Categorized | Technology

Seeking Closure: Screw Caps vs. Corks Technical Tasting

I’m reminded every day that the appreciation and enjoyment of wine is a very personal experience. What you like may not be the cat’s meow for someone else. This was evident at the ’10 Oregon Wine Industry Symposium (OWIS), “Technical Tasting: Seeking Closure & Hi-Tech Winemaking“.

Most of the attendees were winemakers, viticulturists and industry folks in the know when it comes to high-tech stuff like RO, ultra-filtration or VA (don’t worry, we’ll get to these wine geek terms in a later post) but what blew me away at this event were all the differences in opinions between the wines we tasted.

There were a few hundred industry folks locked in a room (well, not literally) for a couple of hours to taste and discuss closures and Hi-Tech Winemaking. Harry Peterson-Nedry from Chehalem Winery moderated the session with panelists Domingo Rodriguez (Winesecrets), Clark Smith (Vinovation) and David Paige (Adelsheim Vineyard).

We kicked off the technical tasting with a comparison between cork and screw cap closures, blind tasting two white wines – identical in every way except one was bottled using cork, and the other under screw cap.  So what’s the verdict?

Harry asked us to taste both samples and identify which one we preferred. This was exciting stuff since it’s not like we get to experiment with this sort of comparison every day. Seriously, can anyone really have a strong opinion on cork vs. screw cap without a trial that compares apples to apples?

I thought it was best to go in with an open mind and try not to guess which wine was under cork or screw cap. I simply tasted the wines and selected the one I liked best.

Wine #2 had more pronounced aromas and flavors. The aromas were bright and the flavors seemed to instill a more vivacious appeal than the first wine. As everyone scribbled notes and marked their papers for preferences, Harry announced we were drinking barrel-fermented chardonnay. “With a show of hands, how many of you preferred the first wine? What about the second wine?” The verdict seemed to be split down the middle.

So which wine was which? Wine #2 happened to be the one under screw cap. Was I surprised? Not really, but this did, in my opinion, debunk the theory that cork screw liners inhibit oxygen transmission into the bottle, which [if you haven't heard] causes reductions of aromas and flavors. Interesting indeed.

Clark actually agreed with my choice but reneged his decision, “… I certainly preferred the second wine (screw cap) but now knowing that it’s a chardonnay, I’m not sure I would take that same view“.

We also tasted two identical ’03s and two ’04 Pinot noirs under cork and screw cap. To some extent, I preferred the cork closure in the ’03 but the distinction between the ’04s were extremely difficult to ascertain, which brings me to the Plumpjack story.

Back in ’97, the vintner embarked on an experiment and bottled half of their premium $160 Cabernet Sauvignon with cork screw closures. Before this time, vintners only used screw cap closures for inexpensive white wines.

In ’07 (ten years later), PlumpJack invited friends and wine writers to compare and contrast the ’97 screw cap and cork bottles side-by-side. Amazingly, most could not tell the difference between the two.

I immediately thought about the Plumpjack story when Harry announced what we were drinking. I know this was a small trial, but the evidence seemed to show that the longer the wine was cellared, the more difficult it was to differentiate which wine was under cork and which wine was under screw cap. Gotta love this stuff.

Personally, my take on the OWIS trial is that screw caps seemed to show well for young white wines and reds with 8+ years cellaring time. Red wines that are drinkable upon release (with shorter cellar times) might be better suited for cork.

Harry went on to say that, “We’ll have to track these [trials] over time, we’re just taking a snapshot right now, and we don’t have a lot of material available to us from trials“.

Domingo went on to say, “we may have to adapt some of our winemaking before we use alternative wine closures“.  I’m not sure if I agree with this statement. If I were a winemaker, I wouldn’t tolerate wine closures dictating how I make my wine, but that’s just me.

It would be interesting to repeat this technical tasting by throwing in a few [younger and older] red wine samples and other closures such as Vino-Seal or synthetic (heck, for kicks, lets throw in tetra-pak as suggested from my twitter friends @NWTotemCellars and @nectarwine)!

So winemakers and enophiles, what’s your preference, cork or screw cap? Why? Hit me up with your comments. I’m listening.

Next up, we’ll taste a flight of four Lodi Syrah’s and give you the findings of an astringency test. Geek alert! Woot! Woot!

~Pamela Heiligenthal

This post was written by:

- who has written 298 posts on Enobytes Wine Online.

Editor and co-founder of Enobytes.com, Pamela is a former restaurant manager, wine buyer, and sommelier with WSET, CMS & Center for Wine Origins certification. She has contributed to or been quoted by various publications, including the Los Angeles Times, Sommelier Journal, Vegetarian Times, VIV Magazine, UC-Berkeley Astrobiology News, The Washington Post, the Associated Press, and USA Today. True to her roots, she seeks varietal and appellation integrity and is always passionate about finding the next great bottle of wine.

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25 Responses to “Seeking Closure: Screw Caps vs. Corks Technical Tasting”

  1. Per-BKWine says:

    Very interesting post! There are just too many people who say “of course X” is better (X being cork or screw cap, depending on the commentator).

    I’m not sure I follow you when you think it is outrageous to adapt wine making as a function of what closure is used. (Or perhaps I think you are over-reacting.) All techniques and technologies impact the result and can thus give a reason to adapt winemaking. There is really no such thing as a “true” or “pure” or “unadulterated” wine. The winemaker just have to take all things into account and adapt accordingly.

  2. Great article. I’m currently half way through the fascinating “To Cork or Not to Cork” tome by George Taber – great read by the way. Given that the “verdict” summarized above did not clearly side for screw or cork – I’m curious as to what specific result Domingo was basing the assessment for adaptation of winemaking on? Note, that he is not alone in such statements, many of the same sentiments are relayed in Taber’s book. I’m just curious as to what, objective, “cork v screw” result winemakers are basing such statements on. Thanks !

  3. Cato says:

    I sat next to a woman from New Zealand last week during a wine and food pairing. She wanted to know why we in the States has not adopted screw caps. I had no answer. It sounds like the wine industry in NZ has convinced consumers that a screw cap was superior to corks.

  4. enobytes says:

    Per-BKWine, awesome comment, and yes, maybe I’m over-reacting. When it comes to “winemaker intention” I get it. They are in a position to integrate closure design into the winemaking process based on what they are trying to achieve. I should have added more context in my post above to clarify. The discussion focused on Pinot and some stated that if we wanted to utilize screw caps for younger wines, we would have to make it taste better. I agreed with many (colleagues and panelists) that the younger Pinot did better under cork. But here is my point – if a cork closure makes readily drinkable wines taste better, why use screw cap? Would anyone ever force a winemaker to use a closure which might not showcase the wine at its best? Sure, the winemaker could adapt processes to accommodate alternative closures, but what is the reasoning? Costs? Cork taint? Are you willing to give up flavor to save $ or reduce cork taint? Both are logical reasons for the deviation, but if I were I winemaker, I wouldn’t want someone else (e.g. an owner, accountant, marketing person, etc.) making those decisions for me. This is a winemakers decision. I’m curious if this sort of scenario happens often?

  5. enobytes says:

    Hey Keith, I’ve been meaning to read the book you mentioned – haven’t yet and it sounds like a good read. Domingo was addressing a tasting he had recently with a young Pinot under screw cap and he noticed a bit of spritz to it, questioning if the spritz would dissipate with longer cellaring. Harry summed up his comments by stating that using different closures might require adapting some of our winemaking before it goes into the bottle. Which goes back to my original question – do we really need to adapt or simply use a closure that works for the intended purpose. This is sort of a weird analogy, but I sort of look at it like this – don’t use a jackhammer if a simple hammer would work.

  6. enobytes says:

    Cato, interesting indeed!

  7. My husband is the winemaker for Keswick Vineyards and he always says screw caps are better for the wine- no risk of the wine getting corked or the cork drying out and the wine getting oxidized. That being said, we still aren’t using screw caps at our winery because many customers still prefer to uncork a bottle of wine, seems more special than twisting off a cap, and many people still assume wines with a screw cap are inferior wines. We compromise by using a technical diam cork, which is guaranteed to be TCA free.
    If we did start using screw caps, it would initially only be for wines that were meant to drink right away like our Verdejo I think. He doesn’t feel there is enough data out there yet to compare how wines age with corks versus screw caps to try them on our wines that are meant to be cellared.
    Interesting to taste them side by side like that though!

  8. enobytes says:

    Thomas Houseman posted a great comment on my facebook page for which I wanted to share:

    “Great that you are sharing this tasting. As a winemaker, I disagree with your comment about letting closures dictate your winemaking. I have switched all our wines to Stelvin closures, and in doing so dropped SO2 levels in our finished wines drastically. Why? Because the oxygen transfer rates are much higher in cork-finished bottles. There is no… See More need for the extra sulfur, which is great for those who are sensitive to SO2. Secondly, I make sure the wines going in to the bottles get their share of O2 before bottling. It is their last gulp of air for a very long time. These are little changes, but as a winemaker I have to be as mindful of the closure as anything else. It is a factor that can’t be ignored. It will never change my overall philosophy of natural winemaking, but it would be remiss of me not to consider the closure. It’s my job.”

  9. enobytes says:

    Kat, I think your concerns are shared by many. Thanks for the comment.

  10. Pablo Orio says:

    Hi everybody, I am trying to write in English although it not my mother tongue because I am Spaniard. I am winemaker and R&D Manager in Bodegas Riojanas (Rioja, Spain). I am sure that this post is very interesting; in my opinion crew cup is the best close for younger wines especially white wines for aged wines I am sure that is better natural cork because there is a little oxygenation into the bottle.
    There is a interesting study: CONJOINT RESEARCH FOR CONSUMER PERCEPTION OF WINE CLOSURE OPTIONS AND THEIR IMPACT ON PURCHASE INTEREST IN THE UNITED STATES AND AUSTRALIA
    If someone wants it I send him by email.
    I apologize for my English.
    Hugs from Rioja, Spain.

  11. I have perhaps been a bit shrill on the subject, and for that I must apologize. It has been pointed out to me, correctly I might add, that there are other factors above and beyond wine quality that one would well consider in making a choice between cork and screwcap. (For purposes of this discussion, I will utterly dismiss synthetic closures as being beyond the pale for any number of reasons.) But one should well consider the cultural and environmental issues that may well be invisible to us, but have an impact nonetheless. While tin screwcaps are thoroughly recyclable, as a practical matter, they generally are not. I have personally been remiss in not being more active in seeking a practical solution to this problem. (Frankly, I’ve been rather too busy trying to keep my own head above water to focus on this as much as I should.) The production of cork does in fact support cork forests and there is as well a cultural patrimony that these forests support.

    There is some degree of evidence that the phenomenon of corkiness is not as prevalent as it has been and that cork manufacturers have solved some of their technical problems. Maybe I have just grown too jaundiced in my attitude, as I have heard talk of “solutions” for the issue of corkiness for the last twenty years and the solutions have never been quite as definitive as advertised.

    Allow me to apologize again for my sometime inflammatory rhetoric vis-a-vis the cork. Old habits die hard.

    But I do love screwcaps, at least from a technical standpoint, and I especially love how they support the integrity of the wine. As has been pointed out, they are a more oxygen exclusionary closure, and therefore one is not obliged to use as much SO2 to obtain an equivalent level of microbial and antioxidative protection. This is a very beautiful thing. Because there is less oxygen ingress, the wines develop more slowly and are capable of longer life (50% longer I would reckon, as compared to a cork); this is also a very beautiful thing for a vin de garde.

    I won’t even address the problem of consumer preference for the ceremony of the ritual of the opening of the cork. For those who insist on this antiquated ritual, I can only tell them to just get over it.

    The issue of post-bottling “reduction” is a real one, and there is no question that many wines, especially reds with a degree of anti-oxidative life-force (rich in minerals, tannins and anthocyanins) are particularly vulnerable to this phenomenon, though there are a few things that can be done to mitigate this contretemps. This genre of wine will typically exhibit a degree of mild retardation for anywhere from months to a few years before coming out of their funk. Yeah, it can be a problem if you are absolutely bound to release a wine within certain calendar constraints. But, as perverse as this might be, I am now coming to believe that the presence of this post-bottling issue, assuming that it is just a relatively mild case, actually bodes incredibly well for the ultimate evolution of the wine. There are many winemakers in Europe who hold to the wisdom of allowing their wine to pass through a reductive phase during the first winter after vintage; this is done for any number of reasons, but seems to lay the foundation for the evolution of more interesting flavor elements as the wine develops. The post-bottling “reduction,” if it is just a mild case, seems to me to be a sort of recapitulation or faint echo of the cellar
    “reduction.” But after the wine passes through this phase, there is a kind of soulfulness, a depth, earthiness, if you will, that I can only equate with a different kind of reduction that occurs when you cook. Slowly braised dishes have a depth and a complexity that find that I just adore, and there is something like this that occurs with screwcaps.

    I would even go far to say that anything a winemaker can do to slow down the evolution of his/her wine will ultimately redound to the wine’s greatness.

    the integrity of the wine.

  12. Per-BKWine says:

    One of the particularly interesting things in the original post was that the conclusion (in that experiment) seemed to be that screw cap was more interesting for wines to age – which is the opposite to what is often thought. (E.g. as Pablo says in the previous post.)

    Another question that is interesting is (and not much debated): can one reduce this debate to the simple question of oxygen transfer through the closure or not? Or is it not as simple as that?

    A screw cap is not 100% “air tight” (=0 transfer rate).

    Various studies have also shown that there is indeed a certain oxygen transfer through natural cork.

    A screw cap can actually be designed with different transfer rates, e.g. very tight or with a transfer rate similar to natural cork. (There’s a short article by Jamie Goodie on that in a recent Drinks International)

    But the only real test of what is appropriate or not is to do much more extensive testing over long periods of time, comparing identical samples of wine. And I have heard of very few of those.

    And the answer will probably be – there is not one single BEST closure. It depends on what you want to achieve.

    PABLO – Yes, I would be very interested in the report you mention. You can send it to info@ with the ending @bkwine.com. Thanks.

  13. enobytes says:

    Per-BKWine, thanks for the additional comments. I agree with you 100% that there is no single BEST closure. It depends on what the winemaker wants to achieve.

  14. enobytes says:

    Pablo, thank you very much for the insight and information!

  15. enobytes says:

    Randall, thanks for the excellent response. Cultural and environmental issues are extremely important and unfortunately, this panel didn’t get into a discussion about this topic. There are impacts that need to be addressed. I find you’re “slow braised” analogy enlightening. I haven’t thought about it in this fashion but it makes sense.

  16. Bradski says:

    Corks seem to be taking the “green’ road lately with an emphasis on their ability to make less of an environmental impact than screwtops or extruded plastic.
    I use whatever I can afford. Can’t do screwcap (would like to for all our whites) because I can’t buy the machine or afford the mobile bottling guy. My consumers tell me plastic is fakey and cheap although from a functionality perspective they’ve always been good to us.Our consumers also tell us they think cork is a sign of a ‘serious’ wine.

  17. Shaun Richardson says:

    As (former) winemaker with Clos Pegase Winery in Calistoga, I have seven vintages of screwcaps under my belt and had the luxury of performing these types of tastings regularly.

    In January this year, with 22 North CA wine sales reps (generally considered to have very good to excellent palates), I poured a 2004 Chardonnay, blind, under both Stelvin and Cork. (We had bottled both in commercial quantities). Opinion was split 11-11, and the agreement was ‘the wines were different styles’

    Also in January this year, to the same group, I poured a 2003 Pinot Noir. Opinions were 20-2 in favor of the Stelvin. The cork finish wine was ‘tired and old’.

    Lastly, during 2007 I had the luxury (hah!) of tasting some 60 bottles rejected from our Visitors Center as being ‘faulty’. During the period, we had opened some 2,000 bottles of wine, 2/3 cork finish, 1/3 Stelvin. NONE of the Stelvin wines were faulty. 1% of the cork finish wines were ‘corked’ (as in, very obviously musty), and a further 3.6% were rejected with descriptors ranging from ‘flat’ ‘tired’ ‘oxidized’ etc

    What can I say, I am convinced, and would happily bottle everything that way!

  18. Last week, I tasted a 2007 Sauvignon Blanc and a 2006 Cabernet Franc from Paumanok Vineyards, one of the best estates on Long Island. Both had been bottles in cork and in screwcap, as part of an ongoing experiment on closures. Paumanok bottles a fair deal of their whites and more accessible reds under screwcaps, but reserve wines are still mostly under cork.

    There was something a little brighter, a little more expansive to the wines under screwcap. The difference was relatively modest, however, and more discernable in the white than in the red.

    I’m guessing that the presence of tannins and more solids in the reds may make the strictly aromatic components less decisive in the tasting impression. Put another way, what you smell may be more what you taste in whites than in reds.

    I would tend to say that bottling young-drinking whites and light reds under screwcap makes perfect sense. As for long-aging reds, I’m not so sure. Yes, the wines may evolve a little faster under cork, but sometimes, I’d be happy to taste them at maturity, a little sooner, rather than when I’m old and my tastebuds start to fail me. It all depends what you’re looking for.

    The environmental issues are also something to be thought about carefully. Recyclable and recycled are two different concepts. I would be tempted to say that there is often a high failure rate between the two.

    I also think that treated cork closures like DIAM should be given a careful look. Hugel, in Alsace, carefully studied its effects and has adopted it with empirically-supported enthusiasm.

    In other words, I don’t think there is an absolute answer to this. And I do think that cork failure rates have probably dropped – and were probably overestimated, anyway. But Randall, don’t be so hard on yourself: if people like you hadn’t shouted their discontent at natural cork, cork producers wouldn’t have been driven to improve their products over the last few years.

  19. enobytes says:

    Shaun, your experiences seem to mirror some of my personal experiences as well as the trial. Thanks for sharing – great stuff! ~Pamela

  20. enobytes says:

    Rémy, thanks for your comments. I agree with you that wines under screwcap seem to instill a little more brightness – and you make a good point about the longetivity of screwcap reds.

    Your comment about overestimated cork failures peaked my interest. Years ago, I was working as a Sommelier at a San Francisco restaurant and I had a huge problem with corked wines. I had a few favorite producers I had to drop from my list because I had (on an average) three corked wines per case. Seriously, it sucked big dogs. Things have improved immensely in recent years but for a while, it was pretty rough.

  21. Paul Kalemkiarian says:

    Interesting article. This has certainly been a hot topic as of late. We over here at Wine of the Month Club actually had a very nice woman call in the other day and cancel her membership because she had received a screw cap wine. I would venture to guess that 40% of the wines that I taste each month are sealed with a screw-cap. Unfortunately, and particularly in the US, people do associate screw caps with dollar-a-gallon wines, and there seems to still be a lot of resistance to the cork-screw cap switch offered up on the part of the consumers, despite the fact that many high-end wineries are moving towards this type of closure. Just the other day I interviewed a winemaker from Australia, and Australia seems to have much more readily embraced this change in technology.

    That said, I realize that there is some romance ascribed to extracting a cork, and for many the act of uncorking is as as integral and sacred to the wine-tasting experience as the drinking of the wine itself.

    Here’s a video I filmed about the topic back in 2007:

    http://vimeo.com/9589462

  22. Winfred says:

    I can’t believe folks are still debating this topic :)

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