10 full years with Diam

While the tests of Diam started at the beginning of the 2000s, the expansive use started in 2013 with Comte Lafon, in 2014 with Domaine Leflaive and Olivier Lamy in 2015 … 10 years ago … and things seem to work very well indeed from a premox perspective.

20 years since the start in Burgundy

Bouchard Père et Fils and William Fèvre in Chablis were some of the first to work with Diam closures back in 2003 and 2004 – the third estate that began then was Hugel in Alsace – so some estates are getting more and more experienced with the longer- and medium-term effects of using Diam in lieu of natural old school cork.

The main reason for using Diam is the premox problem … which has been reduced but not fully eliminated.

Diam is the solution for now … and will be maintained until other and better solutions become available.

One can discuss if the Premox will ever be eliminated when it is hidden and/or prevented by Diam … it works, and wines are now adapted to Diam by reducing the sulphur.

I fear that a lot of wines for Diam would not survive in a bottle with a regular cork. Or, should I say, many of them would not (variation in the permeability of the natural corks).

There are still changes to be made to adapt to Diam … and this will, no doubt, continue.

Diam in reds is another matter …. I can understand it, but the burning platform is not there as red wines keep well under natural corks.

The Diam corks …

Diam supply the following corks Diam 2, Diam 3, Diam 5, Diam 10 and Diam 30. The three top ones are usually used in Burgundy.

Diam 5 will let through more oxygen (higher permeability) than the Diam 10 and even to a higher degree than Diam 30. The Diam 5 is used for the lesser wines, as these will be consumed fairly early, and this will ensure some ageing in bottle with the higher permeability of the Diam 5.

Fèvre experiences

In 2017, I had the the pleasure of interviewing of Didier Séguier of William Fèvre about their experience with the Diam closures. Bouchard Père et Fils and William Fèvre were some of the first to work with Diam closures back in 2003 and 2004 – the third estate that began then was Hugel in Alsace – so there are no estates that have more experience with the longer- and medium-term effects of using Diam versus natural old school cork.

Photo Didier Séguier – source Domaine William Fèvre

It should be noted that William Fèvre was then owned by Henriot, as was Bouchard Père et Fils in Beaune – and the winemakers – Philippe Prost (until 2014) the winemaker at Bouchard and Didier Séguier at William Fèvre have undertaken extensive tests with Diam from the very beginning, starting in 2003, when the closure was first introduced.

William Fèvre now has 20 years of experience in working with Diam – first, for testing and later, for commercial bottling. This means that they now have witnessed the effects on the wine that have been cellared and matured around 20 years with a Diam closure.

For me, these experiences are very important for the collectors of white Burgundies, at least, for those who like to drink fully mature wines – i.e. 20 – 30 years of ageing depending on classification level.

Fèvre first started experimenting with the Diam closure in 2003 and then began bottling its Petit Chablis and Chablis with Diam 5 from the 2005 vintage.

William Fèvre began using Diam 5 for its Premier Cru Chablis from the 2007 vintage.

From the 2010 vintage, all the Grand Crus have been bottled with the Diam 10 closure, and these closures are now also used for the Chablis 1er Crus.

It is important to notice that the development in bottles using the Diam corks is affected by the amount of sulphur used during vinification and bottling. Furthermore, the type of Diam determines how fast the wine develops, or ages, in bottle.

The level of SO2 and the Diam cork

The level of sulphur, or SO2, is very important for conserving the wines and preventing premox – with Diam, there is no or minimal variation in the closures – and lesser permeability i.e. oxidation through the closure.

William Fèvre has reduced the level of SO2 at bottling by 20% from 40 to 30 mg/l as a consequence of using the Diam closure. This is to get a balanced development of the wines – the Diam cork will slow development on the bottle, but when compensated with a lower level of SO2, it ensures that the wine ages in the bottle at a fairly normal speed.

If the level of SO2 is maintained, one could see that the wines will develop quite slowly after changing to Diam when compared to a wine bottled with a natural cork.

Summing up the Diam discussion

The Diam closure is the route that most top-end producers seem to take in the fight against premox – and for me, this is both understandable and needed – there are really little or no alternatives it seems.

But then again … why can Coche Dury make wines with regular corks with so little issues !!!