NORREL ROBERTSON, Master of Wine, WINEMAKER & CONSULTANT, CALATAYUD , SPAIN

During the 2008 vintage in Calatayud, Spain, we carried out full scale production trials with the new Lalvin Clos yeast (YSEO).

As this yeast had been isolated from Grenache and Carignan grapes in the Priorat in Spain based on an ability to produce high quality wines with fine tannins, well integrated alcohol, lower than normal volatile acidity and a reinforced mineral character, we wanted to see the effect on Garnacha and Tempranillo grapes from another extreme climate in Spain. Typically musts from Calatayud have high potential alcohol, are prone to elevated levels of VA, and due to a combination of a dry climate and high alcohol, the tannin management can also be difficult resulting in wines that are too dry and astringent.

In Calatayud we trialed the lalvin Clos yeast alongside BRL97 (a Nebbiolo isolate from Barolo favoured for colour enhancement and full bodied wines) on two ’doble pasta’ fermentations of old vine Garnacha and Tempranillo to provide extreme conditions where nutrition, yeast stress and tannin management can pose difficulties for the yeasts.

The results confirmed the preliminary findings outlined in the development of Lalvin Clos. The Lalvin Clos yeast exhibited a very good implantation and a very short lag phase compared to BRL97. Similarly alcohol level and VA level were both slightly reduced in the wine made with Lalvin Clos. However, perhaps the most important feature of the trial was the organoleptic differences witnessed between the two wines. The wine fermented with Clos had a better definition of tannins and more harmony within the tannic structure. Whilst displaying less red fruit and less upfront fruit characters on the nose and palate, the Clos wine was viewed to be more complex in blind tastings with other winemakers with an accent on minerality, length and more complete, complex flavours.