin capsules; the perceived value of wines plays a huge role in the choice of closures for premium wines and their branding.
Screwcaps have become mainstream in a large array of markets as wine closures. Almost all value wines are screwcap these days, as well as some reputable wines in the over $20 range. Not only is the screwcap convenient for the consumer, it provides a virtually oxygen free environment for wines, allowing the dynamics of wine to be nearly stopped due to oxygen pick-up. It is for this reason that most winemakers would choose a screwcap closure; the wine is less likely to change over time with a screwcap.
Other positive attributes of screwcaps;
- less TCA, or cork taint
- about 1/8th the cost of premium cork and tin capsules
- ease of opening, no tools required!
- They come in multiple cap linings for specific applications
- wine is stopped in time, leaving fermentations aromas relatively unaffected
Some negative attributes of screwcaps;
- perceived value of wine is lower than cork
- difficult to dispose of in a sustainable way
- screwcaps are a mined metal, requiring water and human resources that are not easy to trace and endorse as a sustainable industry
- screwcaps enhance reductive wines
I have to begin by stating that I use premium natural cork when I use cork. However, a quick (biased) discussion of synthetic cork might be warranted here. Synthetics have a long history of being unreliable as a closure that allows too much oxygen pick up, and inconsistent pressure requirements to remove. Have you ever had to remove a synthetic cork with all of the muscle you can manage and still not get it open? Personally, I think that they are ugly and cheap, but the shoddy performance of synthetics far out weighs the cost of real cork in comparison.
I am a fan of premium cork for so many reasons, but I have to say that the primary reason is purely visceral. I like them. They are aesthetically pleasing. Difficult science, here, I admit! But my bias ought to be revealed.
I get my cork from Portocork, a Portuguese company. This company uses their own cork groves that they have been managing for decades, sustainably and now without pesticides. Every single bale of 10,000 corks are tested for TCA using GC/MS for TCA. TCA, or cork taint, was once considered as a flaw solely attributed to wine via cork, but now we understand that screwcap wines can have cork taint derived from the winery. This is usually the result of chlorinated water in contact with treated wood products. The 2,4,6-Trichloroanisole (TCA) is aspirated in the air and can easily land in an unsuspecting tank of wine. Some wineries have ambient TCA floating around and landing in bottles, tanks and equipment. TCA was found in corks due to the treatment of cork using chlorine products. My cork company uses hydrogen peroxide now. With a rather rigorous detection program, I have found that less than a case of wine is returned to me as TCA flawed in a year (PLEASE return suspected cork taint bottles to us! We will always replace them, if we can!)
Other reasons to use cork closures
- tradition, tradition, tradition!
- Ageable wines require a tiny gas exchange over time that cork delivers
- absorption of volatile aromas, some not so good!
- Withstood the test of time (the oldest corked wine is 816 years old!)
- Sustainability in production, recyclable, reusable
Some negative attributes of Cork
- quality cork is VERY expensive (I pay $.39/cork vs. $.06 for screwcap)
- Cork Taint! (smells like wet cardboard or mouse)
- necessity for capsules (I pay $.32/tin capsule…totaling $.71 PER BOTTLE!)
- allows for oxygen exchange during bottling
- can suck up or remove lovely young wine fermentation aromas
Again, I use both screwcap and cork. I like them both, for the particular application I have chosen. My premium red wines go into high end bottles, with premium cork and capsules. My quick to drink wines, including whites use a screwcap to retain the youth and freshness of the wine without the added expense of cork.
TCA should not be the only reason to choose screwcaps. As Ol’ Abe once said “If the only tool you have is a hammer, you tend to see every problem as a nail.” Keeping an open mind in winemaking keeps our tool box full!