Coffee Story: Nitro Cold Brew
I was in Batu Pahat, Johor, about a month ago and visited a cafe called 9% Coffee House in the town centre. In the cafe, I ordered a "black craft coffee" from the menu. The beverage has an interesting Chinese name called "假装啤酒的咖啡", which means "coffee pretending to be beer". With a thick and creamy layer above the blackish content, it does looked like a glass of black craft beer.
The "black craft coffee" is generally known as nitro cold brew — a special cold coffee that was created in the 2010s in Texas.
When brewing a cup of espresso, a layer of crema is formed under pressure due to carbon dioxide gas in the coffee ground emulsifying with oils when hot water is injected. In the case of nitro cold brew, nitrogen gas is injected into cold brew coffee under pressure. The effect is a frothy layer on top of the coffee that gives the coffee a creamy texture.
The strong bitterness of nitro cold brew black coffee is liken to drinking bitter Guinness Stout beer. For sweeter version, try Starbucks' nitro cold brew with vanilla sweet cream — available over-the-counter in their cafes and also in cans / bottles.