Wednesday, March 5, 2014

Oxygen's Role in Aging Wine: Nomacorc - Part II -> Oxygen Management

After leaning about how Nomacorc manufactures their corcs and market share of closures (See Part I), the subject turned to an issue that I was on vaguely familiar - oxygen management. And this is a subject Nomacorc takes seriously> yes, their raison d'être was eliminating wines tainted with TCA; but they quickly pivoted to helping winemakers eliminate wine faults due to the (mis)management of oxygen.

In general, winemakers practice "reduction" techniques where they attempt to eliminate oxygen in most phases of the process. Small amounts of oxygen are needed at the beginning of fermentation as  oxygen encourages the yeast to multiply, but afterwards oxygen may encourage the spread of acetic acid bacteria or turn the wine off-color. Thus, winemakers try to eliminate oxygen elsewhere in the process by using sulfur, inert gases and stainless steel tanks and then topping off barrels lost to the angels. Usually winemakers are successful, but as this graph shows over a 5 year average,  about 5% of the wine were characterized as faulty due to oxygen (mis)management. And a similar study from the San Francisco Chronicle Wine Composition found 2.4% of the wines were faulty due to O2 management.

These oxygen (mis)management faults can be introduced in all phases of production, but this chart on Oxygen Management Objectives shows that the biggest variation in optimal oxygen exposure result from bottling, with smaller non-optimal exposure in materation and bottle aging. This chart was an eye-opener; I've witnessed some poor bottling techniques and I'm sure these wines aged poorly.

In order to assist winemakers to determine how much oxygen is imparted into a bottled wine, Nomacorc created the NomaSense™ Oxygen Analyzer System. These sets measure that amount of oxygen exposure in headspace of the bottle as well as the dissolved oxygen in the wine itself. Pretty cool.

Getting back to out Nomacorc sessions, first Vice President, Strategy & Innovation Malcolm Thompson presented Oxygen Management Strategy & Objectives - by showing how different closures provide different Oxygen Transmission Rates (OTR) which usually lead to different tasting wines. At the extremes these different rates can create oxidized or reduced faults, but in the median arbitrary transmission rates lead to different tasting wines - even when opened from the same case.  Wes Ward, Technical Sales Manager, Americas & South Africa, then lead a session on Oxygen as a  Winemaking Tool describing the chemistry and actual senses perceived due to different OTR. 

Nomacorc initially handled oxygen transfer rates by creating a closure that imparts a consistent rate for each and every Classic corc - all a result of their co-extrusion technology.  They eventually leveraged this technology to launch a new product line called the Select Series, which allows different (but consistent) oxygen transfer rates into the bottled wine. The Select Series consists of four corcs (100, 300, 500, 700), which will provide less to more transfer rates as the series progresses higher. But what corc should a winemaker choose for each varietal wine?  Nomacorc has automated this decision making process by creating the Noma Selector - as software application that guides the winemaker through the decision making process. Thus Nomacorc is confident that by utilizing their NomaSense™ analyzers with the Select Series, winemakers can improve and extend the shelf-life of every bottled wine.

But does it matter to the consumer which Select Series is utilized? Our final session of the visit tested this question by tasting a white and red wine bottled with three different Select Series corcs. We started with the 2012 Nyakas Budai Chardonnay by blind tasting three versions, and even with the short bottle aging, produced three completely different wines. The first glass was very light, citrus, with a lemongrass-acidic finish; whereas the second was more Burgundian with more minerality and depth.  The final glass was funky and the 500 series corc closing this wine had allowed the most oxygen to transfer. The first glass was corked with the 100 series and the second with the 300 series.

Our red blind tasting consisted of the 2009 Clos des Cordeliers Cabernet Franc which had been bottled with three different corcs in April 2011; providing three years of bottle aging. The first glass was a fruity wine, with plenty of cherry flavors and dusty tannins. The second glass was earthier, still a nice cherry flavor, finishing with smoother tannins. The final wine was musty, acidic, and not pleasing. Once again, three completely different wines, all bottled on the same day, but aging distinctly due to the Select series corcs utilized (300, 500, 700 in this instance).

The trip to Nomacorc was extremely informative and these sessions on Oxygen Management were a revelation in a noma-sense; another topic to discuss with winemakers on future visits.  And winemakers now have the tools to decide the proper closure for their wines. Some may choose to continue with natural cork; others like Jordan Harris of Tarara Winery will use strictly screwcaps. And others like Ben Mayo of Eberle Winery will continue to utilize Nomacorc Select Series in order to optimize oxygen transfer rates. Cheers

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