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June 1, 2022

Cork Consistency w/ Francois Margot, Diam Corks

Cork Consistency w/ Francois Margot, Diam Corks

Francois Margot, Director of Sales, North America describes how Diam is creating corks with choices and consistency for aging, oxygen transfer, and initial oxygen release.


As the winemaker’s last choice before wines go in the bottle, cork has played an important role in wine ever since bottles could be made with consistent necks. The consistency of corks is another challenge that Diam is tackling. Francois Margot, Director of Sales, North America describes how Diam is creating corks with choices and consistency for aging, oxygen transfer, and initial oxygen release.

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Detailed Show Notes: 

Diam Corks

  • Cork was originally used for wine bottles when glass could be made with regular necks, chosen because it’s elastic to close the bottle
  • Elasticity goes down slowly over time
  • Regular corks are not consistent, Diam developed them to provide consistency
  • Consistency with structure and oxygen ingress - granulates corks (granulation spreads contamination everywhere) and then cleaned them (w/ supercritical CO2)
  • Cleaned to be undetectable by gas chromatography (down to 0.3 nanograms/liter)
  • Clean more than TCA, but all anisole molecules (150+ compounds)
  • Can choose the aging potential and amount of O2 ingress for wine needs

Cost of closures

  • Punch corks - different prices based on looks of closures (no impact on consistency)
  • Diam - 10-80 cents/cork

Value proposition of Diam

  • #1 - consistency – both in aging and oxygen transfer
  • #2 - Not tainting wine – if ~3% of wines are tainted, recover the full value; can detect TCA as low as 1 nanogram/liter, not 1 case of TCA in 20 years
  • Other producers sort corks
  • #3 – winemaker choice – able to choose closures based on desired evolution of the wine
  • Brand value – avoided destruction of brand value from tainted corks
  • No additional bottling line setup – e.g. – screwcaps require setting up a different bottling line with different components
  • Diam is not as sensitive to humidity vs. regular corks
  • Building the ROI – look at claims and returned bottles that will be avoided

Range of Diam products

  • Range based on aging capacity – 5-30 years
  • Range of OTRs (oxygen transfer rates) and OIRs (oxygen initial release) – 3 options of OTR and OIR
  • Oxygen ingress from corks in non-linear – initial oxygen enters wine from cork in the first 6 months (OIR), and then some oxygen passes through cork (OTR)
  • Wines for long aging may desire higher initial oxygen ingress (OIR), but lower long-term oxygen levels (OTR)
  • Began differentiating OTR and OIR 3 years ago

2 main patents

  • Cleaning process – removes 150+ compounds from cork
  • Re-building process – ensures elasticity of cork, contains 3 ingredients – cork (~95%), binding agents, beeswax/plastic microspheres which fill in holes and prevent moisture in the cork
  • Can use any thickness of cork, including thinner blocks, buys from the same producers as regular corks
  • Removes woody part of cork (lignin), which is up to 20-40% of bark, and uses it to burn for electricity; keeps suberin part, which is the elastic part

Burgundy premox issues – Diam has helped but the issue is not just the closure

Diam for sparkling wine

  • Regular corks are 24mm in diameter, Champagne corks 30-31mm in diameter
  • “Mytic” brand of Diam corks – same structure as regular Diam corks, but bigger diameter
  • Diam has ~30% market share for sparkling wine
  • CIVC doing research into O2 into wine
  • Coming out with cork for tirage next year to provide options vs crown caps, which give consistent OTR


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