Choosing the right coffee machine?

Anybody looking for a coffee machine for home use will probably have been overwhelmed by the vast number of machines available to purchase.

There are numerous types of machines available from pump coffee machines, automatic coffee makers, bean to cup coffee machines and now even outdoor coffee machines

The best method for choosing the correct coffee machine for you is to examine your lifestyle, the type of coffee you want and be truthful about how complicated you wish your home use coffee maker to be, some home use coffee makers can be hard to fathom!

It is also a good idea to know what you want to spend, the cost of the various machines varies significantly from the small hand held coffee machines - which make great gifts - to the impressive £2000 plus fully automatic coffee machines offered by the likes of Siemens coffee machines which are suitable for use in busy coffee chains, an unlikely gift even from the most generous.

It is a good idea to look at the reviews and try to understand the capacity of the coffee machine prior to buying one. Here follows a few pointers towards certain coffee makers.

Steam-driven coffee machines operate by pushing water through the coffee grinds using steam or steam pressure. The first coffee makers were steam models, produced when a boiler was piped to four group heads so that multiple types of coffee could be made at the same time. The same design is still used today in low-cost consumer coffee makers, as it does not need to contain moving parts. Many low-cost steam-driven units are sold in combination with a drip-coffee machine.

Piston-driven coffee machines or lever driven machines were developed in Italy in 1945 by Achille Gaggia, founder of Gaggia coffee machines. The design normally uses a lever, pumped by the user, to pressurize hot water and send it through the coffee grinds. The act of producing a shot of espresso is colloquially termed pulling a shot, because these lever-style espresso makers required pulling a long handle to produce a shot

There are two types of lever machines; spring piston design and manual piston. With the manual piston, the operator directly pushes the water through the coffee grinds. In the spring piston design, the user works to tension a spring, which then delivers the pressure for the espresso (usually 8 to 10 bar).

Pump-driven coffee machines are a refinement of the piston coffee maker, which has become the most popular design in professional coffee shops. Instead of using manual force, a motor-driven pump provides the force necessary for espresso brewing. DeLonghi coffee machines are themost popular manufacturers for this type of coffee machine.

Professional coffee shop machines or some high-end home coffee machines are often attached directly to the water supply on the site; lower-end home coffee machines have built-in water reservoirs.

Some home pump espresso machines typically use a single chamber both for boiling water up to brewing temperature, and to boil water for steamed milk. As the temperature for brewing coffee is sometimes less than the temperature for making steam, the espresso maker requires time to make the transition from one mode to the other. Water for brewing can pass through a heat exchanger (taking some heat from the steam, without rising to the same temperature). In some coffee machines, for coffee shops or domestic use, water for brewing is heated in a separate chamber.

Espresso machines which contain the addition of sensors, valves, pumps, and grinders to automate the brewing process generally are referred to as automatic.

Semi-automatic espresso makers are automatic in the sense water is delivered by a pump, rather than manual force and the remaining brew pressure in the basket is dissipated with a three way valve.

Automatic coffee makers add a flowmeter inline with the grouphead. When the pre determined amount of water has passed through the flowmeter, the pump is automatically turned off and brew pressure let out through a three way solenoid valve.

Super-automatic machines operate by also automatically grinding the coffee beans, tamping it, and extracting; all any user needs to do is fill the beans, and if the machine is not plumbed in a water line, add water to a reservoir. Additionally, models contain an auto milk frothing and dispensing feature.

Recently air-pressure driven portable espresso makers have come onto the market. A Handpresso is a portable coffee machine. It works by pumping air at very high pressure (16 bar) into an intermediate chamber. Hot water is then poured into a small reservoir, which can contain boiling water for individual cups of espresso coffee. Ground coffee is inserted on top of the water reservoir and a portafilter is screwed on the top of the water container. The machine is now turned around and the pressure from the storage chamber is released into the water container. The high pressure pushes the water through the coffee pod and into the cup, which should be put underneath the coffee maker. When the required amount of espresso is brewed, the pressure is released from the water container and the infusion process stops.