Natural carbonation occurs during the fermentation process, when yeast consumes sugar, producing carbon dioxide.
Carbonation stimulates something called the trigeminal nerve found in your mouth. The purpose of the trigeminal nerve is to sense hotness, coldness, or irritants.
Carbonation can have a noticeable impact on beer flavor. By stirring volatile aroma compounds in the beer, carbonation helps make them more detectable.
Inside the fermentation vessel, the carbon dioxide has nowhere to escape, so it saturates the beer and transforms into carbonic acid (the liquid form of CO2). That carbonic acid then binds to the flavor and aroma compounds in the beer.
Nowadays, it is relatively uncommon to carbonate an entire keg naturally. However, the process is possible and uncomplicated.
Here are some of the reasons why you might choose natural carbonation: - Natural carbonation requires less equipment than forced carbonation. - Homebrewers who prefer natural carbonation over forced carbonation say the natural carbonation results in a thicker head, smaller bubbles, and more lacing
While it is possible to keg beer without a carbon dioxide setup, beer served without it will spoil much more quickly.