Beer carbonation

This page briefly explains 2 methods of carbonation and offers a tool to calculate the top pressure in CO2 required to reach the desired amount of dissolved CO2 in the beer. It also takes into account the hydrostatic pressure in the tank.

Natural carbonation

The natural and classic way to carbonate is to apply some counter pressure on the fermentation vessel before the end of the fermentation in order to increase the dissolved CO2 content. The amount of dissolved CO2 depends on the pressure and the temperature. The pressure is influenced by:

  • The top pressure built with the formed CO2 during fermentation retained by the bunging valve
  • The hydrostatic pressure in the tank.
  • The beer properties (SG, alc%, pH,..)


  • It’s cheap if the existing tanks are equipped with bunging valves that can build up enough pressure
  • A natural carbonation can give a smoother head.


  • You need to remember to set the right counter pressure at the right time of the fermentation.
  • The whole volume is then carbonated the same way.
  • The CO2 content is calculated, not measured.

The below calculator takes the hydrostatic pressure in the tank into account and the temperature.

Forced carbonation

The CO2 is injected inline with the help of an inline carbonation system. It can be equipped with an inline CO2 meter that will make sure the exact level of CO2 is dissolved.

It consists in an injection point via a static mixer or venturi system, a holding cell, a CO2 meter, a back pressure valve.


  • It’s done instantly during the transfer to the next process step.
  • It precisely Follows a set point if coming with an inline CO2 reader. No calculation to guess the content, inline reading instead.
  • Different carbonation levels can be achieved on the same tank (50% to keg filling and 50% to bottle filling)
  • Different recipes (CO2 concentrations) can be stored in the system.
  • No need for pressure tanks.


  • It’s costly
  • Extra piece of equipment means extra maintenance.