01
Already carbonated drinks
Beer refills, cider and mixed drinks served or stored from a keg.
iKegger Guide
Carbonation Guide: Force Carbonating, Pressure Brewing & Storing Drinks
This guide explains how CO₂ pressure, temperature and time affect carbonation when storing, serving or carbonating drinks in a keg.
Applies to
Find the right pressure setup for kegged drinks, homebrew and pressure fermentation.
Start with the drink type below, then use the pressure and temperature guide to set your keg correctly.
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Homebrewed beer
Flat beer that needs controlled carbonation before serving.
03
Soda & mixed drinks
Soda water, rum and coke, cocktails and other higher-carbonation drinks.
04
Pressure-fermented beer
Beer carbonated during fermentation with a spunding valve.
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Mini kegs & growlers
iKegger mini kegs, growlers and other pressurised vessels.
Quick Start
What pressure should I use?
For many beers stored cold in a fridge, a good starting point is around 9–13 PSI at 5 °C. The correct pressure always depends on the drink temperature and the carbonation level you want.
| Drink / use case | Typical pressure or range |
|---|---|
| Most beers at 5 °C | 9–13 PSI |
| Lagers, ales and amber beers | around 2.5 volumes CO₂ |
| Soda water and mixers | higher carbonation, orange range in the chart |
| Pressure fermentation at 24 °C | around 29 PSI for beer carbonation |
CO₂ Basics
Why carbonation depends on temperature and pressure
Carbonation is the process of dissolving CO₂ into liquid. In a keg, the liquid absorbs CO₂ from the gas space above it.
Colder liquid absorbs more CO₂
Cold liquid absorbs CO₂ faster and keeps more CO₂ dissolved.
Higher pressure increases carbonation
Higher CO₂ pressure pushes more gas into the liquid and speeds up absorption.
More contact means faster absorption
Shaking or rolling a keg increases the contact area between liquid and gas.
Carbonation stops at balance
At a fixed temperature and pressure, the drink stops absorbing CO₂ once balance is reached.
Force carbonation
Two ways to carbonate a drink
High pressure and shaking
The fastest way to carbonate a flat drink is to chill it, apply high CO₂ pressure and shake or roll the keg.
This works because shaking increases the contact area between CO₂ and liquid, so CO₂ is absorbed faster.
Best for: quick carbonation when exact carbonation level is less important.
Main downside: it is easy to over-carbonate because the final CO₂ level is harder to control.
Set pressure and wait
The more accurate method is to choose the carbonation level you want, then store the keg at the matching temperature and pressure.
This method uses the carbonation table to match drink temperature, desired carbonation level and required CO₂ pressure.
Best for: stable, repeatable carbonation in beer, cider and mixed drinks.
With this method, the drink stops absorbing CO₂ once it reaches the correct balance.
Carbonation table
Temperature, pressure and beer style
Use the chart below to find the correct CO₂ pressure for your drink temperature and target carbonation level.
- Choose the carbonation level for your drink style. Most lagers, ales and amber beers sit around 2.5 volumes of CO₂.
- Check the temperature of the liquid. Example: your keg is stored in a fridge at 5 °C.
- Find that temperature on the left side of the table.
- Follow the row across until you reach the correct colour band for your drink style.
- Read the required CO₂ pressure from the bottom axis.
For a typical beer at 5 °C, this usually means setting the regulator to around 9–13 PSI.
Timing & serving
How long does carbonation take?
With the controlled set-and-wait method, a chilled 19 L keg usually takes about one week to carbonate.
Smaller kegs often carbonate faster, but there is no fixed time. Carbonation time depends on keg size, liquid temperature, pressure setting, headspace and whether the keg is shaken, rolled or left still.
Can I taste it during carbonation?
Yes. You can taste the drink during carbonation to check the level. Once it is carbonated enough, you can either leave the regulator attached or disconnect it until serving.
Regulator
Should I leave the regulator connected?
Yes, you can leave the regulator connected and turned on. Once the drink reaches the set carbonation level, the regulator will only add more gas when pressure drops. This usually happens when you pour liquid from the keg.
Leaving the regulator connected keeps the serving pressure and carbonation level stable. Disconnecting the regulator does not normally save gas unless there is a leak in the system.
Important note
Check valves and regulator readings
If you use a check valve, the regulator gauge may not show the actual pressure inside the keg. The gauge shows the pressure between the regulator and the check valve.
If the pressure inside the keg rises because the keg warms up, that pressure may not show on the regulator because the check valve prevents gas from flowing back.
Use a check valve when needed, especially when the keg is lying down. For accurate pressure adjustment, avoid relying on the regulator gauge alone when a check valve is installed.
Pressure fermentation
Brewing under pressure: carbonate while fermenting
Pressure fermentation allows beer to carbonate during fermentation by using the CO₂ naturally produced by the yeast.
This is useful when brewing in a pressure-capable fermenter such as a FermZilla, Fermentasaurus or King Jr.
Example: ale at 24 °C
- you ferment an ale at 24 °C
- you attach a spunding valve
- you set the spunding valve to 29 PSI
- the beer carbonates during fermentation
- once fermentation is complete, the beer is already carbonated
After fermentation, you only need to chill the beer and either attach a tap or transfer it to a keg for serving.
Why brew under pressure?
Pressure fermentation can save both time and gas. Instead of carbonating the finished beer
later with bottled CO₂, you use the CO₂ produced during fermentation.
Quick answers
Carbonation questions
What pressure should I use for most beers?
For many beers stored at around 5 °C, set the regulator to about 9–13 PSI.
Why does shaking the keg carbonate faster?
Shaking increases the contact area between liquid and CO₂, so the liquid absorbs CO₂ faster.
Can I over-carbonate with the controlled method?
At a fixed temperature and pressure, the drink stops absorbing CO₂ once it reaches balance.
Does disconnecting the regulator save gas?
Usually not. Disconnecting only saves gas if there is a leak in the system.
Pressure transfer
Transferring Under Pressure
Use pressure transfer when moving liquid from fermenter to keg or from keg to keg. This keeps the system closed and lets you move the drink with controlled pressure.
Pressure transfer steps
- Sanitise and flush your keg with CO₂ to remove any oxygen.
- Pressurise your empty keg to the same pressure as the source vessel. If you connect the two gas posts, they will equalise.
- Set your spunding valve to the same pressure. Connect it to a regulator and adjust.
- Connect the liquid posts together with 2 × liquid disconnects and some beer line.
- Attach the spunding valve to the gas post of the empty vessel.
- Attach your regulator to the gas post of the full vessel.
- Turn up the pressure on the regulator to slightly above the empty vessel pressure.
- Wait until transfer is complete.
How to measure when the keg is full
Condensation line
Watch the condensation line on the outside of the empty keg rising.
Scales
Place the empty keg on a zeroed set of scales and use the fact that 1 litre of liquid weighs 1 kg.
Flow stopper
Use a flow stopper with the spunding valve. This automatically stops the flow once the keg is full.