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Good wine leaves a thick film and heavy tears

The other side of my family is Portuguese and those guys know their wine inside out: no drunkenness but everyday a small glass (75 ml) with lunch and a bigger glass (175) with dinner.

One of the ways they judge a wine is to tilt the glass to see if it leaves a film with heavy tears. And the longer the tears take to develop, the better the wine.

I’m pretty sure this is a good test for Douro but what about other wines from further north?

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Hmm, So they are just assessing the glycerol content of the wine then??
As Glycerol is a by product of fermentation and adds some favourable qualities to wine in terms of body and texture, not all wines are made with the intention of retaining high Glycerol content and the strain of yeasts used also impact it greatly. Therefore glycerol content should not be solely used as an overall indicator of quality .


It’s perennially bemusing how frequently the “tears” feature in some sort of punt at quality / alcohol content during entry-level guided tours and tasting. I’ve given up saying anything as it just produces scowls of disapproval… and short measures.


Since I am a biochemist, and since we routinely add it to our assay mixtures, I’m very familiar with its behavior. I had therefore suspected that the film was glycerol but I had not looked into it.

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I can see how that can teach one to stay quiet. :rofl:


Although I am a wine novice and I had noticed a loose correlation between the tears and my perception of the quality/enjoyment of the flavor. It is definitely a LOOSE correlation and perhaps it only applied to the heavy fruity wines that my naive pallet appreciates at the moment.

BTW, I switched from whiskey to wine a couple of years ago and I find that it is much less physically addictive. If I drank whiskey 4 or 5 days in a row, I would become irritable owing to withdrawal symptoms. Wine and beer does not seem to have that effect. Maybe its because I’m Scottish. :frowning:

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The most reliable sources (my judgment call) say the tears are caused by alcohol - ethanol. I’m not saying Wikipedia is universally authoritative, but if you are interested in authority you can check the references


Ethanol is not specifically mentioned in the article (although it might be implied…). Is glycerol not an alcohol also?

Good point, glycerol has three -OH groups vs ethanol’s one. Glycerol therefore out-alcohols alcohol! I wonder how the islamic scholars interpret the meaning of alcohol. Perhaps the book refers to ‘intoxicating liquor’, which seems to be the phrase favored by the jurists.

In the old days it was not uncommon for chemists to taste their compounds as a primitive type of bio-assay. I therefore remember the sweet taste of glycerol quite well.

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But wait, on rereading Steve’s Wiki posting I see a further clue. Ethanol has a lower surface tension than water. According to Google the surface tensions are

water, 72 mN/m
glycerol, 63.4 mN/m
ethanol, 22.1

The tears may therefore be caused by drops of ethanol running down a film of glycerol. It would not be beyond the abilities of my lab to sip one of those drops but, to be honest, a definitive answer will spoil the mystery of the experience.

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Yes, I saw those surface tensions, too. Quite interesting that water has one of the highest of any liquid.

As you said, I think it is clearly implied, and there is around 10 times more ethanol than glycerol in wine, which is typically under 10 g/li. You also see legs in whisky, and the only discussion I can find of glycerol in relation to whisky is in terms of adulteration.

Glycerol is also often talked about in relation to viscosity, but according to Jackson’s book “Wine Tasting”, it only has a perceptible effect at over 25 g/li, as it might have in wines affected by noble rot.

To return to your orginal post, I think until the late 20th century, high alcohol contents were generally associated with quality, perhaps because they were the product of ripe grapes (before Chaptalisation at least), but also because alcoholic wines kept better.

That could well be the reason that legs are still thought to be a good sign by some. Not that they knew legs were caused by alcohol, but because they noted the correlation between legs and good wine.

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I’ve had some pretty good wine from the Society that did not have tears, which was why I raise the issue in the first place. For example, my current bottle of Lynch Bages 2005 has modest film and tears. Thus, it’s clear that not all good wine has heavy tears. Perhaps the lack of tears is simply an old fashioned indicator of low quality wine.


A friend offered me a wee dram and allowed me chooses from 18 opened different bottles all opened. People had given him the bottles on different occassions.