World Library  
Flag as Inappropriate
Email this Article

Tears of wine

Article Id: WHEBN0002906037
Reproduction Date:

Title: Tears of wine  
Author: World Heritage Encyclopedia
Language: English
Subject: Surface tension, Wine tasting, Index of physics articles (T), Oenology, Convection
Collection: Fluid Mechanics, Oenology, Wine Tasting
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Tears of wine

Tears of wine show clearly in the shadow of this glass of 13.5% Caluso Passito dessert wine

The phenomenon called tears of wine is manifested as a ring of clear liquid, near the top of a glass of wine, from which droplets continuously form and drop back into the wine. It is most readily observed in a wine which has a high alcohol content. It is also referred to as wine legs, curtains, or church windows.

Contents

  • Cause 1
  • Related phenomena 2
  • See also 3
  • References 4
  • External links 5

Cause

The effect is a consequence of the fact that alcohol has a lower surface tension than water. If alcohol is mixed with water inhomogeneously, a region with a lower concentration of alcohol will pull on the surrounding fluid more strongly than a region with a higher alcohol concentration. The result is that the liquid tends to flow away from regions with higher alcohol concentration. This can be easily and strikingly demonstrated by spreading a thin film of water on a smooth surface and then allowing a drop of alcohol to fall on the center of the film. The liquid will rush out of the region where the drop of alcohol fell.

Wine is mostly a mixture of alcohol and water, with dissolved sugars, acids, colourants and flavourants. Where the surface of the wine meets the side of the glass, capillary action makes the liquid climb the side of the glass. As it does so, both alcohol and water evaporate from the rising film, but the alcohol evaporates faster, due to its higher vapor pressure. The resulting decrease in the concentration of alcohol causes the surface tension of the liquid to increase, and this causes more liquid to be drawn up from the bulk of the wine, which has a lower surface tension because of its higher alcohol content. The wine moves up the side of the glass and forms droplets that fall back under their own weight.

The phenomenon was first correctly explained by physicist James Thomson,[1] the elder brother of Lord Kelvin, in 1855. It is an instance of what is today called the Marangoni effect[2] (or the Gibbs-Marangoni effect): the flow of liquid caused by surface tension gradients.

The effect can be used to move water droplets around in technical applications. [3]

It is sometimes claimed incorrectly that wine with "lots of legs" is sweeter or of a better quality.[4] In fact the intensity of this phenomenon depends only on alcohol content, and it can be eliminated completely by covering the wine glass (which stops the evaporation of the alcohol). British physicist C. V. Boys argues[5] that the biblical injunction

refers to this effect. Since the "tears of wine" are most noticeable in wine which has a high alcohol content, the author may be suggesting this as a way to identify wines that should be avoided in the interest of sobriety.

Related phenomena

Other fluid phenomena that arise in alcohol-water mixtures are beading and viscimetry. These are more pronounced in liquor than in wine, and both phenomena are more pronounced in stronger liquor.

Beading refers to the formation of stable bubbles when liquor is shaken. This occurs only in liquor that contains more than 46% alcohol. It is an example of the Marangoni effect. Shaking a whisky bottle to form bubbles is referred to as “beating [beading] the whisky”.

Viscimetry is the formation of whorls when water is added to a high-alcohol mixture.

See also

References

  1. ^ James Thomson (1855) "On certain curious motions observable on the surfaces of wine and other alcoholic liquours," Philosophical Magazine, 10 : 330-333.
  2. ^ Carlo Marangoni, "Sull' espansione delle gocce di un liquido gallegianti sulla superficie di altro liquido" (On the expansion of a drop of liquid floating in the surface of another liquid) (Pavia, Italy: Tipographia dei fratelli Fusi, 1865).
  3. ^ N.Y. Times, "Tiny Internal Tornadoes Bring Drops to Life" [2]
  4. ^ "'"Wine 'Legs. KitchenSavvy. 2004-12-04. Retrieved 2010-05-05. 
  5. ^ C.V. Boys, Soap Bubbles: Their Colours and Forces Which Mould Them, 2nd ed., Ch. 2, (1911).

External links

  • KitchenSavvyWine 'Legs', from
  • A video of tears of bourbon
  • Why Does Wine Cry?
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.