Do you get mesmerized as you swirl your wine glass with those gorgeous “Rockette-style dancing legs” as they bead down your glass? Does this mean that the wine is sexier or a bit risqué if it has legs?
Is it myth or fact, can you determine quality, alcohol percentage, and sweetness by solely examining the wine legs in your glass?
Occasionally, you will see someone swirl their glass of wine, raise it towards the light, and watch with bated breath for their wine legs to appear. Wine enthusiasts will often interchangeably use one of these common phrases of “tears of wine”- the French tend to use this romantic phrase more often - or “wine legs”.
What exactly are wine legs, and what does it look like?
Wine legs are the droplets or streaks of water that form on the inside of a wine glass as you swirl the wine around. It is suggested that wine legs can be a visual indication of how much alcohol is in a wine. The wine legs were once thought to be associated with a wine's quality: the more wine legs, the higher the quality. However, the wine legs have more to do with physics, the wine's surface tension, and alcohol content, than perceived quality.
A Bit of Science
Wine is a mixture of ethanol and water. For simplicity, I am going to refer to ethanol as alcohol in this article. These two elements are responsible for a wine's legs when they are exposed to air. When wine is not exposed to air, there is no evaporation happening. Without evaporation, no wine legs will form in the glass.
Water has a higher surface tension, and the alcohol has a higher evaporation rate, effectively forcing the alcohol to evaporate at a faster rate. This allows the water's surface tension and concentration to increase, pushing the wine legs up the glass until the surface tension drives the water into beads. Finally, gravity forces the liquid to tear down the glass in a well-defined streak.
Marangoni Effect: This Marangoni effect refers to a scientific phenomenon that is the result of fluid surface tension caused by the evaporation of alcohol. This effect was first described in the 1860s by an Italian physicist Carlo Giuseppe Matteo Marangoni who investigated the spreading of oil drops on a water surface.
For example, if you were to warm the wine glass with your hands to heat the wine, the wine film on the side of the glass will be richer in water than it originally started out with. Why because the alcohol has evaporated away more quickly. Since the water has a higher surface tension it tends to pull the wine up into a bead. You will see a circular shape appear higher up in the glass as the film coats the glass. As more and more alcohol evaporates, more water will get pulled up to the top of the film, and eventually, there is so much water on the top of the glass’s film that it forms a wine leg – a rivulet – and the water beads down in the wine glass.
How to Examine Wine Legs
To observe wine legs in a glass, pour yourself a glass of wine.
Gently swirl your glass to distribute the wine on the inside. You will see that the film quickly forms these channels – rivulets are the technical term.
Hold your wine glass at a 45-degree angle.
Let the wine flow up one side of the glass and then level the glass.
Look at how the wine flows. This flow may help you determine the relative sweetness of the wine. A slower flow downward in the glass typically indicates a sweeter wine. Another term that is often used by the wine industry when talking about wine flow is viscosity.
Examine the density of the wine legs that form. It is suggested that the appearance of a lot of wine legs indicates that the wine may have a higher alcohol content.
What Do Wine Legs Tell Us?
Wine legs do not provide any indication of the wine's quality. The wine legs are a scientific phenomenon that may provide some information on the level of alcohol in the wine. Some wine enthusiasts think that wine legs relate to the quality, sweetness, or viscosity in the wine. They really do not. It can help you better assess a wine if you do not have access to the bottle’s wine label to provide you with this information. All this information is readily available on our modern wine labels.
Here are some generalities that may help:-
Wines with higher alcohol levels will collect a higher density of wine droplets on the sides of the glass than lower alcohol wines.
The viscosity (wine flow) of sweeter wines is much higher. The wine legs will flow more slowly down the sides of a glass with a sweeter wine.
Both the temperature and humidity of a room will greatly affect the rate at which wine legs form. If you were to examine the wine legs of the same wine in different seasons, you should be able to see a difference.
Here are some other common names used to refer to “wine legs”:-
Tears of wine. This phrase is most commonly used by the French.
Marangoni Effect: This effect refers to a scientific phenomenon that is the result of fluid surface tension caused by the evaporation of alcohol.
Church or monastery windows.
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