The large display at the front of the Slim Jim. The barista can tune the machine exactly as wished. Eco mode and a host of handy features are readily accessible via the touchpad. A shot-timer automatically appears in full view on the display, whenever the group is activated.
Each group can be activated by one of our custom “Bastones”, a small lever, which offers two programmable volumetric settings and via a pushbutton a continuous flow. The lever can also be programmed for full manual control.
Double spring pre-infusion cylinder, ensuring a slow, automatic, progressive pre-infusion process. This allows a finer grind, creating more surface, so a higher yield in the cup.
The Zappo type steam wand consists of a double walled stainless tube, with a PEEK steam tip, four holes of 1.6mm each, or optionally 1.4mm. These insulated steam wands are generally appreciated for their “non-burn” qualities, but their ability to have milk hardly or not adhere is possibly an even greater benefit.
DIMENSIONS
Approximate dimensions and footprints of the Slim Jim are shown in the illustrations. Measurements for two and three group are the same and do not include overhanging component such as the portafilter.
WEIGHT
The countertop should provide a solid base to carry the full weight of the machine: roughly 100kg for both the Duette and Triplette.
NOTES
Water supply from a water treatment system should be within 1.5m (5ft) of the machine. The water supply hose that comes with the machine has a half ball at the end of the 3/8″ nut connector. Discharge should not be further away than 1.5m, have an internal diameter of at least 32mm (1″ 3/8) and should be fitted with a trap. There must be space nearby to locate the water pump with its electrical motor.
SHIPPING CRATES
Download an overview of the shipping crate dimensions and weight by clicking here.
| Slim Jim Duette | ||||
| Coffee Boiler | 0.8ltr water | 316L stainless steel | |||
| Steam Boiler | 10.5 ltr water | 316L stainless steel | insulated | |||
| Version | Normal | High Power | ||
| Tension | 220-240 Vac | |||
| Frequency | 50 or 60 Hz | |||
| # Phase | 3 | 1 | 3 | 1 |
| Heating power steam | 4800 W | 6000 W | ||
| Heating power coffee | 2x 450 W | |||
| Peak power (no pump) | 6325 W | 7525 W | ||
| Peak current phase 1 | 8.9 A | 27.5 A | 10.7 A | 32.7 A |
| Peak current phase 2 | 8.9 A | 10.7 A | ||
| Peak current phase 3 | 9.7 A | 11.4 A | ||
| Slim Jim Triplette | ||||
| Coffee Boiler | 0.8ltr water | 316L stainless steel | |||
| Steam Boiler | 10.5 ltr water | 316L stainless steel | insulated | |||
| Version | Normal | High Power | ||
| Tension | 220-240 Vac | |||
| Frequency | 50 or 60 Hz | |||
| # Phase | 3 | 1 | 3 | 1 |
| Heating power steam | 4800 W | 6000 W | ||
| Heating power coffee | 3x 450 W | |||
| Peak power (no pump) | 6775 W | 7975 W | ||
| Peak current phase 1 | 8.9 A | 29.5 A | 10.7 A | 34.7 A |
| Peak current phase 2 | 8.9 A | 10.7 A | ||
| Peak current phase 3 | 11.6 A | 13.4 A | ||
The Slim Jim is a multiple boiler espresso machine.
Cold water entering the machine is first directed through a large heat-exchanger located inside the steam boiler. This HX is part of a thermo-siphon loop. Water leaving the top end of the heat-exchanger is of higher than needed temperature because the steam boiler is set at 125 °C. A restrictor in the circuit ensures just enough heat is flowing to keep the water in the distribution block very close to the temperature of the coffee boilers. The natural thermo-siphon flow keeps the distribution block warm during idle of the machine. A hot-cold cross-flow at the feed-side of the HX conditions the temperature of the water flowing to the manifold block during brewing. Additionally, temperature inside the distribution block is monitored with a sensor. If by any chance the water in the distribution block is too hot some cold water will be added through a mixing chamber in the flow to the individual coffee boiler, when a group is activated. The water thus conditioned will have only a minor deviance from the (pre-set) temperature of the group.
The coffee boiler is completely filled with water, the temperature of the water is measured and controlled by a highly sensitive probe connected to a PID (proportional-integral-derivative) controller. This is a control loop feed-back mechanism. A nearly intelligent system, learning from the past, responding ahead, steering the 450 Watt heating element by pulses through a solid-state relay. There is no moving part in the entire heating and controlling system. This set-up ensures an extremely fast reacting system as well as a very reliable one. The water temperature can easily be changed in the Barista menu of the interface.
The heating element is connected to a control light at the bottom of machine. Combined with the machine`s display this enables for a quick visual control to check from the outside of the machine whether all parts in the heating system function as intended.
The controller offers an ECO mode which can be automatically arranged per day, lowering the temperature of an individual coffee-boiler to 50 °C during longer periods of idle.
The coffee boiler slopes slightly to allow for a proper constant thermo-siphon heat flow inside, reaching the full length and height of the boiler and group head. Both the top and the bottom of the group head are removable, sealed by O-rings.
The coffee boilers are made from a 4mm stainless steel tube and a 10mm thick flange. The group head is made in 5mm stainless steel and is welded to the boiler. All welding is done both on the outside for looks as well as on the inside to prevent possible crevices in which corrosion is known to start. All stainless is 316L. Boiler and group head together contain approximately 0.8 litre of water.
The isolated steam boiler is located at the rear of the machine and has a total capacity of 10.5 litres. (Duette and Triplette, about 75% filled with water). An electronic temperature controller gets its information through a probe located above the water level and activates the heating element via 3 solid state relays. The heating element provides a powerful total of 4.800 Watt (normal) or 6.000 Watt (high power). This is divided over 3 heating spirals mounted on one flange. There are no moving parts in the complete heating system. Each heating spiral is connected to a control light at the bottom of machine. Combined with the machine`s display this enables for a quick visual control to check from the outside of the machine whether all parts in the heating system function as intended.
The steam boiler is made in stainless steel 316L, which is more resistant against aggressive water than stainless steel 304 and has a long life expectancy in an espresso machine. The controller offers a programmable ECO mode, lowering the temperature of the steam boiler to about 70 °C during longer periods of idle or overnight.
Steaming
As standard, the steam valves have a turning knob. From closed to fully open requires less than half a turn. As an option, the mechanical steam valves at left and/or right can be activated with a toggle type lever or even by foot activation: an air bulb on the floor activates an electrical switch inside the machine which in turn activates a solenoid valve with a large passage. This solenoid valve is either fully open or fully closed. The steam flow/power can be decreased by the use of the original steam valve to match the size of the pitcher. When adjusted, the foot-activated valve opens always immediately at the preferred flow, enabling speedy steaming.
Hot water dispensing
Hot water can be dispensed in two manners:
1. Pressing the push button switch results in dispensing mixed water for an adjustable number of seconds. The switch activates two solenoid valves and the pump simultaneously: hot water from the steam boiler passes through one valve, the other valve supplies cold water at pump pressure. Cold water addition is restricted by an adjustable needle valve in the manifold such that the temperature of the water dispensed can be adjusted between approximately 60 and 100 °C. This mix of hot and a bit of cold water results in a steady, non-spattering stream from the hot water spout and can be adjusted to be excellent for making Americanos or green tea.
2. When the toggle switch is pressed downwards only the hot water valve opens which results in water flowing directly from the steam boiler to the spout. Releasing the toggle switch will stop the flow immediately. At the moment the toggle switch is pressed down the temperature of the water dispensed quickly rises to boiling point and will start to sputter. The boiling water is excellent for making black tea.
Steam boiler fill
Filling of the steam boiler is prohibited while a group is active. This setting eliminates flow-rate decrease and subsequent variations in brew-pressure during the infusion phase. The disadvantage of this setting is that the steam boiler may never start to top-up in a high-volume location where at least one of the groups is active for uninterrupted periods of time while also dispensing hot water and, with minor impact, steaming milk. For extremely high-volume locations the setting can be changed such that the steam boiler starts filling as soon as the water level drops below operational.
At first installation it is important all air is bled from the coffee boiler. Air compresses; water does not. When you first activate the group solenoid and pump, incoming water expels air because the pickup tube sits directly under the group top, the system’s highest point. Once the system reaches its target temperature, the challenge is avoiding temperature variation before water reaches the coffee.
Thermosyphon flow begins with temperature change: heated water rises, flows to the top of the group head, cools slightly, then returns to the boiler bottom. Boiler and group geometry allow warm and cool flows to pass freely. The most stable temperature, called the “sweet spot”, forms under the group top, where the pickup tube sits, feeding the stainless steel three-way solenoid valve at the boiler’s lower, hottest location.
During brewing, water never leaves the boiler/group assembly. It runs through a tube under the group top to the solenoid valve, then through another tube to the group bottom. Both tubes run parallel high in the boiler, adding thermal stability. The stainless group bottom plate sits low and remains cooler than the water; the system prevents heat loss here.
The dispersion block extends through the bottom plate so water enters it without touching the metal. Made of temperature-neutral polymer, it stays cool, preventing coffee oils from baking on and keeping it clean longer. Two block sections ensure even dispersion.
The group screen is held by the gasket. A supplied tool removes the gasket and screen for service. The gasket seals against a small ridge in the group bottom; its flexibility provides soft locking without force and resists heat-induced hardening.
The screen’s circumference seals against the group bottom, blocking grounds from entering the group. Its thick base resists deformation, is perforated, and covered by a stainless membrane for even extraction and effective filtering during pressure release, helping keep the group interior clean.
The Slim Jim is equipped with multiple boilers: one large stainless-steel steam boiler to produce hot water and steam, one stainless steel boiler per group to brew coffee. A heat-exchanger with balanced cross-flow and an electronically controlled cooling circuit ensures well-conditioned supply of pre-heated water for the coffee boilers to ensure enormous capacity in a relatively compact machine. Each boiler has its own electronic temperature control system, heating element and safety devices, offering extremely precise temperature stability at high volume.
The Slim Jim is equipped with multiple boilers: one large stainless-steel steam boiler to produce hot water and steam, one stainless steel boiler per group to brew coffee. A heat-exchanger with balanced cross-flow and an electronically controlled cooling circuit ensures well-conditioned supply of pre-heated water for the coffee boilers to ensure enormous capacity in a relatively compact machine. Each boiler has its own electronic temperature control system, heating element and safety devices, offering extremely precise temperature stability at high volume.
The steam boiler has two probes to monitor the level of the water inside. The lower probe ends just above the heating element. When the machine is fired and filled for the first time, the brain only switches on all heating elements, when the lower probe detects water. During filling up, the coffee boilers fill quicker than the steam boiler because filling starts immediately when the water connection is opened and the coffee boilers are smaller. When the lower probe in the steam boiler detects water the elements inside the coffee boilers are already submerged. This system ensures the elements cannot be turned on while not being cooled by surrounding water. If the steam boiler level would ever fall under the safety probes tip, the machine shuts down completely with the led at group lever or touch pad blinking as an alarm. This alarm mode is also activated when one of the group solenoids or the filling solenoid is activated continuously for longer than 2 minutes. The machine can be re-set by switching it off and on again.
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. All temperature settings 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. When this switch detects too high a temperature, it will disconnect power to the element. The steam boiler is equipped with a safety valve. The coffee system, including the heat-exchanger, is equipped with an expansion valve. The group solenoid valve may act as a second expansion valve, rated at 15 bar, in the event the original expansion valve would fail.
The Slim Jim has a wide range of visual options meaning that everyone can now have their own bespoke commercial espresso machine: be it an aspiring espresso bar owner or a chain of shops.
Many different, visually defining parts can be chosen; legs, front panels, side panels, cup rails, colours, awnings, colour of knobs/handles, group caps, and so forth.
Furthermore, all parts are interchangeable allowing the Slim Jim to evolve or adapt over time.
At Kees van der Westen, we quietly craft exceptional espresso machines for those who appreciate the art and science of making great coffee. We spare no details when it comes to designing and engineering our machines. Down to the smallest parts we design for delight. Meaning we aim to bring joy to everyone involved in our espresso journey. From the knowledgeable distributor to the passionate barista and from the handy maintenance technician to the people standing in line ordering their coffee treat.
