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

The Rise of Synthethic Corks: Nomacorc - Part I -> The Plant Tour

The last few years have witnessed a debate on the proper wine closures - whether natural cork, synthetic corks, and screw caps. This debate has sometimes been serious, other times completely hysterical - but a debate that will continue indefinitely.  Natural cork, made from the bark of Cork Oaks, remains the traditional closure choice (60%), but carries some baggage in the form of "cork taint" (3% of wines closed with cork are affected by TCA), expense, and uncontrollable rates of oxygen transfer into the wine - at the most extreme leading to oxidized wine.  Screw caps are a rising player and close 27% of wines - all of New Zealands and most from Australia.  I appreciate the portability and ease of opening these closures, but on the flip side there are arguments about how long a wine closed with screw caps can age and since these closures allow practically no oxygen to permeate, these wines are susceptible to reductive attributes. Synthetic corks are the third major player, and whereas we all can agree that the hard injected molded plastic corks are disagreeable, I will feature the world's world's leading producer of synthetic corks, Nomacorc.

Last week Nomacorc hosted myself and five other wine bloggers and writers (Ben Carter, Cath Monahan, Michelle Locke, Luke Whittall, and Mads Jordansen) to their Zebulon, North Carolina plant for a tour and a presentation of their products.We learned quite a handful over these two days, starting with the company's background.  It all started when businessman and wine connoisseur Gert Noël opened several bottles of wine that had been tainted with TCA. With his son Marc, they used their experience in foam extrusion technology to develop a synthetic cork that consists of  a foamed core and an outer skin. Marc officially formed Nomacorc in 1999 as they released their first corc - Classic. Over the years, the company has grown to hold 13% share (2012) of the total wine closure market (2.2 billion corks) while adding several new corcs to their portfolio - all designed to to allow winemakers different options in oxygen transfer rates. This topic requires it's own post - coming soon.  

Our visit began with introductions and an overview by President and CEO Lars von Kantzow. He also described the uniqueness of Nomacorc's corcs.  They are produced by a patented co-extrusion technology where The skin is flexible yet provides a tight neck seal that eliminates leaking and protects the core foam from crumbling. This foam core has a uniform cell structure that provides a "consistent, predictable oxygen permeation that eliminating off-flavors due to oxidation, reduction, or cork taint".

We then dressed for the plant tour - hair nets, gowns, ear plugs and radios in order to communicate over the running machinery. But before entering the plant itself, we stepped into the Sensory Laboratory, which is one phase of the company's quality assurance implementation. Antoinette Morano, Sensory Services Lab Manager, described to us how the lab is intended to "ensure that their wine closures are completely sensory neutral". The lab is a controlled non odorous environment where her team evaluates the raw materials and finished goods. This process also includes inspecting delivery trucks and pallets.  The laboratory also evaluates wines closed with Nomacorc closures to ensure that the corcs are not affecting the character of the wines they protect.

We then entered the physical plant and yes, the ear plugs and radios were necessary. There is a wall that contains a display case of wines closed with Nomacorc closures as well as samples of the raw materials, co-extruded synthetic material, and the finished product.

How are the corcs manufacured?

"First, raw materials are mixed, melted, and extruded to create a long, foamed cylinder, forming the closure’s core. Then a second extrusion process applies a flexible outer skin, which is thermally bonded to the inner cylinder. The shape is stabilized in cooling water before our high-speed cutting operation cuts the closures to the proper length."

As we witnessed, this process is continuous, leading to a consistent product - no variations or inconsistencies due to batch processing. The machinery was quite fascinating - I always wonder how they even build the machinery that makes the machinery and so on down the line. The process from inputting the raw materials to the co-extrusion itself, where the outer skin and foam core are extruded together, was rather anti-climatic. The most interesting parts did not occur until after the co-extrusion process where a laser controls for size and shape and when the corcs are cut into exact lengths. And I did notice one set of corcs failed and rejected by the laser. Another interesting aspect was their ink adhesive process where the company can now stamp their corcs on both ends as well as the standard sides.

I had read other visitors comment about the amount of water used to cool the synthetic material - but in my opinion - it wasn't out of the ordinary of similar cooling operations and Plant Manager, John Wojcik, stated that the water is sent to the sewer in better shape then from the tap. 

After we finished the plant tour we listened to Ben Mayo of Eberle Winery in Paso Robles describe his customer experience from using several Nomacorc closures over the past ten years. He said they turned to Nomacorc because of supply issues from natural cork and experiencing a 2-3% return rate from TCA. And during the past decade he has never had one of his customers complain or even mention the closure. Mayo feels strongly that the Nomacorc closures slow the aging process and he has never witnessed cord dust or a crumbling cork in his wines.  We then sampled the Eberle 2003 Reserve Cabernet Sauvignon closed by Nomacorc's Classic corc. And yes, it had held up, it seemed like a young wine - plenty of blackberry and dark cherry aromas and flavor with no signs of reduction - just smooth chewy tannins. Mayo explained that these characters are a result of the closure's oxygen management - which we will turn to in Part II.