[question] Question submitted by Cameron Parrent: One of the few criticisms of screw caps is that their seal is too good and wine will take longer to develop. On average, how much longer do you think a wine in a screw cap will need to be cellared? And can you see other forms of closures, such as the zork, becoming widely used, or have screw caps been too widely accepted? [/question] [answer] Screwcaps have undoubtedly become the immediate choice for winemakers opting away from cork. Most winemakers move away from cork for one of several reasons: they have tired from what they believe are excessive levels of spoilage from cork taint, they have tired from what they believe are excessive levels of ruination of their wines from sporadic (random) oxidation, the process by which air enters the wine either around or through the cork, or else they have tired from what they believe to be years of the cork avoiding the central issues of technical quality. There is a very widespread view that had the cork industry spent as much time and effort on quality control throughout the last decade as it has on public relations, that a significantly higher number of wine producers would still be using cork. Either way, for better or for worse, the cat is out of the bag, and the cork industry is now playing catch-up. Whether or not screwcaps are too widely accepted is another issue. When correctly applied, screwcaps deliver a perfect seal. They reflect whatever is in the wine, good or bad. It now appears that cork has some inherent property, which might relate to porosity and might relate to selective absorption, that enables it to better protect (given its accepted inadequacies with respect to cork taint and sporadic oxidation) wines that are bottled with high levels of bound sulphides. There are now many instances of wines, even from unoaked styles like riesling and sauvignon blanc, that have suffered because they were sealed under a screwcap without having first been properly cleaned up in the cellar. The bound sulphide characters not uncommonly seen in these wines, which amongst other things can resemble rubber, asparagus and sweet corn, are avoided by winemakers who are more acutely aware of the very particular requirements associated with bottling wine under a perfect seal. What then, about the more reductive expressions of white wine, such as very traditionally made sur-lie chardonnay, and even sparkling wine? Personally, I believe there is a significant risk associated with sealing a heavily reduced chardonnay, aka Giaconda or Kumeu River, with a screwcap, since not only is there a healthy chance of the exacerbation of their inherent reductive complexity beyond pleasing and balanced levels, but as Kooyong’s Sandro Mosele points out, there is a chance of the palate flattening out and never really developing the richness and substance expected of the wine. This ‘flattening’ effect ideally suits wines like riesling and sauvignon blanc, for it enhances their raciness and tightness. But it’s also the very last thing you want in a more substantial white Burgundy style. Also, when you think about it, possibly the last thing you might want in a creamy, round and generous sparkling wine. Although this is slightly off the topic, Hardy’s sparkling winemaker Ed Carr took issue with me over an article I wrote recently about crown seals for sparkling wines. His stance, which he says is based on years of tasting trials, is that crown seals have a similar flattening effect on his premier Arras sparkling wine. I have accepted an invitation to taste these trials in the near future, and will report back. However, from a point of view of logic, his argument has substance. New Zealand-based trials on various sauvignon blancs under different seals suggested that the differences between cork and screwcap had more to do with the absorption of reductive elements by the cork than the actual porosity of the cork seal with respect to oxygen. This is not a universally accepted view, since many winemakers believe that to avoid the excessive build-up of reductive influence under a screwcap, certain wines, ie traditional white Burgundy styles, require some measure of porosity in their seal. This is the reason that a steadily increasing number of winemakers are using Diam, a synthetic cork-based seal built into a totally inert matrix that facilitates a very small measure of porosity. Treated to remove all traces of cork taint, the Diam seal is championed in Australia by Sandro Mosele who, after a very detailed investigation for a seal to suit his own wines (which do carry levels of reductive complexity), selected it. Time will ultimately clarify all these issues, but for the moment I can see the sense behind Diam. On that basis, I expect that winemakers to choose seals for their wines in future that deliver a particular level of porosity considered ideal for whatever style of wine is in question. They are likely to want to dial up more porosity for a complex oak-matured chardonnay than for a tight, austere riesling that would perhaps demand no porosity at all. Today, the makers of screwcap seals are working feverishly to perfect screwcaps with consistently accurate levels of porosity to meet this very demand. I would therefore expect other types of seal, which do not yet provide this level of flexibility and customization, not to last into the future. The more we discover about this field, the more options that will become available to winemakers, the more demanding they will naturally become. As for the question of how much longer a wine in a screwcap needs to be cellared above and beyond the same wine sealed under cork; it’s almost an impossible question to answer meaningfully. Yes, they should last longer, especially since the risks of cork-derived spoilage or oxidation are removed. Their development towards maturity should be slower, but given the huge number of variables associated with why this might occur, it’s not possible to generalise over. The point is that under a totally inert seal, wines mature in a different way. While they should take longer to peak, how they look like when they get there will be something totally new to most of us. It’s then up to us all to re-evaluate everything we thought we knew. It’s that much of a change! [/answer]
