Q&a With Eleonor Visser

As the world’s second-largest cork closure manufacturer, Diam Bouchage has built its success and reputation on innovation and patented technologies – including the celebrated Diamant process, which produces taint-free cork closures.

WineLand asked Eleonor Visser, oenologist and consultant for DIAM in South Africa, about the recent advancements and future of technical cork closures.

Eleanor obtained a BSc in Agriculture (Viticulture and Oenology) from Stellenbosch University and gained international winemaking experience at Quail Ridge in Napa Valley, California, and Hazelgrove in McLaren Vale, Australia, before starting her winemaking career in South Africa with positions at Thelema, Spier, and Rudera. She joined Diam in 2018.

Eleonor Visser, DIAM oenologist and consultant.

What percentage of your production now goes to technical cork versus natural cork?

Since 2004, DIAM has decided to switch all production to DIAMANT technology and has stopped producing natural cork.

What are the most significant technical developments in composite cork technology and manufacturing during this time?

DIAMANT technology and the use of supercritical CO2 with differentiated pressure has been a disruptive innovation in a cork market that was in great difficulty 20 years ago. Ensuring perfect homogeneity, organoleptic neutrality and control of permeability did not exist at that time with cork stoppers. And this technology remains the most efficient today.

What drives greater adoption of technical corks for premium and high-end wines among producers?

Premium and high-end producers still prefer the use of cork stoppers for iconic wines, but can no longer afford the defects associated with punched corks. They come to DIAM for an oenological cork closure that respects wine’s aromatic profile, ensures perfect consistency from one bottle to another, prevents leaking, seeping, and dust issues, preserves free SO₂, and avoids primitive oxidation.

Which of your products address this high-end market, and how are they unique?

We offer DIAM 5, DIAM 10 and DIAM 30 and Origine by DIAM (bio-based) for still wines, MYTIK DIAM 5 and MYTIK DIAM 10 for sparkling wines, and SETOP Element for spirits.

Oenological corks have become the new tradition and iconic wine producers are now using DIAM to protect their wines. Still, some winemakers prefer the look of a punched cork, that is why we developed Collection by DIAM, which offers all the advantages of DIAM but with a traditional aesthetic.

What does testing show about the aging performance of technical corks?

Over the last 20 years and thousands of tastings with our clients and oenological experts, DIAM emphasised that oenological corks prevent oxidation by keeping 30% more free SO2 than traditional punched corks or synthetic stoppers.

A recent 10-year study managed by AWRI in Australia showcased that after long storage, DIAM 30 has yielded the best results in terms of permeability control and organoleptic neutrality.