Affogato: Espresso poured over
Shot of espresso. (30ml).
(With thanks to E.
machine boilers can range in size from 120ml in domestic machines to 12
litres and over in commercial machines. Lower end domestic espresso
machines and domestic superautomatic machines often don't have boilers
at all, instead using thermoblocks.
|Burrs: Burrs used in espresso
grinders can be flat, as in the picture, or conical. They MUST be sharp
in order to provide the precision necessary for correct espresso
brewing. Cheap burr grinders sold at appliance stores are unable to
cope with quality espresso machines.
|Cafe Crema: A long espresso drink
(150 - 180ml) produced using at least 14g of coarser ground coffee
in the double filter basket for a total shot time of 20 - 25 seconds.
|Cafe Latte: An espresso based
drink consisting of a single espresso shot topped up with hot
microfoamed textured milk and finished with no more than 1cm of foam on
|Cappuccino: An espresso based
drink consisting of one-third espresso, one-third hot milk and
one-third milk foam, sometimes topped with chocolate powder. Normally
made with a double espresso, a weak cappuccino can be made with a
single espresso and the volume topped up with milk.
|Descalers: Espresso machine
descalers are organic acids (such as citric, tartaric and sulfonic
acids) which dissolve calcium and magnesium carbonates and sulfates
deposited inside espresso machine boilers and the brew water
path. They are normally "food safe" and are added to the incoming water
supply. The machine is then flushed to remove both the acids and the
scale. Descalers are not suitable for backflushing or cleaning.
|Detergents: Espresso machine
detergents are generally based on tri-sodium phosphate, and are used
for backflushing (with the blind filter) and cleaning exterior machine
parts like drip trays and portafilters. They must NEVER be added to the
tank or boiler, as they will cause serious contamination and may damage
sensors and valves.
|E-61 Group. Originally patented
by Faema, this group is a massive (4kg) chunk of chromed brass,
designed to act as a heat radiating temperature stabilizer as part
of a heat exchanger water circulation system. It brought unprecedented
temperature control (and style) to the commercial espresso machine.
Currently starting to appear on "semi-commercial" domestic machines as
|Espresso: 28 ± 2.5ml of coffee
produced from 7 ± 0.5g of finely ground coffee extracted at a pressure
of 9 ± 1bar at a temperature of 90° ± 3°C for a time of 25 ± 2.5
seconds. Should be rich, unctuous, bittersweet in flavour.
|Grinder: Commercial espresso
grinders are "Burr Grinders" and almost always come with a doser
attached to them, see grinder at left. Domestic grinders can also have
dosers, or be doserless, as with the grinder at right. All espresso
grinders come with rests ("doser forks") for the portafilter.
Filter baskets: Stainless steel
baskets of various size, shape and depth (depending on machine) with
holes in the base. Ground coffee is dosed into the basket,
which is held in the portafilter, and the assembly is then
locked into the group before brewing commences. A basket with no holes
(left) is called a blind filter, and is used for backflushing
machines with 3 - way valves.
(Gruppo in Italian.) Sometimes called the brew-head. The business end
of the machine; the bit the portafilter locks into, and from which the
pressurized hot water is forced through the coffee in the filter
basket. Consists of a metal cylinder with passages in it for water,
sometimes also has various valves built in. Surrounded by the group
gasket and the locking collar which hold the portafilter in
place, and topped with the shower screen which distributes the water.
Gasket: The rubber ring inserted in the group to ensure that the
portafilter and filter basket combination seal tightly, stopping leaks.
Group gaskets harden with age and should be replaced when they no
longer seal properly.
An espresso based drink consisting of a single espresso shot in a small
glass, with a dash of cold milk and a dot of hot foam added to the top.
Also called (incorrectly) "Group Handle". The carrier which holds the
filter basket, and which locks into the group to provide a watertight
seal for the pressurized water to infuse the coffee. The espresso then
exits the portafilter via the spout(s). Portafilters normally have
single or double spouts, but triple spout versions do exist. Domestic
machine portafilters always have 2 spouts.
The puck is the disc shaped cake of coffee left behind after brewing.
It should be firm, cohesive and dry when knocked out of the
Pump: Most commercial espresso machines use rotary pumps connected to
an electric motor. The most common brand is Procon. The pumps
themselves are fairly small, but the electric motors are quite big.
In most domestic machines the showerscreen is a simple perforated
stainless steel disk which distributes the water from the group onto
the coffee in the filter basket. In high end and
commercial machines the disk is 2 - part; a solid stainless steel
disc back with relatively large holes and a fine stainless steel mesh
front, which provides a more even water distribution.
3 - way Valves: These valves serve to relieve the built up pressure in
the group and portafilter assembly immediately after brewing. They are
normally actuated electronically via a solenoid, but mechanical
versions of this valve (as on the original Faema E-61 group) also
exist. They are present in high end domestic machines and all
commercial machines. ONLY machines with these valves can be backflushed.
The Tamper is a device for pressing the coffee into the filter basket,
so that there are no voids in the coffee and the pressurized water
cannot find the path of least resistance (channelling) at the edges of
the coffee. There is some debate over how critical tamper size, shape
and pressure is, but in my experience correctly ground coffee requires
only a light tamp.
A metal block with a large number of narrow channels inside, heated by
an external element. Used in low end domestic espresso machines.
Picture shows an opened thermoblock.
Pump: Pump domestic espresso machines and some of the lower end small
commercial machines use vibration pumps, most of them produced by ULKA