Espresso Machines

Since their invention in 1901, multiple machine designs have been created to produce espresso. Several machines share some common elements. Varying the fineness of the grind, the amount of pressure used to tamp the grinds, or the pressure itself can be used to vary the taste of the espresso. Some baristas pull espresso shots directly into a preheated demitasse cup or shot glass, to maintain a higher temperature of the espresso. An espresso machine may also have a steam wand which is used to steam and froth liquids, to include milk, for beverages such as the cappuccino and latte.

Steam Driven
A steam-driven unit operates by forcing water through the coffee by using steam or steam pressure. The first espresso machines were steam types, produced when a common boiler was piped to four group heads so that multiple types of coffee could be made at the same time. The design is still used today in low-cost consumer machines, as it does not need to contain moving parts.

Piston Driven
The piston, or lever, driven machine was developed in Italy in 1945 by Achille Gaggia, founder of espresso machine manufacturer Gaggia. The design generically uses a lever, pumped by the operator, to pressurize hot water and send it through the coffee grinds. The act of producing a shot of espresso is termed pulling a shot, because these lever-style espresso machines required pulling a long handle to produce a shot. There are two types of lever machines; manual piston and spring piston design. With the manual piston, the operator directly pushes the water through the grounds. In the spring piston design, the operator works to tension a spring, which then delivers the pressure for the espresso (usually 8 to 10 bar).

Pump Driven
A refinement of the piston machine is the pump-driven machine, which was introduced in 1961, and has become the most popular design in commercial espresso bars. Instead of using manual force, a motor-driven pump provides the force necessary for espresso brewing. Commercial or some high-end home machines are often attached directly to the plumbing of the site while lower-end home machines may have built-in water reservoirs. Four variants exist in home machines. They are a single boiler, a single boiler with dual use, a heat exchanger and a dual boiler.

Air Pump Driven
In recent years air-pump driven espresso machines have emerged. These machines use compressed air to force the hot water through the coffee grounds. The hot water is typically added from a kettle or a thermo  flask. The compressed air comes from either a hand-pump, N20 or CO2 cartridges or an electric compressor. One of the advantages of the air-pump driven machines is that they are much smaller and lighter than electric machines. They are often handheld and portable.

Automatic espresso machines have pumps, sensors, valves, and grinders to automate the brewing process. Automatic machines also automate the brewed volume (hence indirectly brew time). They do this by adding an in-line flow meter to the group head so that when the programmed amount of water has passed through the meter, the pump turns off. Grinding and tamping are still manual.

Semi-automatic espresso machines use a pump rather than manual force to deliver water. The remaining brew pressure in the basket is released via a three-way valve. Manual or semi-automatic machines offer more control of shot quality. Because when to cut the shot (brew time) is a critical variable, which is often adjusted shot-by-shot, semi-automatic machines are often preferred over automatics, though some machines are automatic. Manual machines are more popular in Europe, where it is more common to drink straight espresso.

Super-automatic espresso machines automatically grind the coffee, tamp it, and extract the espresso shot. The operator only has to fill the bean hopper and, if the machine is not connected to a water line, add water to a reservoir. Some models contain an automated milk frothing and dispensing device. Super-automatic machines take away the ability to manually tamp and grind the coffee, which may affect the quality of the espresso. Most super-automatic machines are more compact than a machine with a separate grinder.

Commercial establishments generally use semi-automatic machines with several group heads. These are much larger than consumer models and able to produce espresso shots more quickly. Many commercial machines can function in an automatic mode.

Stove Top
Moka pots, also known as stove top espresso makers, are similar to espresso machines in that they brew under pressure and the resulting brew shares some similarities, but in other respects differ. Due to their use of pressure and steam for brewing, comparable to all espresso prior to the 1948 Gaggia, they are accepted within broader uses of the term, but distinguished from standard modern espresso machines.

Moka pots are similar to espresso machines in that they brew under pressure, produce coffee with an extraction ratio similar to that of a conventional espresso machine, and, depending on bean variety and grind selection, moka pots can create the same foam emulsion known as crema that conventional espresso machines can.

Moka pots differ from espresso machines in that they brew under substantially lower pressure – 1.5 bars rather than 9 bars – and use hotter water – a mix of boiling water and steam at above 100°C (rather than 92°–96° of espresso machines), similar to early steam brewing machines.

The bottom chamber contains the water. The middle chamber is a filter-basket and sits within the bottom chamber holding the ground coffee. The top chamber, with a metal filter, screws onto the bottom chamber. When the pot is heated on a stove, the pressure from the steam in the bottom chamber forces the water through a tube into the filter-basket, through the ground coffee, the metal filter, and it then funnels into the top chamber where the coffee is then ready to serve. They are commonly found in Italy, Spain and Portugal. Compliments of Wikipedia, the free encyclopedia.

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Espresso

Espresso is a concentrated beverage brewed by forcing a small amount of nearly boiling water under pressure through finely ground coffee beans. Espresso often has a thicker consistency than coffee brewed by other methods, a higher concentration of suspended and dissolved solids, and crema (foam). As a result of the pressurized brewing process the flavors and chemicals in a typical cup of coffee are very concentrated. Espresso is the base for other drinks, such as a latte, cappuccino, macchiato, mocha, or americano. Espresso has more caffeine per unit volume than most beverages, but the usual serving size is smaller—a 30 mL (1 US fluid ounce) shot of espresso has 40 to 75 mg of caffeine, which is less than half the caffeine of a standard 240 mL (8 US fluid ounces) cup of drip-brewed coffee. A professional operator of an espresso machine is a barista, the Italian word for bartender.

Espresso roast

Espresso is a coffee beverage and brewing method, it is not a specific bean, bean blend, or roast level. Any bean or roasting level can be used to produce authentic espresso. For example, in southern Italy, a darker roast is generally preferred; but farther north, the trend moves toward slightly lighter roasts. Outside of Italy a wide range of roasts are popular.

Brewing process

Espresso is made by forcing very hot water under high pressure through finely ground, compacted coffee.This process produces an almost syrupy beverage by extracting both solid and dissolved components. It also produces the definitive crema, by emulsifying the oils in the ground coffee into a colloid, which does not occur in other brewing methods. There is no universal standard defining the process of extracting espresso, but there are several published definitions which attempt to place constraints on the amount and type of ground coffee used, the temperature and pressure of the water, and the rate of extraction. Generally, one uses an espresso machine to make espresso. The act of producing a shot of espresso is often termed “pulling” a shot, originating from lever espresso machines, which require pulling down a handle attached to a spring-loaded piston, forcing hot water through the coffee at high pressure. Today, however, it is more common for the pressure to be generated by an electric pump.   Compliments of Wikipedia, the free encyclopedia.

Tips For Buying The Right Espresso Machine

Guest Post by Jeremy Winters

A little under decade ago, an espresso machine was reserved for coffee shops, hotels and restaurants. This was to some extent due to the huge cost as well as the reluctance among individuals to make them household items. Nevertheless, times have changed and these types of devices are currently available in numerous houses and they are growing to be as prevalent as other home appliances such as microwaves and fridges.

For that reason, coffee lovers will not any longer be forced to get out of the home to buy their favorite drink. They’ll be able to fix it in the comfort of their own personal homes employing these machines. To some extent due to the economic crisis, Starbucks is ready to close a number of its shops and with this you should expect to see even more espresso makers in people’s homes.

You will find four primary categories of these machines – manual, semi-automatic, automatic and fully automatic. The difference between these categories is that the higher you climb up (from manual to fully automatic), the less you are going to be involved with the process of fixing the espresso. With the manual unit, you will be required to do a great deal of the work yourself.

With fully automated machines, all you have to do is pour the amount of coffee beans you prefer and water then voila, the unit will prepare your espresso automatically. You’ll want to realize that the prices of these machines increase as you move from manual to fully automatic.

The steam feature of an espresso machine is one of the most crucial features of your machine. That is because espresso cannot be made without steam. The machine typically changes the water into steam. This steam is then passed through the coffee grounds where it changes them into espresso. The more robust this steam is, the stronger your espresso. When you are getting a machine, be certain you inquire about the steam feature and its strength. This is because there are actually many espresso makers which don’t use a strong force of steam and will wind up disappointing you in the quality of espresso that they produce.

Finally, you will want to consider your budget, and that is because these machines vary in cost. This variation can be attributed to several factors including brand name among other issues. Basically, you can get some basic ones for as cheap as $30 while you’ll find others that have prices as great as $6000. However, these costly models are frequently for large scale commercial purposes and if all you are searching for is one for home use, you will not need to have such a costly espresso machine.

Are you looking for the best espresso machine? Read more at Espresso Machine Reviews to learn more about coffee and picking the perfect machine.