Wine Closure Systems and the Environment


Cork vs. Screw cap: A fight over the environment” is the title of a recent article in the Seattle Times. The title being what it is, I thought it would be a push towards screw cap usage to better the environment – I was surprised to read that I was wrong.

Apparently, cork farming is good for the environment on an ecological as well as a socioeconomic level. Cork trees take up 6.7 million acres of land in the Mediterranean regions where they thrive, and cork is a sustainable product that promotes healthy growth of the tree over its approximate 200 year life span.

Here is a quick primer on how cork is harvested (from After about 25 years of the tree´s life, cork used for wine can be harvested. It is after this period, the tree is considered mature and the cork is cut in the form of strips. These strips are then carefully removed and dried for 6 months or so, after which they are boiled for a few hours and then left to dry for around 3 weeks. Subsequently, they are cut and/or molded into the correct cork size. The cork trees can be restripped every 8-14 years throughout its lifespan.

Next, the washing process occurs where a variety of chemicals are used to sanitize the corks against bacterial growth. Some manufacturers are utilizing new technologies such as irradiation as a weapon against the potential bacteria growth, which results in cork taint. Corks are then sealed in bags containing inert preservation gases before being shipped to wineries.

Since the trees are not killed during harvest, it is considered a sustainable resource. The article points out that, as screw cap usage goes up, cork farms will begin to be neglected and will eventually die. Since the majority of cork forests are privately owned, the decline of business for farmers could lead a sell-off of land and subsequent industrial and commercial development. Obviously the ecosystem would be terribly disrupted, in addition to the sociological impacts of 100,000+ people losing their jobs, which could also be devastating to the economy.

So why do winemakers use screw cap closure systems if the use of them threatens cork tree existence? Well it is mostly an issue of quality. Cork is a pretty awesome closure system but it can have its bad days. The biggest reason for use alternative closures whether it be screw caps or synthetic corks is the removal of the possibility that the wine will get cork taint, chemically speaking TCA (2,4,6 Trichloroanisole). TCA will give the wine that famous musty, wet cardboard smell that affects an estimated 5% of all bottles sold. Also, screw caps aren’t susceptible to drying out and letting in air that can oxidize and ruin the wine, or just become brittle and break apart as someone is trying to open there bottle for dinner. So if your brain is anything like mine, you are thinking – well at least screw caps are recyclable? According to the article they are not. The typical process involves non renewable resources and a plastic insert that make it difficult to reuse and not acceptable to most residential recycling programs.

So my question to help settle the debate would be to ask, which manufacturing process is better for the environment? Does one process have less of an environmental impact than the other? Unfortunately I do not know the process of making screw caps nor do I know how much energy and/or waste is produced in the process for cork making outlined above. And at the winery level, which is most efficient on the people power as well as which method has the smallest carbon footprint? The question above is purely to settle the environmental/ecological side of the debate. There is no real way to account for the loss of 100,000 jobs unless you build screw cap mfg. facilities on the sites of old cork farms.

Obviously their are other debates out there on cork vs. screw cap like: screw caps take away the romance of opening the bottle, and only cheap bottles have screw caps. Well the second is definitely not true anymore as bottles over $100 are starting to show up on wine store shelves with brand new screw caps.

So what does everyone think? Give me a shout with your opinion on the subject.

Categories: wine, wine education, wine industry issues | 4 Comments

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4 thoughts on “Wine Closure Systems and the Environment

  1. pjpink

    As far as one being more environmentally sound over the other, I do not have a clue. But my husband and I ran across a wine last week that gave us second thougths about screw caps. It was a 2005 Two Angels Petite Sirah from High Valley in California. This was no cheap wine and it had a screw cap. Upon opening, the wine needed decanting something fierce. Very tight and tannic. If it had been sealed with a cork we would have waited a couple of years to imbibe, but with a screw cap would it make a difference? Will a wine age with a screw cap?

  2. John Witherspoon

    Hey PJ,
    Thanks for writing!
    Okay so I totally have/had the school of thought that you do on the no age ability with a screw cap. I mean come on, a wine needs the minute amount of oxygen over time to soften up those tannins and make the wine what it is right?!?!?
    Well over the past 6 months or so I have asked around and done some tastings with older vintages that had screw caps and bottles can in fact age with one. Although I DO THINK IT is a much slower process, and I am not sure if I am really a believer.
    Here is a link to a study that Hogue Cellars did over 5 years with all different types of closures and the screw cap wine came out on top.
    I hope that helped – but honestly like I said I am still on the fence, and if I had to have a wine that needed to be laid down for a few years – my current thoughts would want me to have a cork.
    Thanks PJ


  3. Chris

    This is very interesting. I would have assumed that the screw caps would be better environmentally, but I did not realize that cork was a sustainable resource.

    Personally, I am sold on screw caps being the better enclosure, but I think that environmental implications should not be ignored, especially since it is a agricultural industry at heart. I would be curious to hear a counterargument to this article (if there is one) and make up my mind then. Thank you very much for posting on this. I will definitely reference your post in my blog.

  4. Ambivalent Richmonder

    I first came across this issue while living in Vancouver, Canada. The local wine board, VQA, certified wines to ensure quality of BC wines. However, they refused to certify any wines with screw caps as they believed it was an inferior sealing mechanism.

    One winery was fighting that ruling with arguments about the environmental superiority of screw caps as well as data for its alleged equality of quality. Unfortunately I can’t find any articles about this debate (which was about 5 years ago)- but the anti-cork winery made some great points (with data) about why screw caps were better.

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