Krups Coffee Roasters: espresso in a slice of good pressure

The popular Krups coffee machines with pressures over 15 bar allow small coffee preparation. Commonly called “expresso” coffee. There is no consensus about the origin of the term. It may have been formed from the French word “expres” especially for you . It is also believed that it is based on the Italian word espresso – quick.

Author: Andrei Kashkarov, St. Petersburg

A basic primer with a coffee pot in hand

One can argue endlessly about the origin of this word in American, but the point remains the same: thanks to industrial portable coffee machines, fine coffee can be made at home, and it will be as good as in the bar.

For making espresso coffee one can use finely ground mixtures of strongly roasted coffee beans or special capsules. Their high-pressure treatment with boiling water or steam provides a high extraction degree of essential oils and aromatic substances.

The peculiarity of coffee obtained in this way is the golden foam, which contains gelatin-like substances with a low degree of sedimentation.

A special type of coffee drink is the so-called “cappuccino”, where hot frothed milk is added to the coffee. Preparation of these drinks requires a special type of coffee maker.

Krups coffee machines are a group of technically complex and reliable household coffee-making devices, which can not be compared with drip filter coffee makers. Regardless of the brand, coffee makers and coffee machines can be divided into two categories: with and without a pressure pump.

The constructive diagram of the coffee machine is shown on fig. 1.

Rice. 1. How a coffee maker works

According to this scheme, it is not difficult to imagine the whole path that water takes before it goes straight to the cup. The heat from the heating element 1 is transferred to the water 2 filling the tank 3 which is closed by the sealing lid 4. The lid has a safety valve to release excess pressure. The steam-water mixture formed in the tank enters the filter 5, which contains a portion of ground coffee.

The prepared speciality coffees flow into the drip tray 6. Tray, on which the flask stands, may have a built-in heating element to keep the beverage hot. For aeration foaming of milk in the preparation of “cappuccino” is a special nozzle 7, steam to which the tube 8 when you open the faucet 9.

This tap also serves to release excess pressure when the appliance is finished. The disadvantage of this type of coffee machines is the long time it takes to produce coffee, because all the water in the tank must be heated and boiled. The pressure rises to a maximum of 5 bars.

As a rule, such a scheme is used in compact coffee machines with a small tank of the models Ufesa CE 7110 Troppo, Krups Espresso Mini 963, Krups II Primo 972, Unit UCM-810, DeLonghi BAR 6.

The presence of a pressure pump allows you to get a higher pressure level from 9 to 17 bar, depending on the power of the pump without having to boil the entire volume of water poured into the coffee maker tank. But even here you can’t be sure that the 15 bar pressure stated on the packaging of the coffee machine is actually the same. It often happens that this is no more than an advertising trick of the producer and intermediary, most likely the real pressure of a household coffee machine does not exceed 7-9 bar.

One diagram of a coffee machine with a pressure pump and a boiler, a special vessel for generating steam, is shown in Fig. 2.

Figs. 2. Pressure pump coffee maker

A portion of water from the water tank 1 is pumped with a delivery pump 2 into a boiler 3, where water is boiled and steam forms. Inside the boiler there is a heating element Boiling water 4 or a steam-water mixture enters the filter with the ground coffee 5. To prepare “cappuccino”, there is a tube 6 of steam exhaust from the upper part of the boiler, where the steam tap 7 is made. Krups Novo Compact 989, Krups Novo Compact Latte 882, Krups Espresso F 880 are this type of coffee machine.

In coffee machines with pressure pump, the heat block, which is nothing else but a heating element with a highly developed spiral shaped inner surface, is used more and more often instead of the boiler.

Depending on the mode selected, the power delivered to the water flowing through the channel labyrinth of the thermoblock may be enough only to bring water to the boiling point espresso mode , or increased to achieve intense evaporation steam mode . The water heats up very quickly because of the large surface area of the heat exchanger, which reduces the preparation time of the coffee.

Krups offers a dual pressure pump machine which allows simultaneous production of espresso and cappuccino models BAR-M 200, BAR-M 110 and similar .

A special IFD Instant Froth Dispenser is used for making cappuccino. Contrary to the above-mentioned diagrams, where steam is poured into an external milk container, here the milk is poured beforehand into a special container inside the coffee machine and at the outlet of the spout IFD. A foamy milk is formed which flows directly into the cup.

The new generation Krups KR1006, KR5006, KR 5000, KR 2106, KR2110 of 1500 Watt capacity and 15 bar steam pressure have an energy saving mode after 20 minutes of “idle time” and use coffee capsules to produce “expresso.

Design of coffee maker

Let’s take the example of the Espresso F 880 for a coffee machine with a pressure pump and a thermoblock. It is shown on photo 3.

Photo 3. Krups Espresso F 880

The 880, shown below, was preceded by the similarly designed 988. The internal construction of the coffee machine is shown in Fig. 4.

Fig. 4. Internal Structure of a Coffee Maker

Note on Fig. 4.

1 – foot, 2 – base, 3 – body, 4 – top lid, 5 – water tank, 6 – tank handle, 7 – tank lid, 8 – stainless steel top panel, 9 – power cord, 10 – water filter, 11 – gasket, 12 – valve gland, 13 – front panel, 14 – stainless steel decorative cover, 15 – mode switch knob, 16 and 17 – indicator lamps, 18 – power switch, 19 – grid, 20 – water drain for spilled water on the base, 21 – water collection tray.

Your coffee maker also comes with a ground coffee filter, the components of which are shown in Fig. 5.

Rice. 5. Preground coffee filter components

1 – filter holder, 2 – gasket, 3 – gasket, 4 – disc, 5 – sieve, 6 – measuring spoon. Photo of the coffee filter shown in Fig. 6.

Fig. 6. Photo of the coffee filter

The design of the filter holder in modern coffee machines is improved in comparison with former models, for example, the model 988 Krups, and allows to carry out automatic sealing of the ground coffee poured into the filter without changing the filter when attaching the filter to spout by turning a limb to set the number of cups of coffee, and after coffee-making it is easy to free the filter from coffee grounds, which are ejected in the form of a dense cylindrical briquette.

An electric circuit diagram of the coffee machine is shown in Fig. 7.

Figure. 7. The electrical circuit of the coffee machine

Note for Fig. 7.

1 – circuit breaker, 2 – light indicator light, 3 – temperature indicator light, 4 – interference filter, 5 – switches, 6 – pressure pump, 7 – pump safety switch, 8 – fuse, 9 – heating element, 10 – thermostat coffee mode , 11 – thermostat steam mode .

Technical data of the Krups F 880

Total connected load of the machine is 1050 W, the solenoid injection pump generates 14 to 17 bar. Water tank capacity of 1.1 l, which is equivalent to approx. 22 small coffee cups. The capacity of the drip tray is 0.25 litres. Switching temperatures of thermostats: Hot water thermostat coffee mode – 112 °C, steam thermostat steam mode – 140 °C, safety thermostat reacts at +206 °C.

Typical malfunctions and remedies

B Tab. Table 1 shows typical problems with this coffee machine type and helps to remedy them.

Table 1. Typical malfunctions of this coffee machine type and troubleshooting

Problem	The reason	Fix the problem
Coffee not hot enough	1. Heating is not finished 2. Thermostat faulty 3. Grinding quality does not correspond to the beverage to be prepared	1. Wait until the heating indicator light goes out. 2. Replace the thermostat 3. Coffee must not be ground too finely. To use ground coffee for ESPRESSO coffee machines
The coffee is too hot	The thermostat is loose or defective	1. Tighten the screws that fix the thermostat. 2. Replace the thermostat
Coffee machine does not work no heat-up when plugged in	Thermostatic block defective	Replace thermoblock
Coffee does not come out of the spout	1. The delivery pump is defective 2. Channels in the thermoblock are clogged 3. There is limescale in the coffee machine ducts	1. Check and, if necessary, replace the pressure pump 2. 5 Clean the channels in the thermoblock 3. Descale the machine
Printed circuit board malfunction in “Steam” mode	1. The circuit board is defective 2. Incorrect pins in the wiring to the pump 3. 4 Mode switch defective	1. Check and, if necessary, replace circuit board 2. Restore the correct contact order 3. Replace the mode switch
Light indicators do not turn on	1. Indicator lights not securely fastened in cartridges 2. The warning lights are faulty 3. Printed circuit board is defective	1. Check that the indicator lights are fixed 2. Replace indicator lights 3. Replace the circuit board
Water is continuously leaking from the steam pipe while the coffee machine is operating or after it has been switched off	Leak through the ceramic discs	Clean or replace ceramic discs
Coffee is leaking around the periphery of the filter holder	1. The O-ring on the metering unit is damaged 2. The seal ring is contaminated with ground coffee particles	1. Replace the O-ring 2. Clean the o-ring
Water leaking from the coffee machine	1. The seal on the water basin is damaged 2. Leaky seating of the connection tubes 3. The dispenser seal is damaged 4. Seals are damaged	1. Check and if necessary replace the reservoir seal 2. Check the tube seating 3. Check and if necessary replace the seal 4. Check and, if necessary, replace the seals
Noise in the discharge pump	1. The water tank is empty 2. The water tube is jammed	1. Replace reservoir 2. Remove tube pinch
Insufficient foaming during milk aeration	1. Steam pipe or nozzle is clogged 2. Milk is in the cold container	1. Clean tube or nozzle 2. Preheat milk container before aerating

Monthly maintenance of the coffee machine

For trouble-free operation of the coffee machine every 2-3 months depending on the hardness of the water used it is necessary to remove the scale formed in it. Use a solution of citric acid in the proportion of 2 teaspoons acid in 0.5 liters of warm not necessarily boiling water.

The ground coffee spout and filter must be cleaned after each use. If heavily soiled, clean the sieve and the sealing ring with a brush. If the steam nozzle is clogged, clean it with a needle.

Disassembling the coffee machine

When disassembling the device, first remove the tray to collect spilled liquid, then the lid of the water tank and the tank itself.

The procedure for dismounting the base is illustrated below.

First disassemble the base of the coffee machine by turning the appliance upside down and removing the five screws, then undo the four catches that hold it in place. Remove the tube that connects the reservoir and the delivery pump. Unscrew two more mounting screws.

Then remove the mode switch knob on the front panel and unscrew the two fixing screws that are lodged in the steel cover. Remove the front plate by pressing out the four catches that hold it in place. Only then remove the cover.

Dismantle the tank mount according to fig. 8.

Fig. 8. Dismantle coffee tank mount

According to pic. 8 unscrew the 5 mounting screws 1. Unclip locking catches 2 and remove the lid of the reservoir. After removing the base, shown in this picture. 9.

Fig. 9. The method of removing the base of the coffee maker

Then disassemble the delivery pump the illustration is shown in Fig. 10.

Rice. 10. Disassembling the delivery pump

Remove the water tank lid and disconnect the water pipe from the water tank to the delivery pump 1 . Disconnect the electric cables. Pushing the pump out of the seat of the lower support bracket 2 . Pressing the pump, release it from its mount 3 .

Removing the heating element is shown in Fig. 11.

Rice. 11. Removing the heating element

After removing the upper lid, you put the machine on its side. Unscrew the steam nozzle, remove the grid and gasket. Then loosen the two fixing screws, supporting the heating element until it is completely free.

Reassembling the machine

Reassemble in reverse order, paying attention to the following. When assembling the thermoblock it is important to install the O-rings properly, otherwise you can kiss the “expected steam” goodbye.

When assembling the delivery pump it is important to ensure that the connection pipes are fitted snugly.

Ceramic discs and washer are lubricated with food grade grease.

When assembling the water tank, special attention must be paid to the seals.

After following these simple instructions for reassembly, the Krups F 880 is ready for testing again.