Vertical tasting refers to tasting the same wine—produced under the same appellation, from the same estate, and made from the same grape varieties—across different vintages. The principle is to travel through time by comparing the various vintages in order to observe how the wine evolves. This type of tasting is highly instructive, as it helps train the palate to distinguish a young wine (with fruity aromas and pronounced tannins) from a more mature wine (with tertiary aromas and softened, integrated tannins).