Wine Seals – Far from Closure

This article first appeared in WBM, 2007
Tyson Stelzer

The closure discussion may have shown signs of subsiding in Australia, but it continues at full steam in our key export markets, and the implications are significant. Research which has emerged in recent months indicates that there is still much uncharted territory ahead.

The 2006 Global Wine Closures Report from wine business analysts Skalli & Rein represents a detailed overview of the international market. Of some 19.7 billion wine bottle closures worldwide, natural cork currently represents 13.1 billion and technical, colmated and agglomerated cork a further 2.9 billion. The report forecasts cork as maintaining its image in Old World countries, but if cork producers “do not react to the TCA crisis, screw caps will continue their impressive breakthrough until only Grand Crus remain with natural corks.”

The question should be not so much whether producers will react, but whether the results will be considered satisfactory. Amorim is presently in the process of implementing its ROSA Evolution method for reducing TCA in entire corks, although the reported results for theROSA method on granules only indicate a 70-80% reduction, and it remains to be seen whether similar levels can be achieved for whole corks. The question of what is an acceptable level is still open for discussion, although it seems that Oeneo has hit the mark with its DIAM products.

Synthetic closures claimed an annual market share of 2.5 billion units, which represents an annual growth rate of 20 percent for the past decade. The report questions whether such growth can be sustained. According to Stefano Alderuccio of Supreme CorqUK, “consumers want synthetic corks to seal the bottle perfectly, to prevent oxidation, to be easy to extract from the bottle and from the cork screw, and easy to reinsert.” The challenge for manufacturers is to achieve the perfect balance. As Richard Gibson of Scorpex Wine Services points out, “Polymers with an ideal combination of elasticity and oxygen exclusion at cost-effective prices are difficult to find.”

Screw cap market share has grown by 300 percent in the past three years, to now represent some 1.2 billion caps annually.Australia remains the largest screw cap market in the world, accounting for very close to one-third of this worldwide total.

The Skalli & Rein report urges that screw caps must improve their liner and convince consumers not to judge them as “cheap or downscale”. The question of screw cap liner is a contentious one, particularly in the light of the results of the faults clinic at the 2006 International Wine Challenge (IWC). Of the nearly 13 500 wines tasted, 7.2 percent were deemed faulty by the judges and about half of these were put down to closure-related problems.

Sam Harrop MW, who was responsible for running the faults clinic, reported that “in a number of cases the IWC chairmen validated a link between screw cap use and an unfavourable vegetal/rubber-flavoured compound – presumed to be a complexed sulphide.” 2.2% of all screw-capped wines were found to be affected, leading Harrop to suggest that “this fault type is significant and should be given more attention by wineries using screw caps.”

To put this figure in context, the cork taint rate from the same tasting came in at 2.8 percent, which is interesting in itself. Is all the hard work that the cork companies have been putting in starting to pay off? It appears that it is, according to South African wine judge David Hughes, who refers to cork taint figures of six, seven and eight percent as the norm at wine competitions around the world during the 1990s and now notes “a fairly dramatic reduction in those numbers” – but is quick to point out that the job is not yet complete.

Irrespective of such better-than-expected cork taint rates, Harpers magazine reported the 2.2% screw cap reduction rate as “alarming.” Personally, I’m surprised that it’s so low. In my travels around the globe I have been concerned to find that many winemakers remain uninformed regarding the procedures for reducing reductive characters, and I am encouraged that the implications of this are only reflected in 2.2% or screw-capped wines.

Harrop pointed out that countries which have been using screw caps for longer, such as New   Zealand, have much lower failure rates. “There’s still a lot of work to do to change winemaking techniques to suit this new type of closure,” he said.

And this applies inAustralia as well. A few months ago I tasted a recently released screw-capped Australian Riesling from the 2003 vintage which displayed disturbing levels of hydrogen sulphide. By comparison, the 2004 and 2005 vintages of the same wine were perfectly clean. The ensuing conversation with the winemaker revealed a comprehensive regime implemented since 2003 to successfully address the problem. The results are encouraging, but lead to concerning implications. The company in question was a very large producer which had been bottling wine under screw caps continuously since 1998. If it takes this long for one of the key pioneers to get it right, how much longer will this issue plague the wine world?

The Australian Wine Research Institute (AWRI) has been developing and actively disseminating strategies for avoiding this problem for more than five years. Managing director Professor Sakkie Pretorius refers to the AWRI’s “demonstrably successful work in helping winemakers to avoid the potential problem of what we call ‘post-bottling reduction’”.

He is also quick to refute the notion that there is a high incidence of post-bottling reduction in wines sealed with screw caps. Three successive AWRI Advanced Wine Assessment Courses have indicated a higher incidence of reduction in wines sealed with cork compared to wines sealed with screw caps.

Some commentators take a different approach. Scientist and author Dr Jamie Goode suggests that “complications like this mercaptan issue should put pressure on winemakers to be more curious about the closures they are using. They should ask more questions about issues like oxygen transmission.”

I am not convinced that this is simply an oxygen transmission or a screw cap liner issue. The key priorities for winemakers are to remain more diligent than ever in managing reductive characters, regardless of the closure, and to support other makers in this by sharing their knowledge and experience. The International Screw Cap Initiative is a non-profit organisation established to assist with this process (www.screwcapinitiative.com).

Corks, synthetics and screw caps remain the focus of the packaging discussion, but the Skalli & Rein report points out that Bag-in-Box represents the fastest growing packaging segment globally in the past decade, now accounting for close to 30 percent of all wine sold in theUSand nearly 50 percent inAustraliaby volume. This segment could grow further if it is embraced by the ever-growing on-premise by-the-glass programmes.

Glass closures are beginning to gain commercial acceptance, particularly inGermanyandAustralia, but have been called into question on the basis of whether the ethylene vinyl acetate “O ring” that seals the cap to the bottle is reliable for long-term wine ageing. The report also mentions alternative closures such as Canned Wine, Tetra Brik Wine and ZORK, designed to attract the attention of the consumer, but notes that they still represent small niches, and more research is required in determining their oxygen transmission levels.

In looking to the future of wine closures in 2007, TheUKDrinks Business Trend Report 06/07 highlights “convenience” as one of the buzz words. This takes on a number of dimensions: the package must be the right size and it must be fast and easy to transport, open, consume and reseal. Portion control through smaller or resealable packages is tipped as driving sales, through innovations such as Tetra Prisma packs.

Marc Engel of US marketing research firm B/R/S says that “there is now room for everything on the market.” US consumers are ready to buy bottles of different sizes with different closures. Alternative size packages are showing growing acceptance, with huge potential for further growth predicted. Negative consumer sentiment regarding screw caps has dropped and “there is a huge potential for screw caps.” One of the hold-ups in theUSmarket is that wineries are taking a “wait and see” approach to screw caps but consumers will only accept them when they see more of them on the shelves. The situation is beginning to turn around as more and more wineries bottle premium wines under screw cap.

In the coming year we can look forward to seeing results released from new trials measuring oxygen ingress through various closures, the performance of different screw cap liners and more up-to-date data on alternative closures. Regardless of what these reveal, it remains certain that the discussion of wine seals is far from reaching closure.