[neilep (OP)]

Dearest Ewe Lot,

As a sheep, I of course am not an alcy !....and so I am of course  fascinated by the nature of champagne bubbles !!

See this glass of bubbly ?



champagne glass-759697.JPG (21.77 kB . 353x400 - viewed 16515 times)

It's difficult to see but there are streams of bubbles coming from a singularity (lol...that the trekker in me displaying itself)....One thing I also tried when in the company of someone drinking a glass was to stir it and yet still the bubbles came from the same spot !.....why is this ?..what is happening that makes bubbles come from the same spot ?.(is it a flaw in the glass ?)..........why that place and not a millimeter to the left ?..or below/above ?....what's happening there ?


Help me understand so that next time I am in the company of somebody drinking a glass of bubbly I can woo and astonish them with my repartee and wit about the nature of bubbly bubbles !!


Thanks


Neil
Bubbles In The Bath Maker


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[HellFrozenOver]

Im just guessing here.. But maybe its because of centripetal force? When you stir it it kinda has a small current and that pushes the nucleation sites to the middle.. And if you didnt stir it, when you poured it would have swirled around anyway so its pretty much the same thing..

Correct me if in wrong..

[neilep (OP)]

Im just guessing here.. But maybe its because of centripetal force? When you stir it it kinda has a small current and that pushes the nucleation sites to the middle.. And if you didnt stir it, when you poured it would have swirled around anyway so its pretty much the same thing..

Correct me if in wrong..

Thank Ewe HellFrozenOver

.....I would correct ewe if I knew if ewe were wrong or not.

I would like to know why the bubbles do originate from a singular location though and not just haphazardly all over ! Hopefully a Frenchy will pop in and answer.

[RD]

Stephen Fry on Qi, Re: bubbles in champagne:-
"No, what it is, is . . . In absolutely pure . . . say, pure distilled water, er, the exact amount of carbon dioxide, that, say, produces the supposed quarter of a billion bubbles per bottle of champagne, would just dissolve invisibly in the water. But the impurities in . . . from the glass: bits of dirt; any flake . . . like . . . like . . . like a . . . you know, a pearl from an oyster . . . it needs that, and it's called a "condensation nucleus". And about those tiny, invisible specks, each bubble just forms."

http://www.freewebs.com/qitranscripts/310.htm

A microscopic fragment of grape is more likely than "dirt", a flaw in the glass would also suffice.

[neilep (OP)]

Stephen Fry on Qi, Re: bubbles in champagne:-
"No, what it is, is . . . In absolutely pure . . . say, pure distilled water, er, the exact amount of carbon dioxide, that, say, produces the supposed quarter of a billion bubbles per bottle of champagne, would just dissolve invisibly in the water. But the impurities in . . . from the glass: bits of dirt; any flake . . . like . . . like . . . like a . . . you know, a pearl from an oyster . . . it needs that, and it's called a "condensation nucleus". And about those tiny, invisible specks, each bubble just forms."

http://www.freewebs.com/qitranscripts/310.htm

A microscopic fragment of grape is more likely than "dirt", a flaw in the glass would also suffice.

AWESOME RD ..thank ewe !

..and thanks for some QI Transcript goodness too !!

[chris]

Hi Neil

this is all about surface tension and bubble nucleation. Water is a very sticky molecule because it forms electrical interactions between adjacent molecules called hydrogen bonds. This makes it very difficult for a nascent (newly forming) bubble to prise the water molecules apart sufficiently to allow the bubble to remain in existence. This collapsing force is the surface tension.

This means that bubble formation will tend to occur where there is naturally already an imperfection in the way the molecules of liquid are interacting with each other. So a slightly rough or sharp region of the glass wall in a champagne flute for example. Here the bubbles find it slightly easier to form, so they originate at this point preferentially. Once a small bubble has formed then gas can move out of the drink very readily to join and swell the newly formed bubble, which rises to the surface and pops.

Chris

[that mad man]

As stated already its mainly due to minute particles of dust etc. stuck to the glass and sometimes due to imperfections in the glass that cause the bubbles to stream. Mainly the former as glass tends to have a fairly smooth regular tough finish.

A friend who works in a pub says its forbidden to pour beer and fizzy drinks into wet glasses as it stops most bubbles from forming and stops beer getting a head.

Try it yourself and pour a fizzy drink into a freshly washed wet glass and see the lack of bubbles.

[neilep (OP)]

Hi Neil

this is all about surface tension and bubble nucleation. Water is a very sticky molecule because it forms electrical interactions between adjacent molecules called hydrogen bonds. This makes it very difficult for a nascent (newly forming) bubble to prise the water molecules apart sufficiently to allow the bubble to remain in existence. This collapsing force is the surface tension.

This means that bubble formation will tend to occur where there is naturally already an imperfection in the way the molecules of liquid are interacting with each other. So a slightly rough or sharp region of the glass wall in a champagne flute for example. Here the bubbles find it slightly easier to form, so they originate at this point preferentially. Once a small bubble has formed then gas can move out of the drink very readily to join and swell the newly formed bubble, which rises to the surface and pops.

Chris

FANTASTIC !!.....Thank you very much Chris

Do you think this means that should a perfectly smooth surfaced glass be used (if one exists)..that there would then be no medium for the gas bubbles to form and therefore the champagne would never go flat ?

[neilep (OP)]

As stated already its mainly due to minute particles of dust etc. stuck to the glass and sometimes due to imperfections in the glass that cause the bubbles to stream. Mainly the former as glass tends to have a fairly smooth regular tough finish.

A friend who works in a pub says its forbidden to pour beer and fizzy drinks into wet glasses as it stops most bubbles from forming and stops beer getting a head.

Try it yourself and pour a fizzy drink into a freshly washed wet glass and see the lack of bubbles.

Thank You very much that mad man ......yes ..yes I will try it !

.....though I think I have experienced the very phenomena you describe when it comes to re-filling an iced filled glass with a fizzy drink !

There is usually less foam produced and by your explanation I deduce that it's because the rough edges of the ice have diminished into smooth ice cubes......whajafink ?

[that mad man]

Ah, you got me on that one.  []

[chris]

Hi Neil

yes, I would expect a perfectly smooth glass to de-gas slightly more slowly, although the drink would still "flatten" because the surface of the liquid is open to the air. This would allow steady equilibration of the dissolved gas in the drink with the room air. That is, there would be a net movement of CO2 away from the drink (where it is abundant) into the room air, where the concentration is very low.

There would also be a net movement of oxygen from the room air into the drink, which would make the drink "go off" by contributing to oxidation of the ethanol (alcohol) to ethanoic acid (vinegar)!

So the best advice is to drink up; and then get a refill (in a dry glass of course!).

Chris

[paul.fr]

As stated already its mainly due to minute particles of dust etc. stuck to the glass and sometimes due to imperfections in the glass that cause the bubbles to stream. Mainly the former as glass tends to have a fairly smooth regular tough finish.

A friend who works in a pub says its forbidden to pour beer and fizzy drinks into wet glasses as it stops most bubbles from forming and stops beer getting a head.

Try it yourself and pour a fizzy drink into a freshly washed wet glass and see the lack of bubbles.

Spot on Bee, this is also why you should use dry ice cubes and not wet ones.

[chris]

Dry ice - frozen CO2 ? - boy that will produce one cold drink (-60C)!

[paul.fr]

Dry ice - frozen CO2 ? - boy that will produce one cold drink (-60C)!

Sorry. Wet ice being that the ice cubes have started to melt, and dry ice being ice straight from the freezer that has not yet started to melt. Heck, you all know i never make sense...

[Make it Lady]

Neil have you tried putting 2 or 3 raisins into a freshly opened bottle of lemonade. The bubbles form really quickly on a wrinkled surface as there are even more imperfections. The bubbles stay in the wrinkles giving them a little life vest so they rise to the top. At the top of the lemonade the bubbles escape and the raisin sinks down to the bottom again. This is why you should never throw your granny into a fizzy drink.

When I was a student, I worked in a pub. The worst drink to make was a guiness shandy. When you added the guiness to the lemonade it would froth up and overflow. I discovered that if I stirred the lemonade before putting the guiness in it didn't fizz up like mad. How does this work?

[Bored chemist]

Stirring the lemonade knocks most of the bubbles out of it. BTW, did you know that the only reason I have ever heard of for ordering a Guinness shandy was to wind up the bar staff?

"Dry ice - frozen CO2 ? - boy that will produce one cold drink (-60C)!"
Where are you? Because at 1 bar pressure, the equilibrium temperature of dry ice is about -78C.
Are you in a pressure chamber somewhere?

[Make it Lady]

Stirring the lemonade knocks most of the bubbles out of it. BTW, did you know that the only reason I have ever heard of for ordering a Guinness shandy was to wind up the bar staff?

No this was a regular who always drank it. Even if the landlord served her, she still ordered it.

Chris has the bends!