The important thing is not to stop questioning. Curiosity has its own reason for existing. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery every day. Never lose a holy curiosity.

Albert Einstein

I am only passionately curiousWhen I asked myself if it was true that screwcaps completely protected wine from taint when I held still yet another glass of tainted wine from a screwcap-closed bottle, I had no reason to think that this would end up being a major research project.  I thought I could find the answers pretty quickly and could write a nice little post. Just like everybody else.  But as I looked further, the next answer would lead to still yet another question which left me even more curious as to the why.  Honestly, the only reason I stopped is because I realized that I could easily make this into a 20-part, book-length dissertation, and that is way more than I was prepared to do in this little blog.  There is a lot of information out there that I simply cannot publish here because my posts would be even longer and more numerous than they already are!  So if you contact me and tell me that I missed something, well, I know that. I missed a lot. Or, more accurately, there’s a lot that I chose not to focus on in this discussion.

The bibliography below is far more extensive but much less organized than I had planned.  In fact, I’m pretty sure that not every page, paper, article, or abstract I touched is listed here. Many of the resources were accessed early on before I realized that I needed to keep track of everything that I was reading and make sure that my citations were at least noted.  The bibliography is not organized in one of the recommended scholarly styles, but at the same time, I tried not to make it overly random or desultory. It coordinates well with the links that are scattered throughout the series. I think that you may agree that this series is at least as well researched as any other article that you’ll find on the subject.

Patrick Spencer of Cork Forest Conservation Alliance was an incredible resource, and he doesn’t get nearly the credit that he deserves.  I contacted several organizations early on and heard immediately from this one.  I never did hear from the screwcap folks – I think my email was probably lost because I can’t imagine that they wouldn’t have wanted to give me their side of the ongoing dialogue. Mr. Spencer answered my inquiries immediately, and he set me on the path of knowledge about this controversy. Even with his advice and guidance, I found many videos, read many blogs and web sites, read more scholarly articles than I have since being in school, read industry journals and many articles totally unrelated to wine, completely on my own. I also read quite a lot of the information on the screwcap and synthetic sites and papers supporting their use because I wanted to be as even-handed as possible during the research process. I did not want to go into this project having a mindset of verifying a predetermined conclusion and then researching to support that conclusion.

Through all of that, there were a couple of statements that Mr. Spencer sent to me that stand out in my mind even now.  I completely understand his passion and am working very hard internally not to become a cork activist because knowing what I now know would make it very easy to do. I peppered him with a lot of questions, and I researched all of his answers. He was absolutely right on. I guess he’d have to be in order to maintain credibility in this highly controversial topic. This quote is the one that has stuck with me during this whole process:

“There has never been a peer reviewed or scientific study done to corroborate the outlandish claims of 5-10% spoilage of wines due to the natural cork closure. This a fallacy, perpetuated by those with a vested, financial interest in selling alternative closures. I’m happy to have you quote me on that.”

With everything that I’ve researched and read until my eyes bled, I can find absolutely nothing to refute that statement.  Which makes me feel that my previous intuition and statement that the claims of the screwcap and synthetic cork people were very highly exaggerated was absolutely right on. Another statement by Mr. Spencer which validates my affirmation regarding the “green”ness of the aluminum and plastic industries was:

“The aluminum industry has done a remarkable job at keeping its mining and production practices out of the general public’s eye. Also, aluminum is so ubiquitous in our world, much the same as plastics, that we have a hard time seeing them as potentially harmful to people or the planet for us.”

But you don’t have to believe me; here’s Mr. Spencer himself speaking at a TEDx conference in November:



I am not so foolish as to think that this is the end of the controversy.  Far from it; this will probably continue forever. The screwcap and synthetic people are often genuinely passionate about their belief in their products; however, because I’ve done the research and know what I now know, I can’t even begin to agree with them. But as I said in Part One, I have wines under screwcap. Some of them are quite good, although now that I know what I know, I won’t be keeping the better ones for a very long time with the intent of aging them.  I will continue to age only those under natural cork.  I will probably just bite the bullet and try my best not to purchase wines that have plastic closures. Ick. However, most of the cheap ones I like as daily drinkers are under synthetic.  And because box wines don’t last long – buy, open, gone in a few days – I will only be getting those sporadically anyway.

A recent research survey that asked people in the US, Germany, and Australia if they felt that bottles under natural cork could be said to be better, 93% said that the presence of cork in wine made them feel that it was a better quality than under any other closure.

Well of course.


My Resources:

(if a link does not work, please copy and paste in the search area of your browser)


Parenteral Drug Association Technical Report – PDA Technical Report No. 55 (TR 55) Detection and Mitigation of 2,4,6-Tribromoanisole and 2,4,6-Trichloroanisole Taints and Odors in the Pharmaceutical and Consumer Healthcare Industries

Practical Winery & Vineyard Journal, November/December 2008.

FDA: Drugs – Questions and Answers on Current Good Manufacturing Practices, Good Guidance Practices, Level 2 Guidance – Buildings and Facilities

Mustiness in Wine Bottled Without Cork? Pascal Jacquemettaz, University of Applied Sciences

Wine Pages – Aromas and Flavours

Experts raise a stink over screw-top wine bottles –

Geoff Taylor, Chemist:

From Bark to Wine Stopper to Footwear; the Story of Cork:—-the-story-of-cork.aspx 

MW dissertation claims that screwcaps cause more wine damage than cork

He speaks for the trees: “cork forests suffer from under use, not over use.”

Thiols – or mercaptans – are some of the smelliest substances you’ll find in the chemistry lab.

Cork vs. Plastic: How Real Cork is Harvested and Why It Matters

UCDavis ChemWiki: Thiols and Sulfides – Nucleophilicity of Sulfur Compounds –

Wood Pallet Industry Refutes Tylenol Recall Assertions –

Vintage Cellars – The Great Cork Debate: Natural vs. Synthetic vs. Screwcap

Amcor – Stelvin® FAQ –

Elmhurst College, Virtual Chembook. Conversion of Bauxite Ore to Aluminum Metal

Streamline MR Articles – Aluminum: How Sustainable is It?

Cork Forest Conservation Alliance

100% Cork: Approved by Nature


Current practices in pharmaceutical container closure development by Mauzey, Duane L., D.R.Sc., UNIVERSITY OF SOUTHERN CALIFORNIA, 2012, 138 pages; 3514255.

Screwcaps and reduction in wine

Wine Business Monthly – July 2008. Excessive Copper Fining of Wines Sealed Under Screwcaps: Identifying and Treating Reductive Winemaking Characters

The Drinks Business. Bark to Bottle: a Cork’s Journey

Plastics Europe. How Plastic is Made

Critical Reviews in Food Science and Nutrition, Volume 53, Issue 12, 2013
Determining the Applicability of Threshold of Toxicological Concern Approaches to Substances Found in Foods

Sealing Effectiveness Of Different Types of Closures Towards Volatile Phenols And Haloanisoles

Environment International, Volume 63, February 2014, Pages 19–25 Dietary exposure to phenolic and methoxylated organohalogen contaminants in relation to their concentrations in breast milk and serum in Japan (Abstract only. TBA in breast milk)

Handbook of Water Analysis, Third Edition. Chapter 4, Organoleptical Methodology.

Mercaptans & Reductive

Factors Impacting Sulfur-Like Off Odors in Wine and Winery Options, Bruce Zoecklein, Head, Enolog-Grape Chemistry Group. 8. Wine Closures and SLO (Sulfur-Like Off Odors) pp 15

Cornell University College of Agricultural and Life Sciences. Kicking up a Stink: Treatment for Sulfur Off Odors  First Publication April 2010

Thiols, Mercaptans, and the Stench from the French

Mercaptans and other volatile sulfur compounds in wine

Controlling Reductive Wine Aromas

Wine Business Monthly: Achieving Balance in Reductive Winemaking, October 2006

ACS Symposium Series. Fermentation and Post-Fermentation Factors Affecting Odor-Active Sulfur Compounds during Wine Bottle Storage, Abstract.

Authentic Wine: Toward Natural and Sustainable Winemaking, Jamie Good, Sam Harrop MW, Wine Faults, pp 209-211

Wine-searcher. Reductive or Reduced? Jane Anson. April 26, 2013.

Taints in Foods and Packaging

Australian Food and Grocery Council. Organohalogen Taints in Foods (note from Irene: this link may be faulty)
Organohalogen Taints in Foods – Australian Food and Grocery Council

Road Scholar. Food Supply Chain Risks Feb. 2013

FDA letter re McNeil Healthcare Inspection, 2010

Odors and Packaging Materials, November 2011

Go Plastic Pallets (promoted as an alternative to reduce pallet taint)

Pharmaceutical Recalls

Chemical & Engineering News, Central Science. “Wining” about Corked Tylenol. David Kroll, October 24, 2010

Lipitor Recall Issued for 191K Bottles Due to Musty Odor

Psych Central. Recall of Antipsychotics Risperdal Risperidone Issued. June 18,2019

Glenmark Generics, Ltd., Product recall statement

Moldy Antipsychotics Means Yet Another Recall For Johnson & Johnson

Time Magazine, Regulation. What is Causing that Musty Smell in Recalled Pills? Meredith Melnick, October 20, 2010

Alternative Uses for Cork,,20176738,00.html–linoleum-and-bamboo-flooring-244080422


World Wildlife Federation. Cork Oak (article about endangered animal species)

Wine Institute: Sustainable Winemaking


Coming next: You and I, Face to Face. On Cork. – Part Last




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