English
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La Marzocco, S.r.l. Firenze, Italia
V1.3
8. History and Use of the “La Marzocco” Coffee Machines
you have established the amount of ground coffee required for
each cup, the grinder must guarantee a constant amount from
dose to dose. It is best to grind coffee from time to time, trying
not to leave any ground coffee in the grinder overnight and during
days off.
4)
Espresso Machine
Among other things, the espresso machine must guarantee
the following qualities:
a)
the most appropriate water temperature for the type of coffee
mix used, constant in time so as to ensure that a good cup of
coffee may be prepared any time, whether you have to make
several, one after the other, or one from time to time.
b)
a constant water pressure through the brewing group and
the coffee mix.
As far as the quality b) is concerned, it is usually obtained by
means of the same system in all the “continuous brewing” type
machines, that is by using a positive-displacement motor pump,
while quality a) can be obtained with various systems.
The great majority of manufacturers uses systems which are
very similar to one another. The underlying principle is to heat
up the water used for brewing coffee, which comes directly
from the pipes and is pushed by the motor pump, by running it
through coils or cartridges (small containers) which are located
in the boiler. It follows that the latter must be quite large, which
entails a noticeable power consumption, and the temperature
may be controlled exclusively through a pressure switch, a
device which is specifically designed for controlling pressure
and not temperature; indeed, the temperature changes every
time the water/steam ratio in the boiler changes, and even more
so when the latter is replenished with cold water.
It is quite obvious that the coils or cartridges which supply water
to the brewing groups are very sensible to the above changes.
Furthermore, the heat exchange between the main boiler and
the coil varies greatly when, as time goes on, conduction of
heat is reduced due to calcium deposits forming on the inside
and outside of coils or cartridges. In light of the above, and to
avoid wastage of electric energy required to keep large
quantities of water at operating temperature/pressure, when
only a small part is utilized, our machines have been designed
with 2 small boilers, of the size which is most suited to the kind
of services they have to offer.
One of them, a “STEAM GENERATOR”, is used to deliver steam
and hot water for various drinks while the other, a “HOT WATER
GENERATOR”, is used for the coffee. The latter, therefore,
produces hot water used exclusively for brewing coffee, which
will flow out, every time the specific group is activated, thanks to
the force of the cold water (actually produced by the positive-
displacement pump). The temperature of such water is
controlled by an electronic temperature controller and a
temperature probe. This system is extremely sensitive and
has an accuracy of 0.2 C, electronically adjustable to 1/10 of a
degree in order to adapt it to the optimal temperature, depending
on the type of coffee mix being used.
The brewing groups, work like thermal “flywheels”. They are
welded directly to the coffee boiler and are thus an integral part
of the boiler itself. The boiler assembly is shaped in such a way
that each group is located at a greater height than the boiler, so
that, just like in the elements of a thermosiphon, a natural
circulation of hot water takes place within each group, at the
same temperature of the boiler and kept constant by the
electronic temperature control system described previously. The
use of these small boilers, completely independent from one
La Marzocco has been producing espresso coffee machines
for use in cafés since 1927.
In February of 1939, when machines being manufactured were
exclusively of the vertical boiler type, “La Marzocco” designed
and built the first horizontal boiler machines, for which it obtained
a “patent”.
The Second World War brought an end to production of coffee
machines, and the fact that La Marzocco was a company of just
the right size (small-medium) allowed it to keep in touch directly
with its clients and specialty “cafés”, which meant being able to
get more accurate feedback information, concerning the needs
of the final consumer and market trends, which could then be
put into practice.
Throughout time, various machines have been designed and
built: of the type operating on “Water/Steam” and on the principle
of “Hydrocompression”, and of the lever operated, air and steam
type; semi-automatic and automatic, with mechanical and
electrical actuators, up until current production which consists
of machines allowing continuous “brewing” operation.
PECULIAR CHARACTERISTICS OF LA MARZOCCO COFFEE
MACHINES
The great majority of the espresso coffee machines being built
today, of almost any brand, are of the “continuous brewing”
type, whose basic concept is to use the same water in the
tubing, directly to brew coffee by increasing its pressure
mechanically and heating it in advance. This has eliminated a
particular problem encountered with older machines, which
made use of water from the boiler, consisting of the “overheating”
of the brewing groups which, at times of heavy workload, would
give coffee a particularly unpleasant burned taste.
In any case, a good cup of coffee is the result of 4 highly
interdependent components, to such extent that if only one of
them is not quite in perfect harmony with the others, the resulting
cup of coffee will turn out not quite as pleasant in taste.
The 4 basic components are:
1.
coffee bean mix;
2.
water;
3.
coffee grinder;
4.
espresso machine.
1)
Coffee Mix
Independent of the various qualities of coffee that make it up,
the type of toasting, etc., the freshness of the coffee beans and
the way they are preserved is very important.
For coffee beans to be used on espresso machines, it’s a
good rule of thumb to wait at least 8-10 days after toasting, so
that the beans may re-absorb part of the humidity they lost
during the toasting process itself, and to use coffee beans
within 3-4 days of opening their container.
2)
Water
Within the limits imposed by the type supplied locally, water
should be free of bad savours and “softened” using a suitable
water softener in order to avoid calcium build-up; in any case,
hardness should not exceed 3-5 grains. If water tastes like
chlorine it is recommended that you use an actived carbon
filter.
3)
Coffee Grinder
It must allow you to grind coffee beans in a wide variety of
granule sizes, in the most uniform manner possible and once
Operators Manual - ENG - V 1.3.pmd
30/10/2006, 14.34
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