As discussed in previous postings, longevity may be considered within the pantheon of wine quality. The reductive strength of a wine is a measure of oxygen uptake and the ability to handle that uptake, that is improve with age. In red wines this is influenced principally by phenols and impacted by several winemaking protocols.
In a recent study (Kassas and Kennedy 2011) wines commanding the highest market value had several attributes in common including the highest concentrations of total tannins, the highest concentration of skin tannins and tannin-anthocyanin bound pigment polymers.
In grapes and wines, anthocyanin pigments can be either free monomers, that is, unbound, or associated with other compounds including phenols such as tannins to form polymers.
Tannin polymerization in fruit and wine continues until an anthocyanin molecule binds the terminal ends of the tannin chain forming ‘bookends’, thus stopping the polymerization. As such, the ratio of anthocyanins to tannins is important. This ratio impacts the extent of polymerization and, therefore, astringency.
Large tannin-tannin and tannin-anthocyanin polymers provide a relatively large number of binding sites to interact with proteins, as well as salivary proteins. As such, wines with an abundance of large polymers tend to lack softness and often possess a dry mouth sensation.
Conversely, smaller polymers have fewer protein binding sites and produce less astringency while providing a softer mouthfeel and often more palate depth. These smaller polymers are associated with enhanced reductive strength and wine aging potential.
Some phenols (diphenols) have the ability to react with oxygen, bind with another phenol, and recreate the original structure-thus allowing it to react over and over again. This helps explain the rather counter intuitive feature of exposing a young wine to oxygen and making that wine more resistant to oxidation. Young red wines can consume oxygen, actually increasing reductive strength.
Randall Grahm of Bonny Doon Vineyards in California considers reductive strength to be analogous to a wine’s chi or, as the Chinese say, life force. When a wine is young, it can share its chi with the world; when old, it must guard it so the wine does not diminish too quickly. Young wines have a capacity to adsorb oxygen and that can actually increase its resistance to later oxidation. Irrespective of chi, we believe that reductive strength is related to the phenolic composition of a wine and, therefore, to longevity.
“Experience is the name everyone give to the their mistakes” - Oscar Wilde
Dr Bruce Zoecklein is a Professor Emeritus, Enology-Grape Chemistry Group Virginia Tech.
His Enology Notes are available at www.vtwines.info.
When in 1939, Rhett Butler quoted the memorable “how fickle is woman…” he obviously did not have any idea how complex consumers can be…But if one thing is true about consumers, it is the fact that they demand top quality for no dollars!
What does the consumer want? I reckon 99% of consumers want drinkability in what ever they may take from the shelve. And “drinkability” is one of those abstract terms with so many meanings and definitions. For me drinkability is a function of how well the winemaker interpreted the phenolic personality of a given block (or cultivar), and how the processing dynamics were being managed early in the life of the wine to obtain a wine which has loads of fruit, and soft and subtle tannins which are protected by complexing factors such as mannoproteins and colloids.
There are numerous ways to achieve this, and we know what important role oxygen plays not only in achieving this, but also in increasing the viability of yeasts and getting rid of bad flavours like H2S. Various winemakers have experience with a number of cap management regimes, but in most instances various levels of oxygen is incorporated in the process. Obviously different strokes for different blokes.
Pulsair is one of these techniques. I stumbled upon this technology at an exhibition almost six years ago. More recently I saw fixed installations and even handheld units at various cellars in Australia. Yalumba has a fixed system on most of their red fermentation tanks.
How does it work? It works on the sequential release of compressed air or gas at the bottom of a tank for the purpose of creating circulation and mixing. Measured amounts of high pressure air are injected under flat round discs called accumulator plates installed on the tank bottom. It looks just like a creepy crawly. These released bubbles become bigger as they rise to the surface, and bubbles through the cap mixing the fermenting must very efficiently with the pomace.
The result? Soft luscious wines with loads of fruit.
I think winemakers should think a bit more out of the box when it comes to buying expensive oak barrels, and perhaps think more about savings down stream. The clever application of simple technology can certainly swing the bottom-line.
See pulsair in action on YouTube
If the title of this blog caught your eye, my ploy worked. Please accept my apologies; Flash Gordon will not be featured here. Or any other superheroes, for that matter. I will however elaborate on Flash Détente and its super colour-extraction abilities.
Of late, growing interest in colour extraction (especially in California) has led to the evolution of thermovinification into Flash-Détente. During thermovinification, the temperature of crushed red grapes is raised to 60˚C for anything from one to 24 hours. Thermophiles (pardon the pun) claim that increased tannin and colour extraction is to be had with thermovinification. The logic behind this is sound, as the high temperature breaks down cell structures. This in turn releases pigments, tannins and volatile compounds in the absence of ethanol. In the absence of alcohol, chemical bonds are formed between anthocyanin pigments and other phenols which stabilizes colour in the resulting wine. Should this concept give you cold feet, you might want to opt for cold soaking. During cold soaking, crushed grapes are soaked in their own chilly juices and pumped over for a few days in an effort to extract more colour.
Not impressed yet? Enter Flash-Détente, which is basically thermovinification on steroids. Grapes are briefly (two to five minutes) heated to 85˚C and then cooled in a vacuum. Cell walls pop, juices fly and a myriad of aroma and colour compounds are released. The vaporised water (with volatile compounds trapped within) is then chilled in a condensing column, after which the winemaker is left with the decision of adding the fluid fraction back to the main tank or not. Seeing that this condensate is full of pyrazines and in the case of lower quality grapes, rot and mold aroma compounds, the winemaker usually discards the condensate. This is however a double- edged sword, as varietal and fruity aromas is also lost in the condensate. Then again, the heat application inhibits enzymes such as polyphenol oxidase and laccase, which are often present in lower quality grapes. The effect of this heat on Brettanomyces is still ambiguous. Other benefits of extracting colour earlier are; improvement of purple hues in wine, fermentation at lower temperature and usage of different yeast strains. It is also speculated that the softer and rounder tannins are better extracted with water and heat, while the harsher tannins might be brought out where ethanol is the solvent.
Many traditional winemakers believe that Flash-Détente is for higher yield facilities, where often quantity outweighs quality (sic). It has been said that the loss of varietal character often results in a one-dimensional, soulless wine. As with all other winemaking decisions, the decision to go with or without thermovinification is an important one. Current studies on thermovinification are focusing on changing tannin concentrations in must with an increase in temperature and how varietal character is affected.
With a price-tag of $2 million for a Flash-Détente set-up, winemaker experience will be key in the decision to employ this system or not. Like they say, talk is cheap.
Bernard Mocke is a technical consultant for Oenobrands.
The cooperative Vinicola de Villarobledo has been the only winery from La Mancha region to win a Gold award at wine contest – Nuevo Vino 2011 – held in Madrid on the 15th of June this year. This was the first time the cooperative winery presented a wine to this contest.
Martin Pardin (technical director of the cooperative) explains he wanted to innovate and create a very complex and unique red wine, adapted to modern demand for fruitiness, roundness and complexity in red wine. Grapes from Syrah, Tempranillo and Garnacha were partially destemmed, crushed and barrel fermented separately in 3rd fill French oak barrels. Martin used an extraction enzyme and a new yeast from Oenobrands, Anchor Exotics SPH, in all barrels. This yeast is an interspecies hybrid between Saccharomyces cerevisiae and Saccharomyces paradoxus. It is the only yeast of its kind worldwide. Fermentation took ten days at temperature range 18-27 °C, with four hand pigeage daily. For yeast nutrition, Biovin (bio-regulator of La Littorale) has been added after density of 1040. Martin was very happy with the results obtained with Anchor Exotics SPH as it satisfied his need to create a “highly fruity and complex red wine, different from a standard red wine of La Mancha region”.
Malolactic fermentation started spontaneously immediately after alcoholic fermentation and was completed within one month. The wines from the three varieties were blended and stored for five months. No fining was applied before bottling and Mannostab (Laffort) was added to secure tartrate stability.
Martin is very happy with the recognition this award gives to his winery and region, since all the other wines awarded came from other prestigious Spanish wine regions. He plans to increase production with his approach and will continue use of Anchor Exotics SPH as “a perfect tool to help him achieve complexity and fruitiness “. At the moment the wine is only available for sale in Spain but an extension of production in 2011 will allow the winery to have the wine available for export markets.
Patrice Pellerin is the technical manager for Oenobrands.