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March (No. 494)


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Screw cap pioneer poses questions

Jo Jalfon , New Zealand correspondent

Jeff Grosset, a pioneer of screw cap closures among Australia’s Clare Valley wine community, shared his insights of closing wine under screw caps with delegates at the recent First International Screwcap Symposium.

He began by telling delegates that the reason screw caps had been so successful was because “they don’t taint or cause random oxidation”.

“The other reason is screw caps fitted with the liners most commonly used on premium wine, ie. Saran Tin, have very low permeability, meaning tiny amounts of air are introduced. However, the permeability of a screw cap can in fact, be varied almost infinitely and, certainly in Australia, we now know how to do this commercially.

“The problem is we don’t know what amount of air, if any, is beneficial and this is one of the reasons I established the Australian Closure Fund. So, with so many now embracing screw caps we should ask ourselves; are screw caps the answer? If so, to what?”

Grosset highlighted the recent shift in focus from wine quality to wine closures, particularly in the media. He also discussed the current understanding, perception, technical problems and criticisms of screw cap closures.

“Screw caps have become the new standard by which any new wine closure (or improved old closure) will be judged. If, for example, it is confirmed that cork taint can now be removed I will welcome this news although that still leaves the issue of cork’s variable permeability. If for example a glass closure is announced tomorrow that is commercially viable I would be happier because it would deal with variable permeability but it would raise the question of the appropriateness of zero permeability.”

Grosset continued to discuss wine issues that have been associated with screw caps including reduced characters.

“In the case of reduced characters I think we should go further than just discussing this at the conference. At a recent NSW Wine Press Club lecture, we staged a mock trial.
“We turned around the argument: Why use screwcap? And charged the custodian of Chateau Lafite with reckless endangerment of his brand, due to the replacement of glass stoppers, which amazingly Lafite used until the 1820s, with cork. Similarly, we could put screw cap on trial for crimes against wines such as causing reduced characters. We could appoint a well known writer on this subject to act as prosecutor.
“Someone like New Zealand-based wine writer Paul White, whose recent writings I describe as ‘screw cap fiction’ would be perfect! This would expose all parties to an environment where claims must be supported by evidence. I firmly believe that, unlike cork, screw caps haven’t helped those winemakers who may be considered either slightly guilty of sloppy winemaking or of producing funky wines, for those who like to distinguish between the two.

“But to accuse screw caps of causing the problem is another story. Yet, even though screw caps may not be the actual cause of reductive characters there is no question, according to some winemakers, that the screw cap is the offending party, and a guilty verdict would certainly let them off the hook.

“While we’re on the subject we should question why certain changes to winemaking procedures are being practiced, even recommended by consultants allegedly due to the closure. These include micro oxidation, changes in erythorbic and ascorbic acid use, dissolved oxygen and CO2 levels at bottling, copper additions and sulphur dioxide levels.

“On this subject I would be happy to act as prosecutor, and request evidence, not that these changes are warranted, but that they are warranted due to the closure. The exception is SO2 where it is clear that less SO2 is lost under screw cap compared with the average cork and therefore less SO2 at bottling is now appropriate, assuming that the producer was using sufficient SO2 in the first place, which was in fact often not the case in Australia.”

In closing Grosset claimed the introduction of screw caps had been the “most significant development the wine industry has seen in recent times”.

“The major issue has been the elimination of taint and random oxidisation, a massive leap forward in quality and consistency. The success of screw cap this time around is due in part to getting the important issues like fill height correct from the start. Permeability on the other hand is a work in progress. Is there an ideal permeability? And will it be the same for all producers and all wines? Is it a case that the closure should be adapted for some, or that some must adapt to the closure? On promotion, my experience is that common sense works. Tell your customers why you’ve changed and their understanding and trust will result in support.

“Let’s hope that our better understanding of the closure and the role it plays through events like this conference will result in all of us achieving more focus on passion, excellence, wine quality and the joy of wine. In fact, I’m looking forward to reading in the near future that the term “great bottle” which we know to be short for “no such thing as great wine just great bottles” will be referred to in the history books as used during a brief 350-year period of human history that coincided with the practice of sealing wine bottles with wads of bark. It should go on to say the widespread adoption of inert closures, screw caps being the most common in the early 21st century, brought about the redundancy of the term “great bottle”. Wines of such quality are now simply referred to as “great wine.”

Grapegrower & Winemaker

AB Mauri



WID 2017