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15. Coffee Education
What is Espresso?
Espresso is “Pressure brewed coffee”, which means that the coffee is brewed under
pressure. The pressure can be created by either a pump, piston or through steam pressure.
Your Expobar is a Pump style of espresso machine, which is the best type available. The
pressure is necessary to create the crema, which is the golden-colored creamy foam on
top of the espresso.
What is Crema?
Crema is the golden layer of foam that you will find on top of your espresso. The crema
is what holds many of the unique flavor characteristics of you espresso.
SCAA’s (Specialty Coffee Association of America) definition of Espresso
Single shot: 7 Grams of ground coffee and 1 to 1.5 ounces of liquid espresso
Double shot: 14 grams of ground coffee and 2 to 2.5 ounces of liquid espresso.
Basic Bean info
There is no such thing as an espresso roast. There is no such thing as an espresso bean.
The beans used for brewing espresso will be either a blend of certain varieties of beans
that will produce the flavor characteristics that the roaster is looking for, or a single origin
bean that has good flavor characteristics for Espresso.
Some people like a dark roast and some people like a light or medium roast. The color of
the roasted beans has nothing to do with the brewing equipment used. A dark roast coffee
can be used for drip or espresso. What will make it taste good is the blend of beans used.
The blend used for espresso will be different than the blend used for drip coffee makers.
Arabica and Robusta Beans
Arabica
Arabica is grown at higher elevations and is more expensive because it is harder to farm.
It is generally agreed that the Arabica is the higher quality bean.
Robusta
Robusta is grown at the lower elevations and is a bean with a higher acidity. Some
roasters may add some robusta beans to give the espresso an edge, and also because
robusta beans work well for milk based drinks. The robusta may also be used to help give
the coffee a thicker crema.
Steaming and Frothing
There is a difference between steamed and frothed milk. Steamed milk is milk heated
with steam from a steam wand. Frothed milk is also heated, but air is injected into the
milk to create froth. Different techniques can be used to create either creamy or foamy
froth. Low fat milk froths easier and creates a more airy froth. Milk with a higher fat
content requires more technique to create froth and will create a creamier and sweeter
froth.
