It would be a real treat to be able to create your own espresso drinks at home, wouldn’t it? But before you go out and buy an espresso machine you have to learn about the various types of machines on the market.
Let’s look first at the electrical steam driven espresso machine. These are the least expensive espresso machines obtainable. Steam pressure is what makes these machines function. Water heats up in an airtight chamber until it becomes steam and is then rapidly forced through ground espresso and right into a carafe or cup. Electric steam machines are only able to get the water pressure up to about 1 bar which is really not enough pressure to extract and brew actual espresso (the preferred pressure at which espresso is brewed is about 8 bar). And this lack of pressure doesn’t produce a very good crema. These machines will typically include a steam wand for steaming and frothing milk. In my opinion these types of machines should really not be considered as espresso machines because the best they can do is create a strong cup of coffee.
Next we’ll talk about a manual machine that utilizes a lever and piston. Instead of utilizing pressure generated by steam, the pressure utilized in a manual lever machine to brew espresso is created by a piston that is attached to the lever, which, when pulled, forces the heated water through the ground coffee. This type of espresso machine gives you total control over the entire brewing process such as dosing, tamping, pulling the manual lever to pressure the water through the espresso grounds, and timing each of these operations. Pre-heated water is drawn to the brew group when the lever is moved up which moves the piston upwards. When the lever is subsequently pulled down it forces the hot water, under pressure, through the ground coffee. This is where the phrase “pulling a shot” comes from. These lever and piston devices are capable of producing a pressure of 8-9 bar, the benchmark pressure of a genuine espresso drink.