Corked (Part 2)

As you may recall from last week's post, we recently opened a bottle of the 2006 Calera Cuvee Pinot Noir and were surprised to see it closed with a glass Vino-Seal.  Ever the trooper, Kerith picked up the phone and called the winery.  While the first person she talked to was friendly and helpful, her questions were a little too probing, so her call was turfed straight to famed pinot-master Josh Jensen.  Now, on with our story.  

Historically, corks were bigger.  Obviously this is a situation where greater length and thicker circumference make all the difference.  In aeons past, the great chateaux of Bordeaux shipped their wares to Great Britian by sea.  In the hulls of unrefridgerated ships, heavy, dark glass bottles with thick, long cork stoppers endured year round journeys, through summer's heat or winter's chill, all to satisfy the Brit's insatiable appetite for "claret."  Sometimes the goods received were perfect, but other times bottles from the same vintage of the same vineyard arrived as bitter, brown vinegar soup, hence the adage, "there are no great old wines, only great old bottles."  Today vintners employ glass bottles that are thinner and lighter and, yes, cheaper.  Even the corks are on average 10 mm shorter, sometimes even 15 mm shorter, of lesser grade, and so cheaper too.  This inevitably increases the incidence sporadic bottle oxidation, ruining a wine before it reaches peak maturity.

Researchers today aim to create an infallible, reliable seal that is impermeable to oxygen over time.  An ever-expanding coterie of unique closures now floods the marketplace, many of which are backed by scientifically rigorous trials.  The first screwcaps were issued by France in the 1970's.  Despite early research demonstrating no discernable difference in Bordeaux capped with screwtops vs. corks, the "Stelcaps" were scrapped after strong market resistance and failure of their liner materials.  The screwcap was redesigned in the 1990's, with a sleek exterior veneer camouflaging the cheesy telltale rings.  This omnipresent model successfully has topped our vino ever since.  By 1995, Switzerland was using over 10 million per year!  And France?  In 2002, Michel Laroche closed his Grand Cru Chablis Le Clos with the now ubiquitous twist-off.  By 2005, over 80% of all Australian whites were topped with screwcaps.  Today, the wine shelves at Vons are teeming with them. 

Battling head to head with the screwtop is Diam's synthetic "corklike" alternative.  Diam was developed by Sabate, the world's second largest wine-closure manufacturer.  So certain of the superiority of their synthetic closure, in 2005 Sabante boldly sold off its natural cork business altogether.  No TCA taint has been reported to date with Diam closures, and the wine within appears to retain its full spectrum of gustatory nuances.  With its oxygen barrier nearly foolproof, only time will dictate whether the Diam closure can withstand 10 or 20 or even 40 years of aging.

In May of 1999, the Aussies instigated a scientifically minded wine closure smackdown that pitted natural cork against Diam, agglomerate cork, and screwtop closures.  All in all, the Australian Wine Research Institute (AWRI) tested 14 different wine toppers to close the same unoaked semillion.  At regular intervals, the bottles were opened and closed, and the content tested by many parameters.  Degrees of oxygen permeation and sulfur dioxide depletion were dutifully noted and recorded.  In the end, when the numbers were crunched, the screwcap was the undisputed king of the oxygen barrier.  Oxygen permeation in the screwcap bottles shifted between 0.0002 and 0.0008 mL/day while the cork closures oscillated wildly between 0.0001 to 0.1127 mL/day.  Obviously this degree of variability is unacceptable.  With natural cork, it now becomes highly probably that one bottle may suffer premature oxidation while its neighbor may not.  Yet we cannot decipher which is which until the wines are decanted, and it's too late.

Portugal's cork industry, of course, dismisses this research as rubbish, as do other well known wine researchers in Europe and Australia.  However the fact remains that cork's performance vacillates significantly.  All wine closures permit minute amounts of oxygen to enter the wine at bottling; it is likely consumed by chemical reactions within days to weeks.  As such, wine closure devices should be ranked by degree.  A small degree of oxygen settling into the wine at regular intervals over time will not hinder a wine's aging potential.  But variable or greater amounts of O2 are problematic.  As oxygen is dissolved and the preservative sulfur dioxide depleted, the wine matures, phenolic compounds are altered, and its shelf life is depleted proportionally.

The yin and yang of the GCD is more ephemeral and difficult to quantify.  It seeks to discriminate between the effect of cork vs. synthetic closures on the organoleptic qualities of a wine.  How is the taste, aroma, flavor, or mouthfeel affected by different closures?  And can we trust scientific studies that hinge on personal palate preferences?  And what about Mr. Jensen's Vino-Lok?  That clever glass closure was awarded a photo and a caption in my most current wine text but did not yet merit a discussion in the body of the text.  Halliday and Johnson write "The Vino-Lok glass stopper (and attendant capsule) has aesthetic appeal, but has not been in use for sufficient time to prove its long-term seal capacity."  But if it's good enough for Calera, it's good enough for me.

Frustrated by an "unacceptably high" prevalence of sporadic cork taint in any given vintage, Mr. Jensen sought out better technology, starting with screw top experiments in 2002.  Following two years of intense discussion, the Calera wine company instituted the glass Vino-Seal closures in 2005, on trial basis for their viogniers.  By 2006, all of their Central Coast pinots were sealed with these glass stoppers, as well.  Today the viogniers, chardonnays, Central Coast pinots and the cuvee pinots are all topped with glass.  (Incidentally, the seals are called "Vino-Seal" here in the U.S. as Sutter Homes owns the term "Vino-Lock.").  Dora notes, "They hold up great, and people love ‘em."  We agree.  However, we didn't know the Vino-Seal is oxygen-resistant enough to preserve the spunk in a half consumed bottle of vino, at least overnight.  According to Dora, in the Calera tasting room, unfinished bottles are simply "gassed" with inert gasses (usually argon or an argon-nitrogen blend) and reclosed with the Vino-Seal for the next day's tourists.  We could shelve our own oxygen-sucking, air stopper device at last! 

To date, the greatest downside of Vino-Seal is the labor intensive bottling and significantly higher costs.  To correctly employ the stoppers, one must purchase compatible glass bottles, which are available exclusively though a company called Encore! glass.  While Encore! bottles are not overpriced compared to other glass suppliers, only 3 styles currently are available, with no half-bottles manufactured at all.  Plus a Vino-Seal closure runs 0.58 cents a pop while the highest grade cork tops out at 0.48 cents each, a significant difference over thousands of cases of wine, not to mention the man power required to gas the headspace and insert each Vino-Seal stopper by hand, bottle after bottle after bottle after bottle.  According to Dora, Calera employs a bunch of extra folks on the bottling line when the season arrives.  But why were a few cuvees still closed with traditional cork?  And who buys those bottles?  Are they VIP?  Or do they just like to live on the edge?

As it turns out, there is no mystery at all.  The cork-sealed allocation was specifically requested by a Japanese importer who presumably took all 10,000 bottles of cork-topped '06 Mount Harlan Cuvee Pinot Noir.  Mr. Jensen writes, "They are quite traditional and it's taking them time to get used to Vino-Seal, but we're nudging them in that direction."


Some pictures of the Calera Vino-Seal:



Ref: Halliday and Johnson, The Art and Science of Wine, Firefly Books Ltd., 2007