Coffee machine
A fully automatic coffee machine is a coffee machine that can produce various types of coffee fully automatically using the espresso method . This is not to be confused with the classic espresso machine .
In addition to making coffee, many devices can froth milk with the help of steam . Some models produce the milk foam for a cappuccino or latte macchiato using a cappuccinatore . This automatically sucks in milk and processes it into milk foam. The devices are equipped with cleaning and descaling programs that require the user to supply the necessary chemicals (and those offered by the manufacturer) at regular intervals. In order to avoid premature calcification of the machine and to remove unwanted substances from the water used, the manufacturers equip their devices with replaceable water filters .
history
Fully automatic coffee machines have evolved from self-service machines , where they can be found as vending machines. As there was hardly any demand for ready-made soups or sweet drinks, the output concentrated more and more on coffee products.
In the 1960s Otto Bengtson invented a fully automatic coffee machine with an integrated grinder in Berlin , which was marketed from 1964.
The Swiss engineer Arthur Schmed from Rüti developed another machine at the end of the 1970s, which adopted the principle of pressure and the short brewing time of the espresso machine and also automated the preparation. After two years of work and development, around 1980 he produced the first fully functional prototype of a fully automatic coffee machine. In 1985 the Solis company presented the Solis fully automatic espresso machine as a world first at a trade fair.
Working principle
Simple filter coffee machines only consist of a heating element that heats water and directs it over the coffee powder in the filter. A fully automatic machine, on the other hand, consists of a grinder , the hot water heater ( flow heater ), a pump and the heart, the brewing group with drive. Depending on the manufacturer, the brew group is permanently installed in the device or can simply be removed from the device for cleaning and maintenance purposes. The control unit also controls the facilities for hot water preparation and milk frothing if necessary. It also allows you to set the cup size, brewing temperature, water hardness (to define the descaling cycles ) and, if necessary , the amount of powder (strength of the coffee).
The grinder chops the beans right before the brewing process. Most fully automatic machines offer the option of setting the exact degree of grinding, whereby the intensity can be determined individually. The beans are first roughly chopped in the grinder and then get into narrower areas, where they are processed further and further down to the desired degree of grinding. Modern devices have conical or disc grinders made of ceramic or hardened steel.
The biggest difference between coffee from a conventional filter coffee machine and a fully automatic machine is the aroma , which can best develop through pressure . With conventional machines, the coffee quickly becomes too bitter because no pressure is generated and more and more bitter substances and tannins get into the coffee due to the long contact with the coffee powder . If the coffee is brewed for too long, it will be inedible. During the brewing process, which in a fully automatic coffee machine usually takes less than 30 seconds for a cup of coffee, more essential oils and aromas are released due to the pressure of approx. 7.5-9 bar, but less caffeine due to the short brewing time . Tannic acids and bitter substances. That makes the coffee more digestible and aromatic. The crema locks the aromas in the hot coffee / espresso until they dissolve. This happens when the coffee / espresso cools down. The longer the crema is retained, the longer the good and aromatic taste of the coffee is retained.
Pressure is one of the most important requirements for a good espresso. You need a certain pressure for an espresso. This is approximately between 7.5 and 9 bar. This pressure ensures that the aromas of the espresso or coffee beans can develop best. With most fully automatic machines, the maximum pump pressure is approx. 15 bar. However, the maximum pressure of a pump only describes the maximum performance of the pump, not the pressure with which coffee is actually brewed. In large espresso machines, the brewing pressure builds up because the pump presses the brewing water against the compressed coffee grounds. With the usual fully automatic coffee machines, a pressure control valve is also built into the brewing group in order to ensure even pressure even with different degrees of grinding and filling quantities. A pressure of approx. 9 bar has proven to be a good guideline, which means that the aroma components are optimally dissolved from the coffee grounds.
After the coffee has been prepared, the ground and pressed bean residues, also called pomace , are transported from the brewing group to a collecting container with the help of a mechanical device, which must be emptied and cleaned regularly.
Furthermore, a milk frothing nozzle is integrated in most machines these days. With many models it is even possible to use this to produce hot water for tea. Many companies offer the option of buying a cappuccino nozzle with which you can create milk foam by simply turning it. This then draws the steam from the fully automatic machine, sucks the milk out of a container and foams it through a nozzle into the cup below. Most fully automatic machines only have one heating circuit, so making a latte macchiato , for example, can take a few minutes, because after the milk foam has been produced, the heating circuit has to be cooled down again in order not to burn the subsequent coffee / espresso. With modern devices this takes about 10-30 seconds. Some high-quality devices have two separate heating circuits and enable the simultaneous preparation of milk foam and coffee or espresso without delay.
Device types and manufacturers
Fully automatic coffee machines are roughly divided into those for gastronomy and those for home use. The construction of most devices is characterized by the excessive use of plastic parts. For decorative reasons, the plastic parts are fitted with some metal trim on the surface, or large areas are provided with metallic paint or chrome plating. Colorful displays and LED lighting are also part of the presentation of the devices.
Some manufacturers also manufacture their fully automatic machines for external companies in the household appliances sector. The inner workings of these are identical to the relevant models from the original manufacturer and only differ in the housing design. Brands of fully automatic coffee machines include: Miele , WMF , Melitta , Bosch , Siemens , Jura , Philips , Saeco , Solis , De'Longhi , Nivona , Thermoplan , Franke , Schaerer , Cafina , Egro and HGZ .
Durability and service
Fully automatic coffee machines are produced by various, mostly Italian and Swiss manufacturers. The price range of the products on offer is from 200 euros upwards, whereby the retail price primarily indicates the number of equipment features, but does not allow any conclusions to be drawn about the quality of the installed parts or the durability of the machine as a whole.
In 2013, a Saeco fully automatic machine became the subject of litigation. A customer was mistaken because the machine, for which he had paid 849 euros, according to his complaint, did not produce proper milk foam. The district court dismissed the lawsuit, as no other (fully) machine in this price segment was better in this regard; the customer gets the quality that he can expect for this purchase price.
The Westdeutsche Rundfunk took up the topic in its television series "Servicezeit Technik" on August 4, 2005 and came to the conclusion that the fully automatic coffee machines have so far been built in a quality that can be achieved after around 1500 cups (in most cases this corresponds to a usage time of around two years and thus the legally prescribed warranty period) are increasingly susceptible to repair. The customer service that then began is again partially bad, which drew the attention of Stiftung Warentest , which complained about undetected errors, excessive service prices and too long downtimes of the devices.
Fully automatic coffee machines are also made available or rented by various providers in a full service concept. These offers are aimed primarily at commercial customers. The risk of the durability of the machine and the supply of spare parts is assumed by the system provider who carries out repairs on site. A change of device class is also possible with some providers in order to adapt the existing system to the changing requirements of the customer. This convenience has its price, of course, but it takes you away from the worries that the failure of a fully automatic coffee machine can otherwise bring with it.
Coffee beans
Not every coffee bean is suitable for a fully automatic coffee machine. There are already differences when it comes to refining the coffee. In some European countries, additives are added to the roasting process. In Spain it is common to add sugar. This type of ready-roasted bean can clog and ruin the grinder. Furthermore, extremely cheap coffee beans can also contain small stones that may damage the grinder.
Food hygiene
The cleaning of the technically complex devices for private households is not trivial with every model. This is sometimes neglected in the catering industry . In particular, frothed milk can be contaminated with pseudomonads . The official food control in Germany therefore regularly carries out food controls and analyzes the samples in state inspection offices.
Web links
Individual evidence
- ↑ Walter Jäggi: The engineer who changed our lives. In: wayback.archive.org. February 9, 2007; archived from the original on May 11, 2013 ; accessed on November 15, 2016 .
- ↑ Solingen: Richter wants comparison in the cappuccino dispute. In: Solinger Bote
- ↑ Legal foam battle over a coffee machine. In: welt.de
- ↑ Stiftung Warentest: Test Espresso Machine Customer Service
- ↑ Nora Jakob: Calcified, moldy and full of germs - "You have to look after fully automatic coffee machines like a pet" , Wirtschaftswoche , April 30, 2015
- ↑ Sebastian Dubielzig: Dirty Machines: Bacteria in Coffee , NDR , November 13, 2017
- ↑ Sabine Horlacher: Milk foam from coffee machines - always delicious? - A report from our everyday laboratory work , December 8, 2009
- ↑ Sabine Horlacher: Foamed milk from vending machines - a review of 4 years of investigative activity , February 18, 2014