carbonation
Nitrogenation
Dissolve nitrogen alongside a low level of CO₂ so the beer pours with a dense creamy head and drinks soft rather than sharp.
What is actually happening
- Charged with nitrogen, low on CO₂. The beer carries mostly nitrogen with much less carbon dioxide than a normal keg. Carbonic acid is what makes beer taste sharp, so less of it is why nitro drinks rounder and softer, flattering roast and malt while muting hop aroma.
- Forced through a restrictor plate. The tap ends in a disc drilled with small holes. Pushing the beer through it at pressure shears the gas out of solution as very fine bubbles — this is the part doing the work, not the glass and not the pour.
- The cascade, then a tight head. Nitrogen is far less soluble than CO₂, so it leaves solution immediately rather than gradually. The visible surge is that happening, and the dense persistent head is what it leaves behind.
Nitrogen is far less soluble in beer than carbon dioxide, so most of it comes out of solution immediately on dispense as very fine bubbles — which is what produces the cascading surge and the tight, persistent head.
Because carbonic acid contributes perceived sharpness and there is much less CO₂ present, nitro beer tastes fuller, rounder and less bitter than the same beer on CO₂. It flatters roast and malt and tends to mute hop aroma.
Styles where this step is decisive
- Dry stout
Sharp roasted-barley bitterness over a light body and a very dry finish — much lighter to drink than its colour suggests.
- Irish extra stout
A stronger, fuller dry stout with more malt depth and body while keeping the sharp roasted-barley character.
- Sweet stout
A stout sweetened with lactose, giving chocolate and cream character over a full body and gentle roast.
- Alcohol-free stout
An alcohol-free dark beer where roasted grain does most of the work — one of the more successful conversions in the category.
Related steps and concepts
- Force carbonation — The conventional approach.
- Nitro — The dispense vocabulary.
Also at the carbonation stage
Bottle conditioning · Force carbonation · Krausening · Priming
See the whole process in order on how beer is made.
Last reviewed 2026-08-16.
Evidence
What BeerHQ knows about this, and how. Every statement carries the state of the evidence behind it rather than being presented flatly as fact.
Dissolved carbon dioxide forms carbonic acid, which contributes perceived sharpness and bite, so a nitrogenated beer with much less CO₂ tastes softer and less bitter than the same beer on carbon dioxide.
Backed by a source
Source: Beer: Tap into the Art and Science of Brewing — print
Nitrogen dispense was developed in the late 1950s to give keg stout the soft texture and dense head of a well-kept cask beer, and remains most associated with dry stout for that reason.
Backed by a source
Sources: The Oxford Companion to Beer — print; Beer: The Story of the Pint — print
Nitrogen is far less soluble in beer than carbon dioxide, so most of it leaves solution immediately on dispense as very fine bubbles — which is what produces the cascading surge and dense head of a nitro pour.
Backed by a source
Sources: Brewing: Science and Practice — print; Institute of Brewing & Distilling technical publications