Wine Faults - Cork Taint and Vinegar

Cork is the traditional closure for a wine bottle. Yet one of its drawbacks is that it can actually cause a wine fault.  And, have you ever had a bottle of wine that "had turned to vinegar?"  Well both of these wine faults can ruin a bottle of wine. So let's explore the causes.

Cork taint is due to some degree by natural chemical compounds found in cork.  Known formally as 2,4,6-Trichloroanisole (or TCA for short), this compound, when combined with chlorine and mold can result in a wine that smells like wet cardboard, wet cement or a wet dog. And you don't want to smell these scents when drinking a wine.  It only takes a few parts per trillion to taint a bottle of wine. The results can also be very subtle. With faint levels of TCA, a wine will be striped of flavor leaving a normally rich, fruity wine tasting quite dull or muted.  Often it is so subtle that after drinking the wine you are simply left disappointed without being able to determine why.  Although the cork industry states that only 1% - 2% of corks may be tainted with TCA, Wine Spectator found in 2012 that 3.7% of the bottle they sampled were tainted, down from 9.5% in 2007.  So maybe this is the reason for so many disappointing bottles of wine.

In addition to cork taint, another wine flaw is finding a bottle of wine that has "turned to vinegar."  But can wine really turn to vinegar? The answer is technically yes. But not really.  Without getting into too many technical details, the reason that vinegar tastes like vinegar is acetic acid.  And acetic acid can form in wine when it gets 'infected' with Acetibacter bacteria. This bacteria occurs naturally in the air and on fruit. But it isn't really fair to call tainted wine 'vinegar' since it tastes really bad. It's not something you'd want to mix with olive oil and pour over your salad.

If you ever encounter a bad bottle of wine, as odd as it sounds, do smell it and learn from it. And especially if a wine server takes back a bottle after opening it without even pouring it, ask to have them explain how and why the wine is bad.  Use it as a learning moment.

A couple final thoughts. First, there are no negative health affects of drinking tainted wine.  But who'd want to? And, second, if you do come across a bottle of wine that has gone bad, know that you can return it to the store where you purchased it or, at a restaurant, send it back for another one. 

May all your wines be fresh and wonderful! Cheers!




Alternatives to Natural Corks

In recent posts we learned that cork comes from the bark of the Cork Oak and that the foil capsule covering the cork was originally put into place to protect the cork from insects and rodents.  So you might wonder is all this necessary today?  Aren't there viable alternatives to using natural cork as a means of sealing a bottle of wine?

The advantages of natural cork include its ability to compress and expand (it's malleability), its proven long-term ability keep a bottle sealed, its renew-ability (because, after all, corks do grow on trees!), and a cork does allow the bottle to 'breathe' and improve (sometimes) with age. 

On the downside, natural cork may be a renewable resource, but it is a limited resource as forests of Cork Oak continue to shrink around the world.  Additionally, cork is relatively expensive since the bark must be manually shaved off the trees and processed to make corks. Another downside to cork is that it is formed in nature and, therefore, its quality is variable. This variability leads to natural corks having different degrees of 'breathe-ability."  And finally, with a natural cork, there is a chance that a bottle of wine will become tainted by the cork (subject of a future blog).

So, what additional ways are there of sealing a wine bottle that do not involve natural cork?  Well the first alternative actually involves nature cork. To deal with cost and variability, 'technical corks' are produced by grinding up the scraps of cork bark that remain after corks are punched out of the bark, and this cork 'dust' is glued together, somewhat like particle board is produced. These technical or composite corks are less expensive to produce and more consistent in quality.

Another alternative to natural cork is synthetic cork. These 'corks' are made with polyethylene (plastic). These are cheaper to produce, do not use a limited natural resource, and do not lead to possible cork taint. Due to the fact that they don’t dry out, plastic corks are easier to take out the bottle and they won’t crumble into the wine. At the same time however, they are often harder to put back into the bottle because they are not as malleable as natural cork. And, because they are plastic, they are recyclable! Finally, synthetic corks are not for serious wine collectors who purchase wines for aging. This is because they do not allow the wine to 'breathe' while in the bottle.

The other alternative to natural cork is the hotly debated twist-off cap.  We'll get into this cork alternative next time. Cheers!

Behind the Cork™ Wine of the Week - Bogle Old Vine Zinfandel ($8)

Looking for an attainable, affordable wine?  You've come to the right place. Each week I feature just such a wine on the Behind the Cork Wine of the Week page of

This week's wine is Bogle's Old Vine Zinfandel. This is a really nice wine and a great value. It's got intense fruit flavors without being a big 'jammy' Zinfandel. It is nicely oaked and smooth.  It pairs well with anything from the meat aisle, along with any other food with bold flavors.

Why is There a Foil Capsule on a Wine Bottle?

Last time we looked at where cork comes from and learned that it's actually the bark of the Cork Oak tree. It is bark that can take 25 to 50 years to get to the point where it is usable for wine bottles and each tree can only be harvested every nine years so as to not do permanent damage to the inner bark of the tree.  But then there is a capsule that covers the cork and the top of the bottle. Ever wonder why there is a capsule on a wine bottle?

Originally the capsule was placed over the cork as a means of protecting the cork from insects and rodents that found the cork to be an enjoyable meal.  The capsule served as a barrier between the critters and the cork.  There are also some theories that the capsule was also a way of covering the cork from would-be wine thieves. The capsule kept unscrupulous individuals from being able to pull the cork on a good bottle, drink the contents, replace it with inferior wine and re-cork the bottle!  I'm not completely sure of this one, but it makes some sense. But, it certainly was the original reason behind the wire-netting that was used over some bottles of wines.

The wine bottle capsule, and wire-netting, continue to be used today. But not to protect the cork from critters or the wines from dishonest thieves. Today the capsule and netting serve purely as decorative elements of the wine bottle packaging.  This was abundantly clear during a recent visit to a small winery. While standing at the tasting bar, the owner came out with a couple different gold-colored capsules and asked which one looked best with their label.  After a bit of comparison with the colors on the wine label, it seemed obvious that one was the better shade of gold.  "Yes" the owner said, "but it's considerably more expensive than the other one."  I don't actually know which capsule they ended up choosing, but the capsule is all about packaging. And economics. 

Originally the capsule was made of lead. It was a very malleable metal that was easily formed into the proper shape. But, in the 1990's, it was confirmed that the lead left enough residue on the bottle's lip so as to be a potential lead poisoning health hazard to wine drinkers. So lead was replaced with tin or plastic.  There are also many wineries that are eliminating the capsule completely, or just placing a small dollop of sealing wax over the top of the cork.

One other bit of trivia regarding the capsule. If you take a close look at the top of the capsule you'll typically see one or two tiny pinholes in the cap.  These holes have been attributed to allowing the cork and the wine to ever-so-slightly breath over time. But the commonly accepted reason is much more practical.  These tiny holes in the top of a wine capsule actually allow the air to escape while the capsule is being installed. Without these 'vents' the air inside the capsule would become trapped and the capsule would not be able to fully seat on the lip of the bottle.

Well, that's a lot of information on something that we usually ignore and simply cut off before enjoying a bottle of wine.  So here's to pulling that cork and enjoying a nice glass of wine. Cheers!

Behind the Cork™ Wine of the Week - Columbia Crest Chardonnay ($8)

Looking for an attainable, affordable wine?  You've come to the right place. Each week I feature just such a wine on the Behind the Cork Wine of the Week page of

This week's wine is Columbia Crest Chardonnay. A great value at $8!  While the pendulum of Chardonnays has swung away from the heavily oaked "Big Buttery" Chardonnays, the Columbia Crest still gives buttery-oak Chardonnay lovers a viable option.  While the oak is bold and rich, it is not over-the-top. This is a great wine with seafood, chicken or a salad.

Where Do Corks Come From?

During a visit to the Dry Creek Valley in Sonoma California, I stopped at the beautiful Ferrari-Carano winery. After tasting their wonderful wines, my server stated that walking their gardens was not to be missed. And while in the gardens, he said to be sure to stop by and check out the Cork Oak.

I had always known that cork comes from a tree, but not much beyond that.  So, while strolling through the garden, I came upon the Cork Oak (Quercus Suber) shown in the photo.  In reading about the Cork Oak I was surprised by several facts.

First, and most surprising, was that cork comes from the bark of the Cork Oak.  I had always assumed that the cork somehow came from some soft inner wood of the trunk. But no. It's from the bark.  And then to learn that the bark can only be harvested every nine years, so as to not harm the tree.  The Cork Oak actually has two layers of bark. The outer soft, woody, bark and another inner bark that must not be harmed while harvesting the cork.

Another interesting fact is that cork trees can take 25 years before they are ready for their first harvest.  And typically this first harvest is not suitable for wine stoppers. The first harvest of cork is usually ground up and molded into large block for use as other cork products such as cork tiles and message boards. It isn't until the tree is approximately 50 years old, and on its third harvest, that it produces cork suitable for wine stoppers.

Finally, a Cork Oak can yield 13 to 18 harvests during its life of around 300 years old!

The Cork Oak is grown around the Mediterranean in Portugal, Spain, Morocco, France, Algeria, and Italy.  Attempts to commercially grow Cork Oak in other parts of the world have not been successful.

Whenever wine corks are discussed, the topic of synthetic corks and twist-offs comes up. And I'll hold off on that topic for a future blog.  But next time I want to address that beautiful foil capsule that covers the cork and the upper portion of the bottle. Until then, cheers!

Behind the Cork™ Wine of the Week - Kenwood Jack London Zinfandel ($16)

Looking for an attainable, affordable wine?  You've come to the right place. Each week I feature just such a wine that may be great for taking to a party, enjoying with a dinner or just sipping on Wine Wednesday. 

This week's wine is Kenwood's Jack London Zinfandel. This is a great one that I enjoyed with a short rib dinner. From Sonoma Mountain, this wine is described by the winery as having "fruity aromas of raspberry and fig combined with subtle notes of vanilla and white pepper. With its delicate and well-structured tannins, it provides an elegant mouth feel and a long finish." Another great one to try!