...I'm not only talking about the initial burst of CO2 usuall
ountered, but how much PSI does the fermentation process produce though
out it's life. ...
hi.
This is a tricky question, and the correct answer is that it depends on how
deep do you put the outlet of the bottle under water. If the outlet is open
to the atmosphere, then the relative pressure of the fermetation process is
0 psi. This is because as soon as the yeast generate the CO2 and let it
bubble out of the solution, it escape to the atomsphere, and does nothing to
the internal pressure. If the inlet is a few inch below the water, then the
pressure will be determine by the depth of discharge (convert inch_H2O to
psi).

If the outlet opening is constricted (via a needle valve, etc.), then the
relative pressure will depends on the size of the opening as well as the
rate (volume per hour) of CO2 generation.

I can't think of anything that relate the relate pressure (not in a closed
container, as you said above regarding the "initial burst".) to the volume
of the container.
bye -ck-