Gushing & Foaming in Naturally Carbonated Sodas... Gas Laws & Head Space

[Blue-Frog]

Is it true that the pressure measured in a bottle of soda is only head space pressure... and that the amount of dissolved CO2 has (absolutely?) no pressure contribution,
so long as it stays dissolved?

 

[VikeMan]

While it's true that the CO2 dissolved in the liquid isn't, at that very moment, affecting the pressure in the headspace, the CO2 does constantly seek equilibrium between the liquid and the headspace. At equilibrium, more total CO2 in the system means more CO2 in the liquid and more CO2 in the headspace (thus higher pressure). Less CO2 in the system means less CO2 in the liquid and less CO2 in the headspace (thus lower pressure).

 

[Blue-Frog]

So in terms of under- desired- and over-carbonation,
it is possible to have the same head pressures... if the systems have not have reached equilibrium.
How long does it take 3 bar to reach equilibrium, say at 12 C. ?
More than several days?

In my soda making adventures I have been having a problem that appears 3~5 seconds after opening. A rather persistent "snake" of foam dances out of the bottle as if hypnotized by a snake charmer. I lean toward thinking "it's not a "gushing" contaminate issue, rather an "It needs more time to go into solution" or an "I need something like gum arabic" issue.

My measurements and interpretations indicate ~3 BAR @ ~12C. giving at least 8.5g CO2/L

Any insight?