Espresso Coffee Making
What is Espresso?
It is the best way to obtain from knowledgeably roasted coffee beans all the
pleasure that they are able to give. More practically, espresso is the
drink-in-a-cup obtained by forcing adequately pressurised hot water through a
packed layer of precisely ground coffee to extract a thick, flavorful essence in
a concentrated form.
espresso extraction video #1
What characteristics in technical detail are required to obtain
Espresso (according to the Italian Espresso National Institute)?
The following are some important conditions to obtain Espresso though
these alone would not be adequate to fulfil the quality requirements:
Necessary portion of ground coffee = 7 g 0,5
Exit temperature of water from the unit = 88C 2C
Temperature of the drink in the cup = 67C 3C
Entry water pressure = 9 bar 1
Percolation time = 25 seconds 2.5 seconds
Viscosity at = 45C > 1.5 mPa s
Total fat = > 2 mg/ml
Caffeine = 100 mg/cup
Millilitres in the cup (including foam) = 25 ml
2.5
From a descriptive profile standpoint, what are the
sensory characteristics of an Espresso?
On sight, Espresso has a hazel-brown to
dark-brown foam - characterised by tawny reflexes with a very fine texture
(absence of large mesh and larger or smaller bubbles). The nose reveals an
intense scent with notes of flowers, fruits, toasted bread and chocolate. All of
these sensations are felt also after swallowing the coffee in the long lasting
aroma that remains for several seconds, sometimes even for minutes. Its taste is
round, substantial and velvet-like. Sour and bitter tastes are well balanced and
neither one prevails over the other. There is no, or a barely perceptible,
astringent taste.
espresso extraction video #2
Should the type of coffee used in the preparation of
espresso be better in quality than the types used for other preparations?
Coffee is a fine pleasure and as such it should always be prepared from good
raw materials, but if espresso is prepared according to the guidelines, it
produces a remarkably higher extraction of both good and bad coffee components.
This is why the quality of the coffee used for espresso should be totally
faultless.
What is the milestone for the quality of espresso?
A person, with his/her knowledge, capabilities and motivation. It is indeed
the operator who selects and manages the equipment and the blend, adjusts the
equipment to the properties of the blend, and controls every step of the
preparation process to make excellent espresso. This is why the
barista is so important.
What happens if an espresso is obtained in 15 or in
35 seconds?
The blend design generally ensures that, after duly grinding the blend, it
yields 25 millilitres of coffee, by taking the best part of the substances
present in a coffee bean (glucides, proteins, fat and aromatic components) and
by leaving the less noble substances in the exhaust cake. If the extraction time
lasts no longer than 15 seconds, it means that the hot water has not taken the
right treasure with it and a part of precious substances has remained in the
powder. In addition, the beverage is going to be unbalanced from a sensory
standpoint. The espresso will be under-extracted, poor in body, more sour than expected with a
faint aroma. If it lasts 35 seconds the opposite is going to occur: the woody,
unpleasant and pungent components will be extracted from the coffee powder, and
it will be bitter.
What is the ideal cup for Espresso?
The ideal container is a white china cup, free of any inside decoration,
elliptical in shape, truncated inside while it may or may not be bell-shaped
outside, with 50-60 millilitre approximate capacity. This is the only cup
whereby it is possible to fully appreciate the look of the excellent espresso
crema, the precious
smell and the warm and smooth taste of espresso. The fresher the coffee the more
the crema.
What is the Espresso Roast?
There is no such thing called
espresso roast, although some companies want you to believe it. The roast
for espresso is different from country to country and even from area to area, if
we're talking about the USA or Italy.
The lightest of the roasts used for espresso is full city roast. Full city roast
is the darkest brown that a coffee bean can be roasted without oils developing
on the surface of the bean (SCAA). By most people this is recognised as the
ideal roast, because more flavour is preserved, and it's easier to show off the
varietal characteristics of every coffee. The overall taste is better balanced
than darker roasts. The espresso crema is richer. The quality of the beans is
not covered by the roast. Use of high quality beans is imperative. In a lot of
European countries it is quite common to include 5-10% high quality robusta
beans in the espresso blends.
A darker roast than full city roast, is the so called Vienna roast or light
french. In the finished cup of espresso, the more subtle of the coffee flavours
are lost, having been replaced by the dominance of the roast, which is beginning
to take on burnt overtones. In this style the bite of the roasting flavour is
more present in the espresso. Also, a little less flavour is available because
the flavour oils, having been extruded on to the surface of the bean, are lost
more quickly from exposure to the air.
Roasting darker than this gives the French roast or Italian roast (although a
wrong term). The sugars of the coffee bean are completely caramelized, the
oils which carry the flavour get out of the bean, and create a very shiny look.
Oils exposed to air stale quickly and give a bad taste. The burned overtones are
intense. The roast taste characteristics cover the beans varietal
characteristics, and so it's easy to use lower quality beans. The espresso taste
is quite sharp and bitter.
Learn more about espresso with our advanced guide...
Source of information: ITALIAN
ESPRESSO NATIONAL INSTITUTE
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