The Speedster is available in the UK
exclusively from ESPRESSO WORKS, for
5800 EUROS, subject to availability and
lead times. Price is subject to
fluctuation - please enquire.
Overview
From 1995 till 2004 Kees built the Mistral series of espresso machines using
boilers and groups from La Marzocco.
During those days kees also were the official importer of La Marzocco machines
for the Netherlands.
Through the years they acquired some of the old type paddle-groups from the GS
machines. As they could not bring themselves to dump these they eventually decided to
use these in a fun-project: building a small series of one-group machines,
especially designed to use these groups for their proper purpose. This machine
was called Speedster.
A total of six were built in 2001 and sold remarkably quick to friends and
relatives.
These first Speedsters were technically rather simple. The rear steamboiler
was small, with the same diameter as the coffee boiler, as Marzocco used to do
when they started using their double boiler system. Temperature of the steam
boiler was controlled by a pressostat. The coffeeboiler temperature was
monitored by the standard Marzocco mechanical Fenwall temperature switch.
Soon after Kees showed this machine, mails and
telephone calls started to come in and they soon realized it might be worth
their while
to develop it into a true production machine.
As the Mistral was coming of age Kees decided to design a completely new,
second series - Mistral. La Marzocco expressed the wish to buy this design and
to build the new Mistral themselves. This ended Kees' reason to be LM
distributor for the Netherlands. Re-designing the Speedster thus became the
perfect opportunity to finally coming to grabs with the long existing wish to
develop our very own multiple boiler system with matching group.
Creating a new machine (only the general look of the initial Speedster was
kept) complete with a totally new technical set-up proved to be time consuming.
The new Speedster was introduced at the 2008 Copenhagen W.B.C. fair.
All information is provided as-is for guidance only, without warranty or
guarantee of accuracy. E&OE.
Features
• Construction in stainless steel only, including frame, also the black
powder coated parts
• Fully new developed double boiler system in stainless steel
• Completely new designed group in stainless with high neck
• Electronic temperature controllers driving solid state relays on both
boilers, PID on coffee boiler, no moving parts
• Steam boiler equipped with a heat-exchanger to pre-heat the water going
into the coffee boiler.
• Diffuser in POM plastic, doesn`t get dirty as soon, easy to clean and
doesn`t affect the water temperature on its last path towards the coffee.
Diffuser is easily removable.
• No screw to hold group screen, yet screen and rubber gasket are easily
removable through openings in the bottom plate of the group to reach the sides
of the rubber gasket ring
• Self bleeding group
• Group solenoid valve in stainless only
• 0.6mm jet
• Progressive pre infusion cylinder, spring loaded chromed piston shaft
actually moves up through body panel during extraction
• External commercial grade rotation pump with motor
• Two different temperatures of hot water available through one switch
• Activation of group by small lever with shift gate: off-infuse-brew
• Strong and long lasting steam power, steam tip with 4 holes
• Filter holders with teflon coating on inside
• Drain tray adjustable in height
All information is provided as-is for guidance only, without warranty or
guarantee of accuracy. E&OE.
Technical
The Speedster has 2 boilers.
The coffee water boiler is made from 3mm stainless steel tube and 6mm thick
flanges. The steam-hot water boiler is done in 2mm stainless tube with 6mm
flanges.
There is a large hole on top of the coffee water boiler on which the group is
installed. The group is made in 4 and 5mm stainless. The group is welded, also
onto the boiler. The welding is done both on the outside as well as the inside
to prevent crevices which may cause corrosion. The neck of the boiler is
situated vertically to allow for a proper constant thermo-siphon heat flow
inside, reaching the full length and height of the group. Both the cover as the
bottom of the group are removable, sealed by o-rings.
The entire frame is made from 3mm stainless steel, including the black powder
coated parts. Body work is in 1mm stainless, drain tray in 2mm.
Steam Boiler
The rear steam boiler has a total capacity of 3.5 litre. An electronic
temperature controller gets it information through a very precise and fast
reacting probe, located in the steam, and activates the heating element via a
solid state relay. The heating element provides a powerful 1.800Watt. This is
divided over two elements of 900Watt each, mounted on one flange. There are no
moving parts in the heating system.
The steam valve has a large knob, stainless steel wand and a steam tip with 4
holes in fan-shape, each with a diameter of 1.2mm.
Activation of the hot water is done by a switch. The large manual valve on
the machine is empty inside, only providing a connection between inner tube and
outside wand, visually symmetric to the steam valve.
Two different hot water temperatures can be supplied by one toggle switch.
Inside the machine hot water running from the steam/hot water boiler towards
the hot water valve is directed first through a mix manifold. On this manifold 2
solenoid valves are installed, one for hot, one for cold water. The cold water
flow is restricted by a 0,6mm jet. Pushing downwards the long lever toggle
switch activates both solenoid valves and the pump, resulting in a quiet flow of
hot water with a temperature of just below boiling point. When the lever of the
toggle switch is pulled upwards, only the hot water solenoid is activated. This
results in hot boiling water flowing directly from the boiler to the wand.
Coffee Boiler
The cold water entering the machine is first directed through a
heat-exchanger located inside the steam boiler. Exiting the heat-exchanger its
temperature is higher than needed. It is cooled down by flow-crossing the
outgoing hot water with the incoming cold water and running through an extra
long tube outside the boiler before entering the coffee water boiler.
At entering the coffee boiler it first travels through an internal tube over
the entire length of the boiler.
The temperature of the coffee water is measured and controlled by a highly
sensitive probe connected to a PID (Proportional, Integral, Derative)
controller. This controller activates the 900Watt heating element via a solid
state relay. There is no moving part in the entire heating and controlling
system. This ensures an extremely fast reacting system as well as a very
reliable one. The PID functions almost make this controller intelligent. It
learns from past behavior and actually responds ahead. This results in an very
precise temperature management by short pulse activation of the heating element.
The brew water temperature can easily be adapted by just pushing a button at the
front of the machine. It is adjustable to 0.1 degrees Celsius.
The Group
The group is self-bleeding.
Air can be compressed, water cannot. It is important all air is driven out
from the coffee boiler. This is done automatically when the brewing lever is
used for the first time after installation.
After going to great length to achieve a perfectly exact stable temperature
it is important the water does not lose any of its heat, until it reaches the
coffee grounds. When brewing, water never leaves the coffee water boiler/group
on its path towards the coffee.
It runs via a tube, starting from directly under the group cover, to the
three-way solenoid valve. A 0,6mm jet is installed at the entrance of this tube.
We designed and made the base of our solenoid valve especially in stainless
steel. Brass would absorb too much heat, stainless steel has a heat transfer
capability of approx. ten times less than brass. This base forms one end of the
group neck and is in direct contact with the water. From the solenoid valve it
is routed through another tube towards the bottom of the group. Both these tubes
run virtually horizontal inside the group neck. This path makes for an extra
temperature stabilizing effect.
Water running from solenoid to the coffee, will not hit the stainless steel
bottom plate. The dispersion plate reaches up through the bottom plate, so the
water directly enters the dispersion plate. This plate is made in POM plastic, a
fully neutral material regarding transferring heat. Also, fats and oils do not
adhere easily to this material, effectively keeping it clean. This plate
consists of two pieces offering a nicely divided dispersion, held in place by
two screws.
The group screen is hold in place by the surrounding rubber group gasket. To
pull out the gasket with screen for controlling, cleaning and replacing, a space
is provided right above each bayonet cut out in the filter holder locking ring.
In this way you can reach to the top of the group gasket at two opposite sides
and pull out the rubber gasket ring together with screen.
The rubber gasket ring sits against the bottom of the group. At the bottom of
the group a small outward ridge is machined. This ridge is pushed into the
rubber gasket each time the filter holder is locked into the group, as an extra
sealing surface. The slight moving up of the gasket ring, because of the
flexibility of the rubber, provides a soft comfortable feel for the barista.
Full sealing is achieved without having to pull the filter holder firmly.
Both filter holders are coated in Teflon on the inside. This ensures no build
up of baked-on oils and fats. No scrubbing is needed, just a quick wipe with a
paper or towel. It also helps a bit against the loss of temperature when the
coffee runs to the cup.
Infusion
The importance of pre-infusion is generally vastly under-estimated. Properly
infusing the grounds makes for and even wetting and swelling of the grounds,
preventing channeling. More importantly however, pre-infusion allows a slow
warming and softening of the fats and oils in the coffee grounds, before
extracting these with high pressure, resulting in a higher yield of solids in
the cup. These fats and oils are in fact the actual carriers of the delicate
aromas and flavors. Machines with a slight variation in brewing temperature tend
to offer a larger spectrum of different flavors from the coffee grounds. On
machines offering a very strict temperature a well-executed pre-infusion becomes
imperative, otherwise they might not be able to extract the full area of
complexities hidden in the coffee.
The Speedster is standard equipped with a threefold infusion system.
A 0.6mm jet is positioned ahead of the solenoid. As soon as the solenoid is
activated the water runs through the empty tube from solenoid to coffee. This
allows for a soft start of the extraction process as any pressure will first be
lost because all empty spaces (tube, dispersion plate, space between dispersion
plate screen) need to be filled. Pressure will only raise after the coffee bed
has been fully saturated.
- The brew activating shift-gate lever has three positions: stop-infuse-brew.
-
The center infuse position opens the solenoid but does not activate the pump.
-
Water now enters with line pressure only.
-
The lower position also activates the pump.
-
These possibilities allow the barista to give the above process the time he/she
thinks necessary to fully develop.
-
Note: as soon as the group solenoid is activated, the filling up system of the
steam boiler is automatically disconnected. This prevents any unexpected
interruption or sudden loss of pressure during the infusion process.
The base of the group solenoid has a third tube incorporated. This 4mm tube
runs to the progressive pre-infusion cylinder. A piston with spring sit inside
this cylinder. As soon as the coffee grounds are fully saturated, the pressure
will start to raise.
This first raise in pressure is absorbed by the spring. Because this is a
spiral spring its tension will raise as it gets compressed. The more the piston
is pushed in, the more difficult it becomes to push it further. This results in
a pressure onto the coffee grounds that is at first fully absorbed, then slowly
and progressively raised.
The effect is a long, slow and soft infusion. This effect even occurs when
the brewing lever is jammed to its lower position right away, solenoid and pump
activated at once.
The travel of the piston, and thus the developing infusion, can be checked by
the barista, as the rear shaft of the piston moves up through the front body
panel.
An additional aspect of the progressive pre-infusion cylinder is some
cleaning. After the extraction process is ended, the remaining pressure inside
the basket is purged through the internal tube and solenoid, then to the drain.
When this pressure has vanished the spring pushes back the piston. All clean
water inside the cylinder is forced through the solenoid towards the drain. This
flushes the internals of the solenoids. Of course the tube between solenoid and
coffee is not flushed, so back-flushing is still needed once in a while.
Safety
The steam boiler has two probes to monitor the level of the water inside.
The lower probe is located just above the heating element. When the machine
is fired and filled for the first time, the brain only switches on both
temperature controllers, and thus the heating elements, when the lower probe
detects water. During filling up, the coffee boiler is filled much quicker than
the steam boiler because the steam boiler fill valve has a restrictive 0.6mm jet
installed. This to have cold water enter gently, allowing the heating element
more time to keep up the pressure. So when the lower probe in the steam boiler
detects water the element inside the coffee boiler is already submerged. This
system ensures the elements cannot be turned on while not being cooled by
surrounding water. When the higher probe contacts water the brain de-activates
the fill solenoid and pump. These are activated as soon as the higher probe does
not detect water. This probe has a bent hook. The other end of the probe, inside
the boiler, is bent identically. This offers the barista some way to adjust the
level by simply turning the probe.
Both electronic temperature controllers have a restricted upper temperature
programmed. When this temperature is reached no more signal to the solid state
relay is sent.
Each boiler is equipped with an overheating cut-out switch. This switch is
screwed into the boiler flange. When it detects too high a temperature, it will
disconnect power to the element.
The steam boiler is equipped with a safety valve.
The coffee boiler system, including the heat-exchanger, is equipped with a
expansion valve, factory adjusted at 11-12 bar.
All information is provided as-is for guidance only, without warranty or
guarantee of accuracy. E&OE.
