What if our resistance to change is nothing more than the acceptance of a habit?
Think about it.
A habit, good or bad, is a settled practice. A habit is not a tradition.
A tradition is a cultured practice that flows from times past to times present. To endure, a tradition requires a certain active quality. A tradition cannot be passive if its abiding wish is to survive.
Curiously, in European winemaking circles, the use of aluminium screw caps continues to meet with strong traditional resistance. For many ardent apostles of natural cork, the thought of screw-capping a fine wine is akin to betrayal, a culturally ruinous act. And yet, not surprisingly, traditionalists are as swift as anyone to curse natural cork when it fails…
Whatever be your language of damnation, for nigh on 60 years, cork taint and premature oxidation have haunted the use of natural cork stoppers. At the heart of matters lies a touchy subject: natural cork’s structural variability. You see, seal variability is a critical concern when bottling wine, especially bottles of a premium nature. With cork being the most revered stopper among the traditional elite, who among their ranks would ever be ‘so mad’ as to question its efficacy?
“Arise Gli Svitati!!”…
…a dynamic quintet of like-minded Italian winemakers determined to calibrate our understanding and appreciation of the oft-maligned alternative: the aluminium screw cap.
Loosely translated into English, Gli Svitati is a suggestive moniker, meaning a group of individuals afflicted by a kind of twisted madness; you could say, persons with plural-screws loose.
Ironically, when gathering for their inaugural media presentation at the Villa Sorio in Vicenza, there wasn’t a loose screw in sight. With proceedings underway, one by one, Silvio Jermann, Mario Pojer, Maria Luisa Manna & Franz Haas Jr., Walter Massa, and Graziano Prà recounted the personal journeys that brought each of them to embrace the un-traditional one.
As lifelong innovators, none of what was presented had been conceived or born overnight. For Silvio Jermann trials began more than 20 years ago! Mario Pojer’s first steps were taken in 2007, while for Graziano Prà it was 2010. The stories of Walter Massa and the Haas family echoed with similar refrains.
Adding an international flavour to proceedings, acclaimed Australian winemaker Kevin Judd was welcomed by video conference call from New Zealand. As co-founder of Cloudy Bay and the current owner at Greywacke, Judd is a longstanding advocate of the screw cap. With two decades of practical experience to call upon, his sage-like commentary was positively compelling. So too were the scientific submissions of Professor Fulvio Mattivi, of the Fondazione Edmund Mach, whose discerning data offered rich independent support to sustain the alternative cap’s claims. Completing the technical picture, supplementary insights and market overviews were furnished by representatives of the world’s leading screw cap suppliers, Amcor Stelvin, and the Guala Closures Group.
In fact, it was far from it.
When truth be told, the faults associated with cork are not entirely of its own natural making. It is we humans who must shoulder responsibility for one very noteworthy failing. Whether or not historical players will agree, let it be said; political, economic, and commercial interests have not always aided quality cork production.
If we return to the 50’s, 60’s and 70’s, we find a Europe in which post-world-war-two-economic-drivers were acutely focused on growing the mass market. The supply of mass-produced, heavily standardized goods was the new global objective. It was quantity at speed that reigned: not quality.
In adhering to new policy, many regrettable practices were ushered into play that adversely altered our understanding of ethical, sustainable, and environmentally friendly farming. Absolutely every agricultural field was impacted; cork oak forests were no exception. The ubiquitous use of pesticides, fungicides, herbicides, and wood treatments each proved to be a misguided choice, as was the introduction of antimicrobial chemical solutions for sanitizing wine cellars and winemaking equipment.
With such an unwitting cocktail of applications, extending far beyond responsible, one major downside-effect was soon to be exposed: cork’s susceptibility to taint.
Forthwith, a brief explanation.
It’s triggered when the filamentous fungi, which naturally reside in cork’s small air spaces, become exposed to the chlorophenol compounds contained in manmade biocides (i.e., pesticides, fungicides et al). The filamentous fungal reaction is nothing other than a natural form of fungal self-defence, as the fungus seeks to neutralize the presence of the chlorophenols.
The fact that TCA, and the analogous taint known as TBA (2,4,6-tribromoanisole), are not naturally occurring in nature is a hugely significant consideration. It means the existence of cork taint is not due to the presence of natural filamentous fungi but rather to the contamination of cork tree bark and wood by synthetic chlorophenols such as TCP (2,4,6-trichlorophenol).
Cutting the long-sad-story short, once contaminated with TCA or TBA, a good wine’s fate is abruptly sealed. Destiny is swift to call it by its heartbreaking new name: unpalatable waste.
Of course, in the years since this distasteful discovery, notwithstanding the vast improvements made in cork forest management and cork production, the issues associated with cork taint remain. You see, it has been found that chlorophenol residues are extremely slow to degrade in nature. Seven decades have already passed with little evidence to foster much hope. Adding to the conundrum, one must also consider the lengthy 9-year period that lapses between individual cork tree harvests. However it might one day play out, for now one is left with little choice but to view the annual financial losses due to such cork-related flaws as none other than an incurable constant.
Cork industry commentators suggest the annual level of flawed waste is now down to 1-2% of production.
(Source: Tom Jarvis, Wine Searcher 2019)
According to other independent sources, it may well be between 2-5%.
(Source: Jamie Goode, Flawless 2018).
Much remains to be learned about the level of unreported consumer experience.
In the interest of maintaining clarity, let it be noted that natural cork is not alone when it comes to the issue of tainting. Both TCA & TBA have been uncovered in wine cellars, among contaminated hardwood surfaces, including woods that are used in barrel construction and/or other wooden storage and shelving systems.
Of course, regardless of the source of the taint, it’s with the cork stopper in hand that the wine consumer will encounter the aroma of musty disappointment. And once encountered, there’s no surprise when consumer reasoning begins to critically question bottling practices and especially cork stopper selection.
Reasonable consumers wonder why?
Like, when faced with the choice of bottling wines with a predictably flawed material or deciding to change to an untainted alternative, why do so many industry players appear so emotionally invested in trying to make natural cork stoppers fit-for-purpose?
Is it really a matter of maintaining tradition?
Or, might it simply be the blind acceptance of an economically wasteful “habit”?
In the early 1960’s, out of necessity, the screw cap was envisioned as a taint-free wine bottle closure. Subjected to countless trials and international studies, by the late 1990’s, its suitability as an alternative wine bottle closure was successfully proven. Many in the global winemaking community have since heeded the good news.
According to current supplier data, aluminium screw caps now account for 37% of the annual global order of +30 billion wine bottle closures. While 54% of winemakers continue to choose natural cork, usage has apparently declined by -7% since 2015. In the same period the demand for screw caps has actively grown by +9%. (Sources: Amcor Stelvin & Guala Closures Group 2023 / Euromonitor 2021).
It’s worth noting that in tandem with the upward turn in screw cap usage, other technical closures like DIAM and Ardeaseal are also gaining a foothold.
[Quick back-track: If we accept the indication that cork taint results in annual losses of 1-2%, then what does 1-2% of 54% of circa 30 billion closures actually look like? Well, it would be 162-324 million bottles of wasted wine per year. Hardly a trivial number. Indeed, one imagines such levels of waste would be untenable in any other industry. So why is it that the wine world and wine consumers are still prepared to accept it? To sustain tradition? Really?].
To understand the modern dynamics, we must first return to the screw cap’s place and time of origin. Curiously it was designed and developed in tradition-rich Europe. To be precise, it was conceived in the R&D department of Le Bouchage Mécanique, Chalon-sur-Saône in Burgundy, France. As history recalls, the prototype was first registered in 1959 (Source: Amcor Stelvin).
A key stimulus for the research and development came from Switzerland where winemakers urgently sought an alternative closure. In those years cork taint was plaguing Swiss Chasselas wine production. While no-one could be sure of the precise cause, the cork stoppers were deemed ‘obvious culprits’. A speedy solution was needed and the first working screw caps were made available for trial in 1964. By the early 1970’s the initial trials had been successfully completed. Chasselas, and its Swiss custodians, no doubt celebrated.
Yet, despite the early positivity, further European interest in the screw cap was surprisingly unforthcoming. Instead, it was to come from the southern hemisphere where inquisitive Australians began trials of their own in 1973. Continuing throughout the 1970’s, even when high profile winemakers like Yalumba and Pewsey Vale began bottling and promoting the new cap’s credentials, sadly Australian market research revealed significant consumer apathy (Source: Damien Wilson, Case Study 2010).
Undeterred by the prevailing consumer sentiment, winemaker interest in the screw cap remained strong. Technically the trials had proved successful. What’s more, consumer awareness and future acceptance had been primed to grow. And as history so often teaches us, it was only a matter of time before the sentiment would change.
And it did. With dependable quality cork supplies becoming increasingly difficult to source in the 1980’s and 1990’s, wineries in Australia, and by now also in New Zealand, were quick to switch to the proven alternative.
With both Stelvin screw caps and the specially threaded BVS bottles (Bague Verre Stelvin) readily available, the enlightened few soon charted the path to screw cap acceptance.
Today in the Austral-Asia trading area, the twist-off experience has reached an impressive +77% market acceptance. In terms of the Australian market alone, 87.9% of all wines produced in 2018 were sealed with screw caps. Looking specifically at Australian white wines and you’ll find screw cap usage has grown to 97.3%.
(Source: James Halliday Wine Companion 2018).
Winemakers down under have come to understand that managing wine spoilage and wine waste are essential to maintaining winery efficiency and customer satisfaction.
Since 1999, ongoing studies by the Australian Wine Research Institute (AWRI) have demonstrated beyond doubt that the gold standard long-skirted screw caps (60mm x dia. 30mm) do indeed resolve the headache of cork taint. They have equally proven screw cap effectiveness in countering issues of premature oxidation (PremOx), which is achieved by limiting the absorption of atmospheric oxygen through the use of the cap’s internal liner seal.
The liner seal materials, known commonly as SaranTin, Saranex and the most recently introduced, ALKOvin, are cut into small discs which are fitted inside a cylindrical aluminium sleeve. The sleeve is then carefully pushed onto the open bottle’s rim, with the seal and finished cap simultaneously being formed around the neck of uniquely threaded BVS bottle.
Critically it is not the aluminium but rather the liner seal material that delivers the screw cap’s key functionality. With the nature of today’s liner seal materials, winemakers are now afforded the possibility of choosing an oxygen transmission rate (OTR) to suit their winemaking needs. For example, a SaranTin liner typically offers an OTR of 0.0mg O₂/year (meaning it’s effectively a hermetic seal), while the Saranex liner can offer OTR’s of 1.0 to 1.5mg O₂/year. Of course, each cap supplier provides its own range of options. For example, the Stelvin Inside brand offers 4 different OTR’s as part of their standard program.
Such advances in screw cap technology mean that preserving wine flavours, aromas, and freshness has now become a fully active process; “active” is the key word. No longer is it a question of following the traditionally passive approach of sealing with cork variability and hoping for the best.
Worth noting, there are several other technical closures offering OTR’s ranging from 0.3 to 1.0mg O₂/year, making them comparable to screw caps. Other synthetic stoppers that are available have been studied and found to have higher OTR’s, even up to 20mg O₂/year. (Source: Volker Schneider 2021)
As outlined, by choosing a specific screw cap liner with a pre-determined OTR, winemakers can now confidently craft an age worthy wine style. Whether they choose a typical oxidative or a more reductive approach, it is the screw cap’s OTR and structural certainty that provide the necessary assurance, allowing winemakers to actively assume control of their wine’s so called bottle evolution.
In direct comparison, natural cork is generally accepted to have a higher structural variability. After all, as a natural product it is only natural that it does so. Indeed, when cut and selected, each cork stopper is uniquely different, bestowing a unique evolutionary potential on each sealed bottle. Amazing as the evolution of cork-sealed wines can be, its the structural variability of the cork stopper that can lead to the aforementioned 1-2% disappointment.
Added to this, historical studies revealed how the OTR’s of some natural corks were found to vary widely between 0.5mg and 23mg O₂/ year, with strong fluctuations being observed between individual batches, as well as between individual stoppers within a batch. (Source: Volker Schneider, Journal of Viticulture and Enology 2021).
With this kind of natural variability across a wide potential range of oxygen transmission rates, the issue of PremOx for an “indeterminable percentage” of bottles remains a concern for users of natural cork. It’s just the way it is. Producers and consumers are encouraged to keep each other informed when faults are encountered.
Well, as previously alluded to, the global spread of screw cap acceptance is entirely non-uniform. The +77% acceptance in the Australasia market exists in marked contrast to the screw cap’s place of origin. Europe-wide acceptance stands at a listless 34%. While in Italy, home of Gli Svitati, it’s floundering at 20%.
(Source: Amcor Stelvin & Guala Closures Group 2023)
In 2023 it’s hard to find a convincing explanation for Italy’s enduring resistance. Without open discussion, those trying to reason ‘why’ are left to speculate. And so ‘speculate’ one must.
Superficially speaking, there appears to be a heavy measure of misinformation about the screw cap’s technical capability. Most likely born from a lack of first-hand experience. Sadly, ill-informed hearsay tends to sustain traditional intransigence.
Furthermore, insubstantial comments which suggest the idea that “aluminium screw caps lack the emotional sensitivity of natural cork” or that “screw caps are unsuitable for high-value products”, are as misguided as they are unworthy.
To discredit alternative materials with such throwaway remarks is quite disingenuous. One would expect a more gracious and self-assured stance from those who espouse traditional values. After all, rather than being closed-minded, the advocates of screw caps are open to discussing and sharing their wealth of direct experience and scientific data.
It should probably go without saying, but let it be said anyway; the visible use of aluminium screw caps among many high-end producers of premium spirits, distillates, and perfumes, not to mention many of the great wines of the southern hemisphere, quickly dispels the misleading myth surrounding high-value products and screw caps. A move toward an assured quality alternative is precisely because high-end products need high-quality closure assurances.
By adopting such a highly visible stance Gli Svitati recognized the immediate need to demonstrate their quality intentions. And duly they did, as they put both their wine and screw cap sensibilities to the 100+ attentive audience test. In what was a novel tasting format, each winery presented a sample pair of wines, sealed years previous, using both traditional cork and aluminium screw cap.
1. Prà, “Soave Classico” 2010 – (this was the first vintage using screw cap)
2. Walter Massa, Barbera “Monleale” 2016
3. Pojer e Sandri, “Sauvignon” 2007 – (the first vintage using screw cap)
4. Jermann, “Vintage Tunina” 2013
5. Franz Haas, Pinot Nero “Schweizer” 2015
In brief, the performance of all five screw-capped wines was outstanding; the freshness, colour vibrancy, fruit, and aromatics of each wine was found to be splendidly framed and displayed.
Sadly, the same could not be said of the wines sealed with cork. While three-out-of-the-five performed exceptionally, regrettably two wines served were oxidized to a point beyond drinkable.
[Special Note: The tasting experience I had was shared by those guests seated nearest to me. The real-time bottle opening and service was intended to mirror how a consumer would encounter these wines immediately upon opening, defects if they occurred were included. The wineries were endeavoring to create a unique shared experience and I believe they succeeded. With more than 100 attendees, other tasting tables no doubt had differing experiences. I was more than satisfied with the authenticity and sincerity of this unique sampling.]
While obviously the two faulty wines were a disappointment for the two producers on hand, nevertheless it was this inconvenient truth that aided the twisting debate. In a semi-scientific way, I daresay a peaceful conclusion was reached; for the Italian and European markets to dispel the screw cap taboo, winemakers and consumers must expand the wine closure conversation to now contextualize the meaning of ‘traditional quality’ in terms of the closure’s ‘structural variability’.
Screw caps are neither a low-value nor a low-cost alternative.
On the contrary, they are a modern, premium packaging solution, providing a necessary and effective response to two of winemaking’s most troublesome issues. What’s more, they are a discerning, highly user-friendly alternative.
Yes, of course they are different to traditional cork stoppers. There’s no escaping it.
And yet, whenever open debate will be allowed to finally arrive at the necessary review of traditional artisan values, I again daresay one will be well able to argue how screw caps possess inherently strong traditional credentials.
If you take a moment to consider the impact that the introduction of screw caps has already had on the wine industry; how their mere presence in the market has led to an acceleration of much-needed improvements in the field of cork manufacture. Rather than viewing screw caps as somehow ‘anti-tradition’, why not reconsider how they are ‘actively’ bestowing benefits on both winemaking quality and tradition.
According to the International Aluminium Institute based in London, 75% of all the aluminium thus far produced on the planet remains in constant circulation. This is due to aluminium’s durability and excellent recyclability. In Europe, aluminium recycling levels are increasing, with recycle and reuse programmes in countries such as Germany already at an impressive 87%. The fact that aluminium can be recycled and reused, an infinite number of times without the loss of quality, is an undeniable factor in its favour.
Additionally significant is the fact that the processes involved in recycling require only 5% of the energy needed to manufacture primary aluminium. Producers and end-users of aluminium materials are actively taking notes of each other’s behaviour. Screw caps can easily be recycled with all other domestic aluminium containers. Just simply remove the liner seal.
Considering the available scientific data, it appears the ideal closure should be one whose raw material quality is high and whose structural variability is low. Ideally the closure should also allow the winemaker to actively manage the OTR over the desired evolutionary lifetime of the wine.
As outlined, aluminium screw caps appear to fit the ideal profile.
Indeed, all the independent research data presented by Professor Mattivi also appears to point to the aluminium screw cap as currently the only cylindrical wine bottle closure that can consistently stake this claim.
Of course no-one is saying that screw capped wines are defect-free. Faults including TCA & TCB taints, together with reductive off-notes, have been detected in wines sealed with screw caps.
However, when cork or wood associated taints are found in screw-capped wines, it can be stated, they are not caused by the cap. Discovery of such a defect immediately points to a winemaking related issue, most likely associated with cellar practices and/or a cellar equipment contamination (i.e., one that has manifested itself in the wine during the pre-bottling phase).
Unlike cork or wood taint, the presence of reductive off-notes and flavours have been commonly associated with the use of screw caps. This flaw tends to stem from extended periods of reductive bottle ageing (i.e., which is bottle ageing in the absence of any oxygen transmission through the cap).
During the early years of screw cap use, when the original SaranTin liner was the most regularly employed liner seal, it functioned as a complete oxygen barrier (i.e., with an OTR close to 0.0mg O₂/year). In the absense of any gaseous exchange through the cap, wines sealed with the original SaranTin liner could present with off-flavours and aromas associated with development of volatile sulphur compounds (VSC’s). In Australia, Riesling and Sauvignon Blanc were two of the white wines most often affected.
Though ageing under SaranTin can and occasionally does contribute to this flaw, it is now accepted that it might not always be solely due to the use of the screw cap. It is also understood that similar reductive off-notes may already have developed in pre-bottled wines. Once bottled and sealed the issue would be exacerbated by subsequent reductive bottle ageing. Discovery of such a fault will always require a more detailed investigation.
In light of the pioneering downsides, to negate the issue of VSC’s developing post-bottling, winemakers have since adapted and can now use other liners like Saranex, with OTR’s of circa 1.0 – 1.5mg O₂/year.
Indeed, as mentioned earlier, a new liner seal is available in which an active ‘scavenger’ layer has been incorporated, which is designed specifically to bind with and deactivate the presence of VSC’s in the bottle.
Known as the ALKOvin liner, it is produced by Meyer Seals in Germany and has been on the market since 2017. Offering a similar OTR to SaranTin, over the past 4-5 years, it has been successfully put to the test by the AWRI and independent winemakers in Australia and New Zealand. (Source: Meyer Seals 2021-2023).
As reductive faults are often cited as being the screw caps Achilles heel, it is only fitting to add one final footnote from Professor Mattivi’s data. It regards a 10-year-long independent survey carried out by the International Wine Challenge (IWC) from 2007 to 2017, during which time +118,000 wines were submitted to the IWC for competitive tasting.
As part of their in-house review, the IWC judging panels recorded the percentage incidence of reductive faults in each of these wines and remarkably, wait for it, they discovered the incidence rate to be the same for each and every closure type, including screw caps.
While everyone would probably have expected the screw caps to be the worst performing closure, this result is an important turn-up for the books. Even if such a survey might contain the occasional false positive, this discovery points to an ‘interesting reality’ where reductive faults (i.e., the presence of VSC’s) should be as much of a concern for the winemaking process, as they are when it comes to choosing the bottle closure. Indeed, it could even be suggested these findings have far greater general implications for winemaking than they do for closure selection.
It was entirely unexpected for the subject of screw caps to have gone so deep. But the more one digs towards the roots of discussion, the deeper they keep on growing.
Whether or not European and Italian screw cap resistance is rooted in traditional protective behaviour, or whether it is born of traditional passivity or even if it’s partly or wholly attributable to the blind acceptance of a wasteful habit, the twists and turns for traditional minds are certain to endure. In reaching this point, I daresay the illustrious members of Gli Svitati have done the wine world a very valuable service.
To understand the nature of our resistance to anything and, if possible to appreciate the potential that change holds for us, I believe there is always one formative step that must be taken. And that is?
We must always… turn and face the strange.