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Decarbonising Fizzy Drinks


Erina

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Assuming that carbon is the element of which makes something like Fanta or Coca Cola fizzy, is there a way to remove that is a short period of time ?

Such beverages go "flat" after being exposed to oxygen, could I therefore introduce that to achieve the same aim ?

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1 hour ago, Erina said:

Assuming that carbon is the element of which makes something like Fanta or Coca Cola fizzy, is there a way to remove that is a short period of time ?

Such beverages go "flat" after being exposed to oxygen, could I therefore introduce that to achieve the same aim ?

Stir it vigorously 

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1 hour ago, Erina said:

Assuming that carbon is the element of which makes something like Fanta or Coca Cola fizzy, is there a way to remove that is a short period of time ?

Such beverages go "flat" after being exposed to oxygen, could I therefore introduce that to achieve the same aim ?

It's not the element carbon but dissolved carbon dioxide, CO2, that makes drinks fizzy. And it's not exposure to oxygen that makes them go flat, but the reduction of pressure on exposure to the atmosphere.

When you open a bottle of fizzy drink, the pressure above the liquid drops. Since the amount of gas the water can dissolve depends on the pressure of CO2 above it, you then have a supersaturated solution, which is why it fizzes. Any nucleus for bubbles to form on will accelerate the rate at which the CO2 comes out of solution. A classic way is to put in a sugar lump. This has a large surface area with many sharp edges, which promotes the initiation of bubbles. Sand would also do the job, but not so good if you want to drink it later.

The reason why you need a nucleus to start the bubbles off is because of the energy needed to pull apart the water molecules. The excess pressure inside a bubble is 2T/r where T is the surface tension of the liquid - a measure of the strength of the intermolecular forces - and r is the radius of the bubble. From this you can see that the smaller the radius, the higher the pressure, so in the limiting case this formula predicts an infinite pressure is needed to blow up  a bubble of zero radius i.e. at the start. While this formula is not accurate at very small radii, it gives an idea of the problem. Sharp edges reduce the intermolecular forces in their vicinity, as the water molecules are not entirely surrounded by other water molecules, making it easier for gas molecules to push them apart and start off a bubble. 

 

Edited by exchemist
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2 hours ago, Erina said:

@exchemist: So then, two glasses side by side, if one had a straw inside of it then the drink would lose more CO2 faster ?

Very likely yes. The straw would provide more nuclei to initiate bubbles.

In the lab, we used to put "boiling sticks" into flasks of solvent that we wanted to boil, to make sure there were plenty of nuclei for bubbles to form evenly. The worst thing was to have glassware that was perfectly smooth and clean, because then you could get superheating and "bumping" when the superheated liquid finally found something to initiate a bubble and everything boiled over at once.

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13 minutes ago, Erina said:

Wow, cool experiment !

In the interests of speed what edible chemical could be used to decarbonise a drink in place of a straw with a lot of time on its hands ?

Sucrose, as I mentioned previously. Or NaCl but that would spoil your drink.

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Unless the NaCl is on some peanuts.  This was a drink in the southern US, to drop some peanuts into a coke, the salt washes off the peanuts right away and it fizzes intensely for a bit.  Wait a few minutes and drink, has a delicious nutty flavor and less carbonation "burn." Our family lived for about six years on the northern edge of the region where this was popular.  Be sure it's classic Coke and the peanuts are salty.  (This does NOT work with diet colas, and is probably an abomination)

Why is this in inorganic chemistry?

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The peanut idea is a good one, I'm surprised there isn't a YouTube or TikTok video that went viral on that one.

I didn't want to modify the flavour, if possible.

Feel free to move the topic if its in the wrong place.

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1 hour ago, TheVat said:

Unless the NaCl is on some peanuts.  This was a drink in the southern US, to drop some peanuts into a coke, the salt washes off the peanuts right away and it fizzes intensely for a bit.  Wait a few minutes and drink, has a delicious nutty flavor and less carbonation "burn."

I remembered reading about a tip to do this with beer, if you want to release some more of the carbonation, which allegedly affects the flavor. From back when a bowl of peanuts was commonplace at a bar.

(moved to plain old chemistry)

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11 hours ago, swansont said:

I remembered reading about a tip to do this with beer, if you want to release some more of the carbonation, which allegedly affects the flavor. From back when a bowl of peanuts was commonplace at a bar.

(moved to plain old chemistry)

Of course, the cognoscenti among us drink real ale, which has not been artificially carbonated in the first place....

Which is just as well, as I dislike roasted peanuts (though I do like the fresh ones.)

 

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