Pouring a nitro stout with the two part pour at home or a bar
Nitro stout looks wonderful when it is poured right: a cascade of tiny bubbles settling into a tight, creamy head. It takes a slightly different pour on draught and at home. Here is how to get it right.
What nitrogen does to a stout
Most beers are carbonated with carbon dioxide alone, at around 2.2 to 2.7 volumes. Nitro stout carries much less carbon dioxide, often around 1.2 volumes, plus nitrogen. On draught it is pushed with a gas blend of roughly 70 to 75% nitrogen and the rest carbon dioxide.
Nitrogen dissolves poorly in beer, so when it is forced out it forms tiny bubbles. Those bubbles make the creamy, dense head and the smooth, soft texture that nitro stouts are known for. With less carbon dioxide there is less sharp bite, so roast flavours taste rounder. Our guide on CO2 versus mixed gas for draught stout covers the gas side.
The tap is part of the trick
A nitro tap, often called a stout faucet, has a small disc with tiny holes called a restrictor plate. Beer forced through those holes is agitated hard, knocking nitrogen out of solution as fine bubbles. That is what creates the surge, the cloud of bubbles that rolls down the glass and settles upward.
Because the tap does so much work, the pour needs to give the surge time to finish. Rush it and you get a glass of beer with a shallow, loose head. Pour too slowly and the beer can warm and lose its texture.
The two part pour on draught
- Start with a clean, dry or lightly rinsed glass, usually a tulip shaped pint glass.
- Hold it at about 45 degrees under the tap with the spout near the inside wall.
- Open the tap fully and pour until the glass is about three quarters full, straightening it as you go.
- Set the glass down and let the surge settle. It takes about a minute or two for the dark beer to clear beneath a pale head.
- Top up by pouring gently into the centre until the head domes just above the rim.
The pause is the whole point. It lets the nitrogen bubbles rise and pack together before the final top up tightens the head.
Pouring a widget can at home
Many nitro stouts in cans contain a widget, a small plastic capsule filled with pressurised gas. When you open the can, the pressure drops and the widget releases a jet of gas into the beer, which starts the same kind of surge a stout tap creates.
The home pour is the opposite of the draught one. Chill the can well, to about 6 to 8 °C. Open it and turn it fully upside down into a clean glass held upright, in one smooth motion, letting the beer pour hard. Do not tilt the glass. Then wait for the surge to settle. A gentle pour wastes the widget and leaves a thin head.
Nitro cans without a widget
Some nitro beers come in cans without a widget and carry instructions for a hard pour. Read the can. If it says to pour hard, invert it quickly into the glass and let the beer foam. If it says nothing, treat it like a normal beer and pour at an angle.
Do not shake a nitro can to make it foam. That only produces a mess and a beer that tastes flat once the foam goes. The widget or the hard pour does the job when you follow the label.
Temperature and freshness
Nitro stouts are usually served a little warmer than lager, around 6 to 8 °C, so roast and chocolate notes come through. Too cold and the beer tastes thin. Too warm and the head loosens. In an Indian summer, a can left out on the table warms fast, so pour soon after opening and drink at a gentle pace.
Fresh is better. A stout at 4 to 5% ABV does not age like an imperial stout. Its texture and roast fade over months, especially if stored warm. Buy cans that have been kept chilled in the shop and store them in the fridge.
Reading the glass
A good nitro pour has a head of about one and a half to two centimetres, tight enough to hold its shape and pale cream in colour. The body underneath should be dark and settled, with no large bubbles. As you drink, the head should leave lacing down the glass.
A big, loose head, a thin cap that disappears or large bubbles in the body suggest a rushed pour, the wrong gas or a dirty glass. Tasting with that in mind is a good exercise in reading what the glass is telling you before you sip.
Try both pours side by side
If you can find a nitro stout on draught, watch the bartender's pause and count the seconds. At home, pour one widget can the right way and a second can gently at an angle into another glass. Taste both. The difference in texture will show you what nitrogen does better than any explanation.
Common questions
Why does nitro stout need a two part pour?
The first pour starts the surge of tiny nitrogen bubbles. The pause lets the head settle and the top up tightens it into a dense cap.
How do you pour a nitro stout from a widget can?
Chill the can, open it and turn it fully upside down into an upright glass in one smooth motion, then let the surge settle.
What gas is used for nitro stout?
On draught it is usually a blend of roughly 70 to 75% nitrogen with the rest carbon dioxide.
What temperature should nitro stout be served at?
Around 6 to 8 °C, slightly warmer than most lagers, so the roast flavours come through.
