Carbonation primer, please

[Fat Guy]

A couple of times over the past month I've been told that pouring a carbonated beverage over ice makes the beverage flat. It does seem that when you pour a room-temperature carbonated beverage over ice it greatly decreases the carbonation. Why?

This leads me to request a primer on carbonation. I just have no clue, I realize, how it all works. I assume there are others in the same boat.

[avaserfi]

A couple of times over the past month I've been told that pouring a carbonated beverage over ice makes the beverage flat. It does seem that when you pour a room-temperature carbonated beverage over ice it greatly decreases the carbonation. Why?

This leads me to request a primer on carbonation. I just have no clue, I realize, how it all works. I assume there are others in the same boat.

There are two reasons that I know of (at least I think I know):

1) Co2 dissolves into liquids more readily at cold temperatures. So, if you take an unopened room-temperature carbonated beverage and open it, more Co2 will escape when the pressure is released.

2) Nucleation points (imperfections that Co2 has access to) encourage vigorous bubbling. Ice is full of various imperfections which act as nucleation points causing the Co2 dissolve out of the liquid.

What else did you want to know?

Edited September 25, 2011 by avaserfi (log)

[Lisa Shock]

The pouring action itself causes some loss, regardless of temperature.

That said, one of the first things I learned when I got a shave-ice machine was to use a really big cup if I was going to add a carbonated beverage to the shaved ice. Once the drink hits the ice, no matter how gently you slide the liquid in, it foams up quickly -taking up a large volume of space. Shave-ice has a lot more nucleation points than an equal weight of ice cubes because the surface area is vastly greater.

[dougal]

... It does seem that when you pour a room-temperature carbonated beverage over ice it greatly decreases the carbonation. Why?

...

If you have gas that is dissolved but shouldn't be (its over (or super) saturated), all you need to release it back to being undissolved gas is a nucleation site where bubbles can form.

By having the 'carbonated beverage' at room temperature, you are making it more super-saturated.

The colder it is, the more gas it can hold dissolved, the warmer the less gas.

Take away points: cool your drink before you open and pour it. Don't rely on pouring it over ice to do the cooling - apart from gassing off lots of carbonation, you'll be melting excessive ice which dilutes/waters down the carefully-formulated drink.