Let's play wine

NATURE

by Evagelos Soufleros

Tannins belong to one of the 4-5 families of phenolic compounds that exist in the various parts of the grape cluster and are, consequently, inherited in wines.  In larger quantities they are found in red wines which are meant to be aged due to the extraction that takes place during the processing of the grapes and during the contact of the must with the solid components of their berries.

 

The existence of phenolic compounds in wines and especially of tannins is what differentiates white wines with red wines and in a lesser degree rosé wines.

Phenolic compounds are responsible for the colour of wines, contribute in the formation of some of their taste characteristics (astringency and harshness), provide wines with antioxidant and antibacterial protection and play a decisive role in aging and in the various technological processes of the wine (e.g. fining).

Numerous current medical researches and the French Paradox (le paradox francais) confirm the positions and views of Hippocrates who considered wine to be of exceptional nutritional value and a unique cure for many ailments.

 

Nowadays, we are well aware that the properties that inhibit the action of the free radicals which contribute to the oxidation and formation of bad cholesterol (LDL), responsible for cardiovascular diseases, are owed to phenolic compounds (resveratrol, quercetin, etc,).

The comparison of Vitamin E (very useful antioxidant for the prevention of the oxidation of LDL) with resveratrol, quercetin, epicatechin and the other phenolic compounds showed, to the researchers' great surprise, that quercetin (flavone) and epicatechin (a precursor of tannin) are twice more powerful than resveratrol and that these three phenolic compounds are more effective than Vitamin E in protecting LDL cholesterol from oxidation.

Phenolic compounds are found in wines in higher concentration than in fruit and juices and they are absorbed adequately by the body.

 

The above characteristics of phenolic compounds make these ingredients exceptionally beneficial and I would dare say utterly necessary for the wines as far as what they have to offer to the wines themselves and the consumers.

We could say that it would not be possible to produce aging wines (vins de garde) without the adequate concentration of tannins.  This is evident with the red Beaujolais type wines or those of early consumption, as well as with the white wines which cannot age, exactly because their concentration in tannins is very low.  For this reason, if some red wines are relatively low in tannins and are meant to be aged, it is mandated that they remain in oak barrels in order to compensate for their lack of tannins.  Of course, the result of aging would be comparably better when the adequate quantity of tannins came form the grape with the proper wine making and mainly with the indicated time of contact between skin and must.

 

Aging of wine as counterbalance offers the wine improved taste after the recedence of the astringent and harsh taste and the increase in softness and velvety character.  This is achieved through the polymerization of the tannins and their conversion to macromolecular compounds and this does not allow their attachment to the glycoproteins of our saliva, resulting in avoiding the sedimentation of these complexes on the mucous of the oral cavity, which would cause the astringency.

The softer feeling is also owed to the reaction of the tannins with anthocyanins and other phenolic compounds resulting in their sedimentation during aging and their progressive dissociation which leads to smaller concentrations of the tannins in the wine.

The existence of tannins, combined of course with other characteristics, gives the wine the so-called “body”, making the wines robust and powerful with an increased sense of repleteness.

 

Nevertheless, there are two sides to every coin.  In this case also, tannins offer many advantages, but they also have disadvantages.  Excessive concentration makes the wine very astringent, bitter and harsh, impossible to be consumed not only while young but also after the aging, when the adequate balance is not there.

 

We are aware that the high quality of wines is the result of balance between the components which are organoleptically opposite.  The following equation describes the concept of balance in an effective way:

 

Acidic + Bitter + Astringent components = Sweet components

 

That is, the sum of the acidity of a wine (organic acids), the astringent and bitter taste (tannins, quinine salts) must balance out with the sum of the sweet taste coming from the residual sugar, the alcohol and glycerin.  Therefore, without the balance there are no high quality wines.

Consequently, the level of tannin concentration will depend on other components also, organic acids for example, and the counterbalancing weight of the sweet tasting components.  To achieve a satisfactory balance, the high alcoholic title and the adequate consistency of glycerine combined with low acidity, would allow the higher concentration of tannins and vice versa.

 

Authenticity of wines

 

In regards with the authenticity of a wine, we could say that it depends on or composed of: One the one hand the genuineness of the origin (on a geographical and varietal basis) and on the other hand the genuineness of the characteristics, that is, the lack of imitation/corruption of the original.

We could say that whether a wine maintains its authenticity or not in relation to the fewer or more tannins it may contain, falls under the second case that refers to the imitation/corruption of the original.

To answer the question of the level of mimicking other wines, wines from Cabernet Franc or Merlot for example, as to their consistency in tannins, is very difficult given that each variety has its own characteristics.  Nevertheless, the classic wines from Cabernet, even from Merlot, have a lot of tannins and a rich extract, in general.  They are, however, different as to the quality of the tannins.  The same also applies to the Nemea Agiorgitiko which has a lot of extract but at the same time less astringency.  Thus, the quality of the tannins is a significant regulator of the taste of red wines.

 

Thus, if we are seeking for a type of wine like Merlot or Agiorgitiko for Xinomavro, maybe this is impossible since Xinomavro has its own particularities.  Apart from that, we need to look at what happens with the balance of the components of Xinomavro, as discussed above, and look at the parameters which would “improve” or change the organoleptic sensation of Xinomavro wines: the most appropriate degree of technological maturation of the grapes, the lower yield of the vineyard, some specialised fertilization, other cultivation techniques, etc.

Any change that is administered in the organoleptic characteristics of the wine can be the result of consumer addiction to some wine standards, like Merlot, Cabernets or Syrah which became popular and well-liked and conquered the world.  Consumers, or rather their demands, nowadays, direct the winemaker or the oenologist as to what type of wine they will produce, whether we like it or not.  For this reason, every one of us involving ourselves with wine are heavily obligated to train the consumer right, to convince them to accept the diversity of each wine and its virtues, which can not be easily detected at a first glance.  Who wouldn’t be charmed, for example, by the excellent aromatic potential of Xinomavro, which coexists with the slightly weaker colour intensity and its particular flavour character with the authentic astringent taste?

 

Otherwise, which producer could remain loyal to their principles or to the authenticity of some products, if these were against the consumer preferences?

Improving the taste impressions, which is achieved through alternative methods of winemaking, perhaps shouldn’t frighten us.  Wine is produced to please the consumer and this will be achieved by ensuring the balance in the wine components, as mentioned before, and by the proper consumer training in order for them to be able to appreciate objectively each product, far from stereotypes and mimicry.  The diversity of the Greek grape varieties provides the ammunition upon which the efforts for exports should be based but also in convincing the Greek consumer to prefer our own products.

 

A comparison of results concerning the phenolic potential of wines from Xinomavro, a pure Greek variety with particular flavour character owed to the tannins and its acidity,   to the potential of some French varieties shows, in general, that the varieties Merlot, Cabernets and Syrah are rich in anthocyanins, tannins and a high degree of total phenols while Xinomavro has a relatively lower concentration in anthocyanins and slightly higher in tannins.  This correlation demonstrates that the analytical quantitative date would not be able to explain the flavour diversity of the two groups of wines.  The most probable version is the one of the different quality in tannins.  Simultaneously, these results justify the efforts to increase the concentration in anthocyanins with new methods without increasing the tannins at the same time.  Furthermore, we find that the colour intensity of Xinomavro is about three times less than in Merlot, Cabernets and Syrah.  Relatively smaller in Xinomavro are the total phenolic compounds, as well as the ionization index of the anthocyanins which is 2-4 times smaller, a fact that explains the weaker colour of Xinomavro.  It is known that ionized anthocyanins are those who contribute mainly in the colour of the tannins.

Far smaller in Xinomavro is also the HCI index (polymerization indication), about twice less compared to the French varieties.  This explains why Xinomavro is more astringent, since its tannins are not adequately polymerized in order for them to behave less astringently.

 

Wines that are produced with the aim of being consumed young, early, without aging, provide pleasure which is derived from the characteristics of the grape (aroma, taste) and the characteristics of fermentation.  However, they can not provide the Third dimension, which is bouquet, perfume, blossom aromas, as they lack this characteristic which is a result of long term extraction and aging.

ΤΗΕ ROLE OF THE TANNINS IN THE WINES

© 2015 MONOPOLE

OUR MAILING LIST

Evangelos Soufleros is Professor in Oenologie at Aristotle University of Thessaloniki. He is also the owner and winemaker of Petit Oineonas estate.