Nitrogen is an element most often found in beer in its gaseous form (N₂) or as a constituent of larger molecules, such as proteins, amino acids, and nucleotides.

In its gaseous state, nitrogen is important to brewers as a plentiful and inert gas (N₂ makes up 78% of the atmosphere). N₂ is often used to purge vessels or packages of unwanted oxygen in applications varying from purging a brew kettle to avoid hot-side aeration to purging packages of hops for storage. Also, N₂ is used as an ingredient in nitrogenated beers, where it adds no flavor but produces very fine, stable bubbles (in comparison to N₂, carbon dioxide produces relatively large bubbles with a tart, acidic flavor). See nitrogenated beer. N₂ is usually separated from other atmospheric gasses using a nitrogen generator; the nitrogen can then be used immediately in its gaseous state or liquified for later use.

N₂ in its liquid state (LN₂), which at atmospheric pressure is between –195.8°C and –210°C (–320.8°F and –410°F), can be useful to brewers as a refrigerant for the cryogenic storage of yeast cells. Also, LN₂ can be dripped into bottles or cans before they are filled with beer. In this application, the LN₂ rapidly evaporates upon hitting the bottom of the package and subsequently purges the package of unwanted air.

In bars and restaurants, nitrogen is often part of a gas blend (with CO₂) used to drive draught systems. At normal draught system operating pressures, nitrogen is far less soluble in beer than CO₂ and therefore can be used to help push beer to the tap without concern about dissolution of nitrogen into the beer. The proper ratio of nitrogen to CO₂ will depend on temperature, pressure, and the desired carbonation level of the beer. It is worth noting that nitrogen pressure will not hold CO₂ in beer. Many draught systems that run on a gas blend containing 75% nitrogen, a blend meant for the dispense of Irish stout, will end up serving flat beer as a result.

See also free amino nitrogen (fan).