Nitro Cold Brew: How Nitrogen Makes Coffee Creamy, and How to Make It at Home

Nitro cold brew is cold brew coffee infused with nitrogen gas and poured from a stout-style tap, so it arrives in the glass as a cascade of tiny bubbles that settles under a creamy head. It looks like a pint of stout, tastes smooth and rich without any milk, and is served cold but without ice, which would break the foam.

The drink is cold brew plus physics. Everything distinctive about it — the cascade, the head, the texture — comes from choosing nitrogen rather than the carbon dioxide used to make drinks fizzy.

How it is made and served

It starts as ordinary cold brew: coarse coffee steeped in cold water for many hours, filtered and diluted to drinking strength. The finished coffee goes into a keg or dispensing system that infuses it with nitrogen under pressure, so that some of the gas dissolves into it.

It is poured through a stout faucet, the same kind of tap used for nitrogen-dispensed beers. As the pressurised coffee is forced out through the tap, the dissolved gas breaks out of solution as a mass of tiny bubbles. Those bubbles are what you see tumbling in the glass before they rise and gather into a dense, tan head.

Ice is left out deliberately: it would knock the foam down and dilute the coffee. Nitro cold brew is served chilled, but straight.

Why nitrogen and not carbon dioxide

Most fizzy drinks are carbonated with carbon dioxide. Coffee is not, for two reasons.

Carbon dioxide makes acid. It dissolves readily — about 1.45 g per litre of water at 25 °C and normal pressure — and a small amount of it reacts with the water to form carbonic acid, which gives sparkling water its slightly tart taste. Added to coffee, it would sharpen the flavour and make it fizzy. Nitrogen does not form an acid, and it is far less soluble.

Nitrogen makes a creamier foam. A 2022 workshop on nitro beer at the Craft Brewers Conference set out the physics, and it applies to coffee too:

• Smaller bubbles mean a thicker foam and a creamier mouthfeel. Nitrogen breaks out of solution as very fine bubbles.
• The foam lasts longer. In any foam, gas moves from small bubbles into larger ones, so big bubbles grow and pop while small ones shrink. Because carbon dioxide is much more soluble than nitrogen, it moves between bubbles faster, and a carbon dioxide head decays sooner.
• Liquid drains more slowly. Small nitrogen bubbles slow the drainage of liquid from between them, and foam stability depends on that drainage rate.

The same presentation notes that nitrogen has been shown to suppress some flavour attributes in beer, which is one reason nitro drinks taste softer and rounder. Matt Hartings, a chemistry professor at American University, told NPR in 2019 that the bubbles change the coffee's mouthfeel much as creamer does — the texture itself reads as richness.

Where it came from

Nitro cold brew appeared in American specialty coffee shops in the early 2010s, and its exact origin is disputed. It is most often credited to Cuvée Coffee in Austin, Texas, and Stumptown in Portland, Oregon, around 2013, with draught coffee served at The Queens Kickshaw in New York in 2011 a possible predecessor. By 2015 Stumptown and Cuvée were selling it in cans fitted with a nitrogen-filled capsule, the same kind of widget that gives canned stout its head.

The big chains followed. Starbucks introduced nitro cold brew at 500 stores in the summer of 2016 — The Coffee Bean & Tea Leaf had already offered it in Los Angeles — and by 2020 it was available at more than half of Starbucks' US locations.

Making it at home

True nitrogen at home means equipment, but there are three routes.

The cream whipper method is the practical one. Cream whippers are charged with nitrous oxide (N2O), not nitrogen. It is a different gas: it dissolves about as readily as carbon dioxide — around 1.5 g per litre of water at 15 °C — and has a slightly sweet scent and flavour, but it does not turn the coffee tart the way carbon dioxide does. Dispensed from a whipper, it gives a creamy, cascading pour that comes close to the real thing.

1. Make and chill cold brew, diluted to the strength you like to drink.
2. Fill the whipper with the coffee, staying within the maximum fill line.
3. Charge it with one nitrous oxide cartridge, or two if the instructions allow, and shake for about 30 seconds.
4. Rest it in the fridge for a few minutes.
5. Dispense slowly, holding the whipper upside down, against the side of a tall glass, and let the cascade settle before drinking.

Use only chargers made for cream whippers and follow the manufacturer's instructions. Do not substitute carbon dioxide chargers: as with whipped cream, carbon dioxide produces bubbles but gives a sour taste.

Caffeine

Nitrogen adds no caffeine, so a nitro cold brew has whatever its cold brew has — and cold brew is not a weak drink. In a 2017 study in Scientific Reports, coarse-ground cold brew measured substantially higher in caffeine than hot-brewed coffee made at the same coffee-to-water ratio. How strong your glass is depends mostly on how much the concentrate was diluted. The cold brew guide covers ratios and caffeine in detail, and the caffeine guide compares other drinks.

For a creamy topping on ordinary cold brew without any gas, see the cold foam guide.