A long espresso, also known as a lungo, is an espresso made with more water than usual, resulting in a larger, milder shot thats similar to a regular coffee. A typical recipe for an espresso is about 1:2, or 18 grams of ground coffee to 36 grams of coffee, while a lungo usually has a ratio of 1:3 to 1:4 coffee to water. This means that a serving of lungo coffee is usually twice the size of a typical espresso. While the amount of caffeine will stay relatively the same, the drink becomes more diluted and weaker by volume than a regular espresso. Lungo coffee is made using an espresso machine but with two times the amount of water to the same weight of coffee to make a much longer drink. The extraction time of the dose is determined by the variety of coffee beans, their grind, and the pressure of the machine. While some purists may argue that long shot espresso is not "true" espresso, it has gained popularity in recent years as a way to explore different flavor profiles and brewing techniques.