Although the tannic nature of some wines aid in maturation, there are some trains of thought that these tannins do not always lead to longevity in a wine. It’s a matter of balance.
Sometimes this tannic sense, or drying harshness is reflective of under-ripeness of fruit at harvest revealing the undeveloped nature of the fruit. The level of alcohol in a wine can also affect the perception of tannins, making the whole equation even more confusing.
The astringent taste represents the vines natural defence when grape and seed are ripening. Green as camouflage and bitter to the taste to ward off predators before seeds are ready to germinate. When ripe, the tannin in the skin colours the grape so as to attract the natural propagators. Clever really, essential to survival of the species.
Tannins are also introduced by the use of oak from barrels used to store and mature wine.
On our tours we suggest you take the opportunity to identify tannins and ask what value they add to the product, be it now or in the future. It will help towards the decision; do I drink this soon or put it away to enjoy another day.