Archive for June, 2007

Q: Does the type of cork affect the wine?

Question from Don: Does the type, brand, manufacturer, etc. of a cork used to seal a wine bottle have an impact on the wine in that bottle? Thank you.

Reply: Hi! Thanks for writing! What an interesting question.

I’ll assume that you’re asking about natural cork and say the answer is “yes.” The job of the cork is to protect the wine from air without imparting any flavor of its own. The cork can have a positive impact on the wine, when it does its job well, by allowing it to age, and a very definitely negative effect when it fails and the wine spoils. If the wine is intended for very long storage, the winemaker will likely select a relatively long, dense, high-quality cork. For short-term aging, the quality should still be high, but extreme length isn’t really necessary.

As with wine, there are numerous factors that contribute to overall quality, starting with the agriculture. Portugal is the biggest supplier of the world’s cork, but there are other choices such as Spain and Sardinia. Where the tree grows and how it’s nurtured until it’s old enough to produce wine cork, around 40 years of age, is key. Attention to detail at harvest and when sorting is also important. And then, there’s processing and quality control along the way.

Wine Cork Testing

It appears that, at least in Portugal, most of the forests are family-owned and that the cork suppliers contract with the families. In the case of our supplier, Cork Supply USA, the cork buyer works with the families throughout the year and, in a recent demonstration, we saw that he hovers over the men who harvest the bark while the work is done. As you might guess, some companies will show greater attention to detail and be more involved than others. What about the company that lets growers be growers and just collects the bark?

And then there’s this whole issue of cork taint. As you’re probably aware, the industry has been struggling with it for many years. By now, it seems that cork taint (TCA) is on the run, but each supplier has slightly different methods of decreasing or eliminating the taint. In this article one supplier kind of took a pot-shot at another supplier’s approach.

Our supplier has a greatly-improved ability to detect TCA in whole bales of cork, thanks to working with a local wine lab that uses “solid-phase microextraction”. And they’ve developed a machine that purges TCA down to the level of 1 part per trillion (human threshold is 4 to 8 parts per trillion for most of us). So, you can see why we choose to work with them.

All of this is good news, because the overall incidence of cork taint is way down, now, and hopefully completely on its way out. And with cork taint out of the picture, natural cork has otherwise been an excellent seal for many centuries. Some are denser than others, some have more or fewer flaws, but most suppliers give the buyer the option to choose. My guess is that most of these suppliers are doing a good job or they’d be out of business. But, just as with wine, some are probably doing a little better job than others, and it’s our job as wine producers to track down the best.

There’s a little more detail on TCA detection and extraction from this previous
post
, and if you’re in the mood to immerse yourself in the world of cork, you’ll enjoy this 4-part interview with our supplier. I hope this is helpful to you! Cheers! Nancy

Take it off… Take it all off!

I recently had the opportunity to witness the performance of two professional Portuguese strippers!! Without musical accompaniment or mood lighting, father and son team Sergio and Joaquim took it all off, repeatedly and with gusto, after a long flight here from Portugal. Most impressive! ;-)

Our Winemaker, Geoff Gorsuch, has been fortunate enough to spend some time in the cork-oak forests of Portugal but, for the rest of us, Cork Supply USA, our cork supplier, brought the action here and demonstrated live the ancient art of denuding the cork-oak tree of its bark.

Sergio and Joaquim brought along some friends who happened to be cork-industry experts including Dr. Macku, PhD in agricultural and environmental chemistry, Sao Santos Silva, an expert in forest engineering and Frederico Mayer the Purchasing Director for Cork Supply and each enlightened us in his/her area.

Should be no big surprise department: their concerns are extremely similar to ours, as growers and winemakers. It’s all about putting the right tree in the right place, taking good care of it and harvesting with care. Aside from numerous references to sorting, there was virtually no discussion of drying, purification or other production methods because while important, as with wine, the quality is determined primarily by the raw material.

Proper Cork Harvest

And, as with viticulture, being good stewards of the land is an issue that’s front and center. We learned that the forests serve 3 main functions:

1. Cork production, by far the most important function.
2. To produce secondary crops, many naturally existing, such as medicinal wildflowers, honey and mushrooms.
3. To preserve grass lands and open space providing a side benefit of wild game such as boar.

The forests are also host to a number of migratory birds and some endangered species such as the Iberian Lynx and the Spanish Imperial Eagle.

These forests or plantations are nearly all family owned, but are subject to national regulations regarding the growth and management of the trees, harvest cycles (every nine years), pruning, thinning and tree removal. Land conversion is forbidden. Once a grower, forever a grower.

These knowledgeable presenters, with their charming Portuguese accents, gave us the ins and outs of soil and climate, managing the forests and how the trees reach the point of harvest. And then the floorshow began! Sergio and Joaquim flexed their biceps and picked up their axes.

We were all surprised to learn that there are some cork oaks growing right there, in the parking lot at Napa Valley College. Perhaps not an ideal habitat, but how convenient! When asked about growing the oaks (Quercus suber) here, Frederico indicated that it can be done, as we could clearly see, but the quality will not be good enough for wine corks -we’d be doomed to grow bulletin boards or something mundane like that.

Important fact: If the tree is harvested properly, it is unharmed and the bark grows back.

Proper Cork Harvest

Sergio and Joaquim led us to tree number one, an unwilling virgin oak, never before harvested, at about 20 years of age. When they discussed recent innovations it was mentioned that a specially-designed chain saw can be used these days, but in this case the traditional ax was the tool of choice.

Drum roll…

Poor Sergio and Joaquim! That tree did not want to give and the bark came off with considerable difficulty and in pieces. Frederico commented that the youth of the tree could be a factor and also we may not have had enough warm weather here for the bark to loosen its grip to the tree adequately (harvest in Portugal is usually from mid-May through mid-August and will be about 1 month late this year due to a rainy May). Not an auspicious beginning, but our strippers were undaunted. On to the next tree!

Sergio and Joaquin

The next beauty was 30-ish, had seen the ax once before and knew how the game is played. It submitted to the expertise of our strippers and shed its bark in two lovely, symmetrical pieces and in a matter of just a few minutes. And a few trees more…

Proper Cork Harvest

Now, Sergio and Joaquim are shy, soft-spoken, rather compact men, but don’t be fooled. They have to have the arms of King Kong to pull off a job like that over 3 months! No heavy breathing and they didn’t even break a sweat!

What a morning! It’s like everything else in life: whatever the topic, there’s a lot more to it than you ever thought…  Many thanks to Cork Supply and to Sergio and Joaquim, et al, for a most informative and entertaining session! Next time I think I’ll bring my boom-box to get the trees in the mood… A sia saide!

PS: For some general information on how the cork gets from the tree to the bottle, soon to be expanded and updated, thanks to the excellent information from Cork Supply, click here.


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