When you’re tasting wine, it’s tempting to focus on smells and flavors to the exclusion of all else. After all, noting what a wine smells or tastes like lets us compare it to things that are already familiar — “that reminds me of grapefruit!” or “does anyone else taste blackberries?” But it’s just as important to think about a wine’s structural elements, too. These four elements are alcohol, sugar, acidity, and tannin and they go a long way toward explaining how a wine actually feels in your mouth. I know this sounds a bit wonky, but bear with me (that’s why I used a Beatles reference for the title of my post, rather than calling it something like “understanding structural elements in wine”).

Generally speaking, alcohol and sugar are going to make wine feel fuller and softer in your mouth, whereas acidity and tannin are going to make the wine sharper and harder, bringing it into focus. A well-balanced wine is one where all of these elements are in equilibrium, so that no single one of them overwhelms the wine.

OK, so what do I mean by “softer” and “fuller”? Most of us are pretty familiar with how sugar plays this role. Just think about taking a swig of Coke vs. the Diet Coke and you get the difference. The real thing feels richer and has more presence in your mouth than the diet variety. Alcohol gives the wine similar qualities — compare a low alcohol white-wine spritzer (does anyone even drink those anymore?) to a glass of Port, and it’s clear which one is heavier in your mouth. The “weight” of wine in your mouth, for lack of a better way to describe it, is what we mean when we talk about a wine’s body. You’re probably much better at discerning this than you think you are.  After all, if you’re used to drinking cream (which, in winespeak, would be “full-bodied”) in your coffee and substitute medium-bodied half-and-half or, God forbid, very light-bodied skim milk, chances are you can feel that difference from the very first sip.

Acidity helps to cut through some of this softness and provides refreshment. If you cook, you know how a squeeze of lemon or splash of vinegar can liven up a dish right before you serve it. Acidity also makes you salivate, which helps to promote digestion — and, at least in my case, makes me hungry. (Which probably explains why I eat a bigger lunch after downing too many mid-morning Gummy Bear sours.) Tannin is a little less intuitive. In your mouth, tannin creates a tight, drying sensation. Think of oversteeped tea or walnut skins. While that doesn’t sound particularly pleasant on its own, tannin — found pretty much exclusively in red and rose wines — plays a huge role in giving wine its backbone. Without enough tannin, a wine turns into a kind of boozy fruit soup. (Some cheap Australian and American reds suffer from this very problem.)

Assessing these structural elements in wine isn’t always easy. Acidity and tannin are particularly hard, and it can be tricky for the beginning (or even intermediate) taster to discern between the two. But understanding how these four components work together, and finding out what combination of them pleases you most, will go a long way toward helping you find wines you like.