Warning! This Is Going To Be Dry (like my humor)

What are tannins? I can't tell you how often, in my tasting-room role, I'm asked this simple question. The problem is that you can give a relatively simple answer like:

Tannins: a group of chemical compounds or phenolics found predominantly in the skins, seeds and stems of grapes. Tannins are vital to a wine's profile as they are partly responsible for its taste and sensory properties. They also play an important part in stabilizing the color of red wines by binding with the anthocyanins. Tannins in wine are also derived from oak, during both barrel maturation and barrel fermentation.

But then the guests stare at you with a blank face until they further qualify their original question while reading some of the descriptions on our wine menu:
"So what's the difference between this, pointing, 'with moderate tannins,' this, again pointing, 'soft tannins,' this, almost stabbing the menu with their finger, ' well-structured with integrated tannins,' and, finally, this 'with lingering tannins'?"
I certainly can't blame the relative newcomers or even the more advanced wine geeks for needing more information on this enigmatic element of red wines. I'll give it a try though.

Two of the basic truths of these terms are that "grippy" tannins (i.e. those that make your lip adhere or grip to your teeth) only come from the grapes themselves, while soft or smooth tannins originate from the oak in the aging process. And, speaking of the aging process, tannins are what allow many red wines to age gracefully. The tannins are said to diminish or soften with time, so that a wine that tastes very harsh when young can reasonably be expected to age well in 7-10 years or more.

Here's a partial list of higher-tannic wines, and therefore, those that can be cellared a few years with a beneficial softening of those harsh young tannins (maybe that's why my father would say he would "tan my hide!"):

Cabernet Sauvignon
Nebbiolo (i.e. Barolo, Barbaresco)
Tempranillo
Syrah
Montepulciano

Now for those wines with lower tannins:

Pinot Noir
Zinfandel
Barbera
Gamay (i.e. Beaujolais)
Merlot

Interestingly, the thicker the skin of the grape, the greater concentration of tannins.