Legs in a wine glass form when you swirl a wine in a glass and then set it down — they are the little “drippy” lines that form as the wine slowly settles from the edge of the glass back down towards the bowl with the rest of the wine. It’s easier to illustrate visually:

There are two separate questions here: (1) What are the legs? And, (2) Do legs in a wine glass indicate anything about the wine’s quality?

The legs in a wine glass are a visual representation of viscosity, i.e. the thickness of the wine in the glass. To conceptualize this, you can imagine, for instance, water. Water is not viscous. If you were to swirl a glass of water and set it down, all of the water will drop almost immediately back into the remaining pool of liquid with none of it coating and clinging to the sides of the glass. On the opposite end of the spectrum, if you were to imagine a glass of maple syrup, that’s highly viscous. Swirl a glass of maple syrup and set it down, and you’ll see that the little “drippy” things will coat the side of the glass and cling to it for a long time. These are the extreme ends of the spectrum for viscosity in wine — wine will (almost) never be as viscous as maple syrup* nor will it be as non-viscous or runny as water, but these examples illustrate the concept.

What drives viscosity in wine are two primary components: sugar and alcohol. Again, picture maple syrup or even simple syrup (which is just sugar and water) — the dissolved sugar makes the water thicker and more viscous. When we see legs in a wine glass, though, we cannot tell with our eyes whether the viscosity is driven by sugar or alcohol. This is one of the reasons why you’ll hear me say repeatedly during the unPINNED Wine course that you should always trust your palate. Beyond this, wines that are more saturated in color will appear to be more viscous when looking at the legs because higher color saturation makes the legs easier to see. It’s only when we taste the wine, that we’ll be able to discern what of the viscosity is being driven by sugar vs. alcohol (or potentially even sediment — this is a story for another time).

Now that we have a clear understanding of what legs are, we somewhat naturally have an answer to our second question as well. If the legs only tell us about the viscosity of a wine, can we draw a meaningful conclusion about the quality of that wine by looking at just the legs? No, of course not! To try and determine the quality of a wine based on the legs alone would be the cliché equivalent of judging a book by its cover, or perhaps even worse. At least the cover of a book was designed to try and represent what the book is about — the legs in a wine are not!

The legs in wine are simply an interesting phenomenon to observe in a wine glass because we tend not to drink many other beverages in a glass of the same shape or pour liquids in similar quantities. Other than that, the legs don’t really tell us that much about a wine. Trust your palate a whole lot more than you trust your eyes!

*Tokaj Eszencia is the only real exception that comes close.