Update on Cork versus Screwcap

Update on Cork versus Screwcap and a take on DIAM versus SUBR

A recent exchange with a WSET diploma student was aprompt to do an update on my original cork vs screwcap blog post.

We love cork since it is a natural renewable resource and a great way to age wine. But pure cork has the potential to develop cork taint which we don’t want.


From an ecological standpoint, real cork is better than screwcap as it is a renewable resource whereas metal is not.
Cork Forest

A Cork Oak Forest in Portugal

From a health standpoint, having your wine in contact with cork is better than having it in contact with the plastic liner of a screwcap, which can leach plastic components into the wine. For me for long-term storage, cork wins based on this factor alone.

But the disappointment when you get a corked bottle (TCA) is nasty. As a producer we hate it. Some of the bottles we bought with the estate in 2005 had pretty bad levels of cork taint. We didn’t want that to happen  to our wine.


From our first bottling in 2007 to 2020 we used DIAM corks that were guaranteed no cork taint by a patented process called DIAMANT® they are called ‘DIAM’ – its cork pieces boiled then put back together with a polymer. As soon as it was available we moved to their DIAM Origine® made from cork that has been treated by their patented process then reconstituted with a beeswax emulsion and 100% vegetable ‘polyols’ and guaranteed for at least 10 years of aging (that is 10 years from when we bottle – most of our reds are bottled 3 years after vintage so this gives you a aging potential of at least 13 years on the reds and that is DIAMs published minimum).

Then DIAM Origine got so expensive we couldn’t keep buying them so we changed to SÜBR M50 which we trialled in 2020 and then went with the full range in 2021. We are very happy with them as they are based on real natural cork and a natural polymer (the polymer is sugar cane based).


Our first vintage (2006) reds were bottled in 2008 with a DIAM cork based closure. It has 15 years since bottling and 17 years since vintage and they are still going strong. SUBR is great so far – 3 years. It will be interesting to see in 10 years but the evolution looks very good, even better than the DIAM.


Discover the Feely Wine School, a WSET APP called French Wine Adventures and Read about the story of this organic farm – Caro Feely books. Join the mailing list to receive a seasonal newsletter, events, wine pairing, recipes and more info on this topic at the bottom right of this page.

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