Pouring fizzy pop from a bottle

[Harry Bloomfield]

We don't drink much, but buy in large bottles 1.25 to 2L. Towards the end the contents is always pretty flat. That due to each time the bottle cap is taken off, pressure is lost before any can be poured.

I'm think if it could be poured from the bottom, much less pressure would be lost with each pour if only the cap allowed that. Out of curiosity, I am experimenting with a 2L bottle of Coke, by inverting it then loosening the cap just enough to blow a glass at a time out.

Half empty now, but there is still lots of pressure, but might there be a better way?

[critcher]

are you real?

[Chris Hogg]

[harry]

Commercial devices are available to do this in effect.

[Harry Bloomfield]

critcher brought next idea :

Of course. I see a problem, I seek out solutions.

[Andy Burns]

You want a 'bottle' with a dip-tube, aka a corny keg

Then you'll need a CO2 bottle to charge it, you could start buying the postmix syrups, fit your own 'snake' so you've got coke/lemonade/fanta at the push of a button :-)

[newshound]

is the first one that I get from that tinyurl and covers what I would have said. Keep it in the fridge is the easy one.

[Andy Burns]

Are you referring to the fizzkeeper?

How would pumping air into the bottle help? Each gas has its own partial pressure in the bottle, so adding (mainly) N and O won't stop the CO2 coming out of solution.

[Fredxxx]

Not very helpful are we?

[Harry Bloomfield]

Andy Burns formulated on Sunday :

It is kept in the fridge anyway. I agree that the Fizzkeeper would not work that well.

[damduck-egg]

Keep it simple, purchase smaller bottles.

Your consumption is not enough to let the product remain in optimal condition, you can argue that the larger size is saving you money but that is because so far you have accepted that to do so you have tolerated a product that is past its best. You can do that because such a product is still relatively harmless to consume but you would you do it with milk that is not so robust?

Any gadgets or other tricks is just faffing about to satisfy your desire to tinker or do you really need to save every penny on a luxury consumable.

G.Harman

[Chris Hogg]

Your mention of partial pressure reminds me of a technique I saw described many years ago for keeping fizz fizzy. After you've poured out what you want, squeeze the bottle to push out all the air and bring the liquid surface up to the top of the neck, then replace the cap tightly. The theory is that the amount of CO2 that remains in the fizz is proportional to the partial pressure of CO2 in the gas above the liquid surface (Henry's Law

). When the bottle is half full, the partial pressure of CO2 in the air-space is reduced because of the partial pressures of O2 and N2 from the air, as you say. Expelling all the air allows only CO2 to exist in that space, so the fizz will still have a lot of CO2 dissolved in it and remain fizzy.

I must admit I remain a bit sceptical, but the OP can at least try it, even if it does mean the squashed bottles look a bit odd.

Or, as someone else suggested, just pay a bit more and get smaller bottles.

[Harry Bloomfield]

[e-mail] pretended :

Absolutely not about money, I just have an extremely enquiring mind. The bottle I opened mid last week, still tastes fine, through the tricky process of inverting it to pour it. I suspect part of the problem is air getting in and it cannot get in if the gas pressure is used to blow the liquid out.

[Bob Eager]

Mentioned in the link above. Personally I buy cans in bulk.

[Harry Bloomfield]

on 29/05/2017, Chris Hog supposed :

Some means would need to be found, to prevent the bottle expanding again due to gas pressure. It has the disadvantage that when the top is opened, CO2 will be lost and replaced with air.

My rather messy method of inverting the bottle, prevents any CO2 escaping, apart from that which comes out with the liquid, and absolutely no air can get in.

[Fredxxx]

I believe your explanation is half correct.

The amount of CO2 is constant, before any leakage, so the partial pressure in the drink and air-space will be the same independent of whether there is additional air in the bottle.

What you might have missed is the absolute pressure will rise further due to the present of air in the space above the fluid by nearly an atmosphere more than if the bottle was fully collapsed with no air space above the drink.

PET might be impervious to water and water vapour I don't believe it is to air and CO2 so the bottle with the higher pressure will loose more gas.

BICBW

[Harry Bloomfield]

Harry Bloomfield expressed precisely :

The method works very well indeed, better than I expected apart from the mess it caused. There is just a cupful left in the 2L bottle, the bottle is still firm with pressure and plenty of gas is evident when I pour - I just need to find a better way to pour than loosening the cap with the bottle inverted. I wonder if one of those caps often sold with bottled drinking water might work, where you just pull to open?

[damduck-egg]

Put the Term "Fizzy Drinks saver" into a search Engine, it won't be long before you find a gadget designed for the task available on ebay for a couple of pounds. Holds the bottle upside down and a connection to a flip tap . You could probably DIY one from the pictures but remember soft drinks can be quite aggressive on materials used.

G.Harman

[Harry Bloomfield]

[e-mail] explained on 31/05/2017 :

Thanks for that - yes I found such a gadget straight away on Ebay, which uses exactly the same idea as I suggested, of inverting the bottle so no gas is lost in the opening of the bottle.