How are the bubbles in beer formed?

Bubbles are an essential part to your beer drinking experience and now that pubs and restaurants have opened their doors again, what better time to learn about how or why they are there? The answer to all of this is carbon dioxide (CO2)!

Why is CO2 in beer in the first place?

CO2 is needed for the carbonation of beer which gives the popular beverage its distinctive element of bubbles. Carbonation, put simply, is carbon dioxide gas dissolved in liquid. Beer can be carbonated in two ways, naturally or forced.

Natural Carbonation

Natural carbonation is the result of the fermentation process. CO2 and alcohol is produced during this stage when the yeast digests the sugar in the wort. Most of the carbon dioxide gas escapes during this stage, however in order for the beer to stay naturally carbonated, the brewer will seal the beer in a container just before fermentation is complete.

The beer is now naturally carbonated meaning that when the pressure is released the carbon dioxide rises to escape and the bubbles are formed!

Forced Carbonation

In order to force carbonation, the brewer instead leaves the beer to fully complete fermentation. Once this is finished, the beer is put into a sealed container and pumped with CO2 which will then be absorbed into the liquid. The forced carbonation method is also commonly used for kegs. The same process applies allowing fermentation to complete and pumping carbon dioxide into the keg where the gas will be absorbed into the liquid, the beer will be fully carbonated within a few days.
Although the CO2 in your beer may just seem like a small element to you, if CO2 levels are left unmonitored during the fermentation and/or forced carbonation stage, the consequences could be life threatening.

The dangers of CO2 in beer fermentation and carbonation

As already mentioned, most of the carbon dioxide gas escapes during the fermentation process which can be extremely dangerous when in a confined space. Brewing tanks tend to be stored with little space around them for the gas to escape. An increase of CO2 levels from as small as 0.5% can have implications on the human body and can start to cause effects such as headaches, drowsiness and nausea. If left undetected the effects of CO2 on the body can be life threatening. To keep brewers and any employees safe, it is highly recommended that a CO2 detector is used in breweries.

It is also recommended that CO2 sensors and alarms are used in pub and bar cellars, as this is where forced carbonation in kegs typically takes place, which are often confined spaces. Forced carbonation requires a compressed gas CO2 supply, which is regulated and piped creating a high risk for potential CO2 leaks.

If you think your brewery, bar, pub or establishment might need CO2 monitors, we have many different options available for you.

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