Cork Taint in a Screwcap?

In my last post, I wrote about the difference between corks and screwcaps, about how the latter has significantly circumvented the problem of cork taint. Then the unexpected happened to me - I got a screwcapped wine that was corked!

One of these was corked

It was a gorgeous summer afternoon in Portland, and I was thrilled to find a new wine bar and bottle shop to try. We sat down at the patio, and I ordered a flight of three mid-range Oregon Pinot Noirs. I swirled the glass of the first wine, took a whiff, and immediately got that faint but unmistaken smell of wet cardboard. I took a sip, which confirmed that off-putting taste devoid of fruit and flavor. I tasted the other two glasses, and they were fine.

I took the corked wine back to the shop and waited patiently for the shopkeeper to finish his conversation with another customer. Then I told him discreetly that the wine was corked. He took it back and came out to the patio with a new bottle and a new glass. He twisted the screwcap off the bottle to pour me a new glass and said, "That wine was fine, but here's one from a newly opened bottle."

Now, I have up to now experienced only half a dozen corked bottles. While it was not a common occurrence to get a corked wine these days, the last three happened in the past year so I am unfortunately quite familiar with the smell and taste of a corked wine; the earlier two being a Brunello and a California Super Tuscan-style red. I have even tried the Saran wrap trick to remove the taint, which, I am sad to report, does not work.

I digress. Now how does a screwcapped wine get corked?

TCA

I mentioned in my last post that the main cause of cork taint is TCA (2,4,6-trichloroanisole), a compound that leads to a musty fungal or wet cardboard aroma.  TCA belongs to a family of volatile compounds called haloanisoles, that cause moldy aroma. There are other compounds (TBA, TeCA, and PCA) that may be responsible for the taint.

Haloanisoles may be transferred to the wine from contaminated materials in the winemaking facility, such as tank coatings, hoses, barrels, and oak chips. It can also be transferred to the polyethylene film, which is commonly used as a liner for screwcaps. So while opting for a screwcap over cork will significantly reduce the chance of cork taint, it does not eliminate it. In my limited sample size, it is one to five.

Here's another interesting factoid - the sensory thresholds of different tasters for haloanisoles may vary as well. So one taster can be highly sensitive to it while another may not find it quite as objectionable. A well-known sommelier once discovered that a rare and expensive bottle ordered at his restaurant was corked. Despite his offer and attempt to replace it with a different bottle, the diners claimed that not only was the wine fine, but it was delicious. At which point, he had to back off against his professional judgement.

My Verdict: Regardless of the closure used, if you believe that your wine is corked, trust your taste and take the wine back. Even if the wine merchant disagrees with you, he or she will likely still replace your wine. It is better than to be stuck with an off-putting wine.

Corks or Screwcaps?

Since the sudden rise of cork taint in the 1960s, the wine industry has been exploded with alternative closures to seal bottled wine. The main cause of cork taint is the presence of a compound known as TCA (2,4,6-trichloroanisole) that leads to a musty fungal or wet cardboard aroma in the wine. While it is not harmful to the consumers, it definitely takes away the pleasure of enjoying a nice glass of wine.

Among the alternative closures with their corresponding pros and cons, the screwcaps in particular have gained quite a bit of traction in the new world, especially in Australia and New Zealand. While I am partial to natural corks for my cellar-worthy wines, summer calls for easy drinking. And who wants to fuss with a corkscrew at a picnic when you can twist the cap off a bottle of fresh Marlborough Sauvignon Blanc and seal it shut again?

Rulo Winery in Walla Walla only use screwcaps 

While screwcaps remain a favored alternative, one common complaint is that it does too good a job of keeping oxygen out and does not allow the wine in the bottle to breathe and mature. This can sometimes lead to "reductive taint" or the smell of rotten egg in the wine. However, winemakers are getting good at correcting the problem by adjusting the amount of sulphur dioxide added to the bottle prior to closure. (Yes, sulphur dioxide is often added during bottling to stabilize the wine, but that is a topic for another day.)

For cellar-worthy wines, a little oxygen over a period of time helps the wines develop and mature in the bottle. Contrary to popular belief, natural corks do not allow outside oxygen to enter sealed bottles. But because corks are made up of mostly hollow cells, oxygen from the corks themselves is gently and gradually released into the bottles to further age the wine.

As one might expect, the technology of screwcaps has progressed to offer a small amount of oxygen leakage from the cap into the wine, mimicking the same function in a cork. So we may see more and more cellar-worthy wines using screwcaps in the future. In fact, there are some wineries who have gone completely screwcaps for all their wines, including those that you can lay down to age. Rulo Winery from Walla Walla is one such winery.

With a steeper competition for closures, cork producers have also come up with more stringent procedures to reduce the incidences of TCA, like ensuring proper harvesting and treatment of cork. In addition, technical corks (which are essentially cork-based closures) are often treated to prevent TCA and available as less expensive options. In fact, I use technical corks for my homemade wine.

A mix of natural and technical corks

My Verdict: Just as there is a wine for every occasion, there is a closure that fits every type of wine. My rule of thumb is that if you drink your wine young, a screwcap is not necessarily a bad thing. But I would probably pause if I see a screwcapped bottle of Barolo or Burgundy. However, if you trust a particular winemaker, then it may be worthwhile to keep an open mind about his or her choice of closures.