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Growing Grapes Better with Science: A Roundup of Recent Research on Wine Tannins

Sarah Williams

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Sarah Williams | November 1, 2013 | 0

Growing Grapes Better with Science: A Roundup of Recent Research on Wine Tannins

Making red wine is an art and science. More so as a science, generational wine makers would probably say. And this science, winemakers would also agree, revolves largely on “tannins” a component of wine that gives it color, dry aroma, texture and bitter taste.

Tannin, according to wine website Wine Folly, is a type of polyphenol found in most plants. The website also said that tannins in wine come from grapes or the barrel wherein it was aged.

Tannats is a grape species that have the highest concentration of tannins. In fact, according to a tannat-related article published by Science Daily News, Tannat-based wines contain twice the tannin concentrations of Cabernet Sauvignon. However, we all know that not all wines are made from tannat but other vinefera (grape) varieties.

Found below are some recent studies concerning tannin levels in wine that aim to improve the overall wine production process.

Discovering the Link between the Chemical Processes behind Wine Aroma and Grape Cultivation Conditions

Uruguay scientists are currently trying to find the link between the chemical processes that produce a wine’s aroma and color and environmental factors like temperature, climate, altitude and soil condition and composition. UNU-BIOLAC participants from Montevideo, Uruguay chemistry professor Francisco Carrau and scientist Massimo Delledonne from Italy have come together to sequence the genome of the tannat grape, whose seed pressings produce high tannin levels which serve as an effective antioxidant.

The two scientists will essentially make use of data from the genome sequences in grapes to determine the chemistry behind wine color and aroma. “Sequencing the grape’s genome will allow vinters to protect a valuable niche in the world’s $300 billion wine industry,” Carrau told Science News Daily.

“If we can determine through biotechnology the factors that determine a wine’s aroma and color, we can potentially apply that information to create more pleasing and valuable products,” Carrau continued.

“Such information can also valuably guide decisions about where to plant new vines, which typically produce their first fruit after five years and their best fruit in about a decade. Having the ability to predict successful vineyard location holds enormous value,” Carrau said in his interview.

Improving Tannins in Wine Can Improve Wine Taste and Body

Dr. James Kennedy, a researcher from the Department of Horticulture, Viticulture and Oenology in the University of Adelaide has conducted a study on how tannin levels in wine can be improved. Kennedy tried to prove three theories and found out that the first step in improving tannins in red wine is determining the stability/balance of tannins (theory 1), and finding out if the tannin structure has to be modified (theory 2 and 3).

Kennedy said the tannin quality of some red wines can only be improved if the tannins are balanced with other wine components like flavor and aroma, as with the case of the tannins extracted from ripe grapes. However, the structure of the tannins of the wine itself should also be need to be altered in other varieties.

Kennedy notes in his research that changing the tannin structures in wine could occur in the vineyards, wineries, and carefully choosing the sites where grapes are grown. It could also be achieved by changing “cultural practices” (for example, wine blending); maceration (soaking and pressing); and aging practices.

Supplementing Low Tannin Levels in Hybrid Wines

Hybrid wines are produced from hybrid grapes. As the name implies, these hybrids are made from crossing grape varieties. According to Jim Bruce of Grape Book, red hybrids tend to have more color and acid, and sweet. This, based on the findings of a Cornell University study, is perhaps due to the fact that hybrid grape solids absorb tannins more than its non-hybrid grape counterparts, leaving less extractable tannins, according to Pierro Spada, a columnist from Midwest Wine Press.

What are hybrid winemakers supposed to do then? According to Spada, researchers recommend the a shortcut: through enological (the study of wine) tannin additions. Scott Laboratories researchers said adding three different types of tannins—fermentation, cellaring, and finishing tannins—can significantly modify wine characteristics. Spada said that fermentation tannins are derived from grape solids (skins and seeds), oak wood and gallnut. Cellaring and finishing tannins on the other hand are derived from oak, or fruit and wood tannins, respectively, Spada said in his article.

Spada notes that the tannin amount would depend, of course, on what the wine maker aims to achieve, although he personally recommends adding moderate amounts of tannins to the wine then making use of cellaring or finishing tannins to modify wine structure.

The above studies only reflect the importance of adjusting tannin levels in creating the perfect wine. Until more scientific research on tannins come out, we can all just sit back and relax and enjoy our nip of our reds—or whites (if that’s your cup of tea). Learn a bit about wines from our Introductory to Wines course.

 

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