Long black coffee took off in Australia and New Zealand during the second half of the 20th century, and now it's finally more common in U.S. coffeehouses. Surprising it's taken so long given how straightforward it is to make one: Pull two shots of espresso over hot water. And yet, as Good Food magazine's Matt Holden writes, "It's possible that no brew is so misunderstood as the long black." The misunderstanding, it seems, comes down to brew time, when you pour and what temperature the water is. Getting those right will turn a drab espresso into a boldly flavored brew with a thin layer of thick crema balancing on top.
Whether you use the hot water from the espresso machine to pour the double shot over or you boil it with a kettle, start with fresh, clean, cold water, and if you have filtered water, use it. The purer the water, the purer the flavor of the long black. And when you're boiling the water, heat it to between 190 and 200 degrees Fahrenheit before adding the double shot. Most espresso machines will boil water within this range, but if you're not sure, use a kettle and a thermometer instead.
The Coffee Blend
The second key to the perfect long black coffee is the espresso coffee blend you use. Avoid dark-roasted blends, which tend to result in a bitter-tasting brew, and go for lighter blends that achieve a sweeter, smoother flavor. Coffeeresearch.org recommends using espresso within four days of roasting for the freshest taste. And when you're ready to make that double shot for your long black, use between 14 and 17 grams of coffee.
The Brewing Method
The third key to the perfect long black is the order of events when brewing. Begin by brewing the double shot of espresso as you normally would, following the directions that come with your espresso machine. Brew time should be no longer than 30 seconds; any longer, and the long black will taste burned. While you're waiting, pour the hot water into a cup and have it ready. When the espresso is ready, place the cup under the espresso spout and pull the double shot over top.