(Image via obenson's flickr)
For the longest time, I would read tasting notes and see that a wine had good structure. But, honestly, I had no idea what that meant. At first, I thought it must mean that it was big and bold, since it's often a word used with wines like Cabernet Sauvignon. And then I would run across a Riesling that was described as having a good structure. Huh? These wines are very different.
So I tried a Google search and found this: "structure: the way a wine is built; its composition and proportions." Hmmm. Clear as mud, right?
What I have come to learn through my studies with the International Sommelier Guild, is that structure is the components that support the body of the wine, just like a skeleton supports the human body. So in wine, it's the tannin, acid, sugar and alcohol that supports the luscious fruit. Without these components, any wine will be boring and flabby, no zip, no reason to want to sip again and again. These components make the fruit come alive in your mouth.
These also do something more. A well structured wine gives it the ability to age for many years, evolving into something different, more interesting. Tannin and acidity in particular can be particularly off-putting in a wines youth. However, with age, they will soften and blend into the fruit creating something spectacular, just like a good stew or chili become better the next day.