Espresso
The best espresso should be extraordinarily
sweet, have a potent aroma, and flavor similar to freshly
ground coffee. The crema should be dark reddish-brown and smooth, yet thick. A perfect espresso
should be enjoyable straight with no additives, yet bold
enough to not disappear in milk. A pleasant and aromatic
aftertaste should linger on the palate for several minutes
after consumption.
The following steps describe in detail how to make espresso. You will also learn about the various factors and problems with espresso that
limit its perfection. If any of these factors are off, you will not achieve a high quality espresso.
Making Perfect Espresso
Blending Espresso
Without
a good espresso coffee blend you cannot have a good espresso.
The best espresso coffee beans are blended to achieve the sweetness, aromatics,
and smoothness desired in espresso. The espresso blend must
also be fresh. We recommend using espresso within
four days of roasting. Please see the
espresso blending section for help on creating your
own blends or order some excellent espresso blends from roasted coffee suppliers, such as Caffe
D'arte or Espresso
Vivace.
Roasting Espresso
Too often
you will find espresso roasted very dark. This
results in a bitter, charcoal tasting
brew. People that know how to make an espresso will
roast light to preserve the aroma and sugars. For more information, read the section about espresso roasting.
Grinding Espresso
The grind
must be continuously monitored throughout the day to achieve
an extraction time of 25-30 seconds. Do not change
the pressure you tamp with to compensate for a grind that
has become too large or small. For more information, read the section about espresso grinding.
Espresso Grinder
A high
quality burr grinder is essential for espresso.
A conical burr grinder is preferred to flat burrs since
the particle size is more even, they last longer, and
the coffee is not heated during the grinding process.
If the burrs become hot the coffee aroma will be diminished. A conical/parallel
hybrid blade is considered the best design by many coffee
professionals.
Dosing Espresso
Coffee
must be freshly ground to achieve peak flavors.
Grind and dose on demand. When someone orders an
espresso grind only what is necessary for one shot, dose
properly, tamp, and brew. Discard any espresso grounds
that are not used within 30 seconds. For more information, read the section about espresso grinding and dosing.
Distribution in Portafilter
Distribute the coffee evenly after dosing in the porta-filter
before tamping.
Tamping Espresso
Tamp
the coffee once very evenly with 5 lbs of pressure, then
once with 30 lbs of pressure, and polish 720° with 20
lbs of pressure. For more information, read the section about espresso tamping.
Water mineral content
The water used for espresso must be filtered.
Some cities must even compensate for the mineral content
of their water. Over time oxygen will be forced
out of the water in the espresso machine leading to off
tasting water. Try filling a small glass with water,
letting it cool, and tasting it for off flavors.
If the water tastes strange you may want to dump the tanks
daily and begin with fresh water.
Water temperature
The water temperature should be stable and somewhere
between 92-96°C. Choosing the best espresso machine
is very important to both water temperature and temperature
stability.
Temperature stabilizing
A stable temperature helps ensure that you prepare excellent espresso. For more information about
stabilizing the temperature of your espresso machine, read about espresso temperature stabilizing.
Water pressure for Espresso
The pressure of the water forced through the espresso
should be between 9 and 10 atm. This pressure is
responsible for the development of the crema.
Boiler pressure
The boiler pressure determines the amount of water to
be incorporated in the steam. If your milk is not
foaming correctly as described in the section on latte art, you may want to experiment with different
boiler pressures. Boiler pressure, however, should only be altered by
professionals. You can check your boiler pressure
by looking at the boiler
pressure gauge on the front of most espresso machines.
Extraction time
Extraction time to fill two 1-oz cups should be between
25-30 seconds. Despite the time the pump should
be turned off if the espresso becomes slightly lighter
in color. The goal is to have a dark red espresso
take approximately 25-30 seconds to brew with no change
in color. Fore more information, read the section on extracting espresso.
Porta-filter and basket
The porta-filter should always remain the same temperature
as the water used to brew the espresso. Therefore
it should always remain in the group head. The basket
should hold 16-18 grams of coffee and must be straight
walled. Curvatures in the basket will lead to uneven
extraction.
Timeliness
Act
quickly, but carefully. You should spend no longer
than 30 seconds for the time it takes to dose, distribute,
tamp, pre-heat, and brew the espresso.
Espresso machine cleanliness
Coffee machine cleaning is probably the biggest problem with espresso today.
If the machine, basket, and porta-filter are not cleaned regularly, the espresso will always taste rancid.
Espresso grinder maintenance
Everyday the burr blades should be swept clean.
Between shots you may want to brush out the excess espresso
that gets stuck between the burrs and the dosing chamber.
The burrs must be replaced at least yearly so that they
continue to produce coffee granules with a maximal surface area.
Environmental Factors
The humidity and temperature will change throughout
the day. Since coffee is hydroscopic (absorbs moisture),
the grind size must be changed throughout the day to achieve
a brew time of 25-30 seconds. The temperature will
not affect the espresso like the humidity, but it is important
to avoid exposing the coffee to any high temperatures
until brewing.
Espresso cup
The espresso cup should be pre-heated from a source other
than the espresso machine. Filling a cup with water
from the espresso machine prior to brewing the espresso
will lower the temperature of the water in the boiler
and the espresso extraction will be uneven. The
espresso cup should have thick walls and a narrow mouth
to retain heat and aroma, respectively.
Practice makes perfect
If you want to learn to make espresso, it is essential to practice and experiment.
The key to making espresso is to realize that it always has further
potential. By changing any one of these factors
you can improve or diminish its potential. Espresso
preparation is an art that demands the precision and dedication
of science. I have never achieved, nor have ever seen anyone make
a perfect espresso. A perfect espresso is more of a
concept than an actuality. The beauty is that espresso
is volatile and difficult. If it were easy, we would
develop a machine that knows how to make a perfect espresso every
time. There are so many factors involved in espresso
preparation that only a human mind and a passionate heart
can begin to understand and control its complexity.