What is an Espresso Machine Exactly

An espresso machine is an appliance which is used to produce the traditional Italian coffee drink known as an espresso.  Those who use these machines professionally such as those found in places like Starbucks are known as barista's and the knowledge that is required to make the finest espress is concerned a craft by many Italians.

The coloquial term for producing a short of espress is known as "pulling a shot" because the older style espresso machines required the use to pull a long handle in order to produce a shot.  In order for some one to produce a shot of espresso they need to fill a filter basket with either 7-10 grams of ground coffee for a single shot of 30mL and 12-18 grams for a double shot of 60mL of espresso.  This is then tamped (compressed) into a densely packed puck of espresso.  The portafilter or group handle then holds the filter basket and this is locked under the grouphead's diffusion block.  Once the process begins pressurized water is forced into the grouphead and so through the ground coffee that is held in the portafilter.  If the water is too cold the coffee will taste sour and if the water is too hot the coffee will taste bitter.  So a good quality espresso machine should control the temperature of the brewed water so that it is within a few degrees of the ideal heat to make that perfect espresso coffee.

Using an espresso machine with produce a rich almost syrupy beverage as it extracts and emulsifies the oils that are found in the ground coffee.  The ideal double shot of espress should take between 25 to 30 seconds to arrive from the time when the machine's pump is first turned on.  By varying the fineness of the coffee grinds, the amount of pressure use to tamp the ground coffee down or the pump pressure itself can be used in order to bring the extraction time to the perfect time needed to produce a good espresso.  Most people who drink espresso prefer their shots to be poured directly into a pre-heated demitasse or shot glass so that it maintains its ideal temperature.

An espresso machine also comes with a steam wand which can be used to steam and froth milk for those milk based espresso drinks such as lattes and cappuccino's.