Bruni Erben: A barrel full of Tannin?

Tannins, extracted during the wine-making process, are important contributors of depth of flavour, colour and mouthfeel, features of wine that are directly associated with quality. The use of wood during fermentation and maturation can supplement these qualities in the wine through the extraction of ellagitannins and flavour compounds to compliment or enhance a certain wine style. The source, toasting, quantity and quality of oak are key factors in determining what level of extraction of tannins and flavour compounds takes place.

The main wood sources are Sessile (Quercus petraea) and Pedunculate (Quercus robur) oak, which are traditionally grouped together under the label of French oak. Imported American oak (Quercus alba) is also used in the wine industry. The key compounds in oak species that are of oneonlogical significance are Ellagitannins, Vanillin, Eugenol and β-methyl-y-octalactones (MOL).

Ellagitannins are a complex group of C-glycosidic bonded hydrolysable tannins. Over 500 members of this family have been isolated from various plant species and fully characterised. They function differently to tannins, and are more stable and therefore more easily quantified. These tannins add structure to wine as the polymers interact with salivary proteins adding complexity and astringency. The most common compounds from oak species are found at the highest concentration in the French Pedunculate Oak. The presence of these ellagitannins gives an increase in perceived weight, body and mouthfeel to the consumer. Methyl-octolactone trans- and cis- isomers MOL are highly volatile compounds which give a sensory contribution of predominantly coconut profile in high concentrations. The toasting process is a key factor in reducing this compound in the wood and limiting the extraction into wine. Eugenol is another important compound stemming from the toasting process, which gives off a spicy sensory profile. Vanillin, more present in American oak may increase following toasting but can diminish if high temperature and prolonged toasting takes place. Smoky “taint” stems from prolonged toasting which diminish ellagitannins and eugenol compounds, ultimately increasing furanic compounds that can give caramel notes, but may also increase Guaiacol to a point where the dominant character may become an overly smoky flavour.

Since 2006, oak alternatives have been accepted for use in wine ageing and fermentation by the European community (EC regulation CE 1507/06 for using oak pieces in maturation and EC regulation 606/2009 for in-fermentation).

All of these important compounds extracted from the oak is lower in used barrels shown in graph below. The ellagic tannin protective effect is decreased and the wine becomes subject to premature oxidation. Adding Quertanin® allows recreation of the buffering qualities provided by tannins extracted from new barrels thus protecting the wine from the oxidation phenomena. Laffort offer a wide range of finishing tannins to boost tannin content in wine that comes from a variety of preparations of “stave wood”- quality ellagic tannins, extracted from oak heartwood (Quertanin®, Quertanin® Sweet & Quertanin® Intense NF) or ellagic tannins sourced from oak heartwood and gallic tannins (Quertanin® Choc’) in instant-dissolving form (IDP), for the maturation of white, rosé and red wines.

Tanfresh®  is suitable for white and rosé wines and is a combination of ellagic and proanthocyanidic tannin based on grape tannins.

υ To refresh white and rosé wine (against oxidation, atypical ageing). 

υ To boost structure and mouthfeel. 

υ To help eliminate reductive odours. Dosage: 0.5 – 6 g/hL

Quertanin® Quertanin® Sweet Quertanin® Choc’ Quertanin® Intense 

υ Regulates oxidation-reduction phenomena during maturation in barrels or during micro-oxygenation. 

υ With used barrels, the Quertanin® range allows the recreation of a medium rich in ellagic tannins similar to a new barrel. 

υ After the addition, it is recommended to carry out normal rackings until fining or bottling preparation. 

Sample/tester kits to trial on your wine are available on request.

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