“Karen, why do older cabernet sauvignons usually taste smoother than younger vintages of the same wine?” —Gemma B. (Petaluma, California)
Gemma, this is a great question. The causes are complex but one of the main reasons involves a process called polymerization. During polymerization, small molecules attach to one another and form long-chained molecules. In wine, polymerization occurs with tannins that, over time, form larger chains that then glide more evenly over the palate. If a cabernet is aged for, say, more than 15 years, some of those chains may get heavy enough to fall out of solution. In an old wine, this becomes part of what is called sediment.