Our guide to Choosing an Espresso Machine June 25 2014
When purchasing their first serious espresso machine, people usually choose either a semi automatic or automatic model.
To clear up some confusion that may exist over nomenclature used by consumers, vendors, and advertisers....
- Semi Automatic Machines. These feature an automated pump, automated temperature controls for the boiler, and activation switches to engage and disengage the pump. That's what makes it "semi-automatic" - you decide when to turn the pump on and off.
- Automatic Machines. These feature a pump, automated temperature controls for the boiler, and automated (and frequently programmable) preset water volumes selected by pressing a button. That's what makes it "automatic".
There are actually many subclasses of machines in the semi automatic and automatic machine categories, but really, only three major ones.
- Single Boiler, Dual Use Machines. This is by far the most common type under £1,000. This type of machine has one boiler and two thermostats (or more) inside. One thermostat controls the water temperature for brewing coffee. The other thermostat is set at a higher temperature, to produce steam for steaming milk. The machine transitions from one thermostat to the other when you flip a switch or press a button. These machines cannot brew and steam at the same time.
- Single Boiler, Heat Exchanger Machines. These machines are more common above the £1,000 price point. A big boiler maintains water at around 115C or higher, ideal for producing steam. Brewing water makes its way to the grouphead through a coiled tube inside the boiler. As it is drawn from the reservoir, through the coiled tube, it flash heats up to (hypothetically) ideal brewing temperatures. The coiled tube is the heat exchanger. You can steam and brew at the same time on these machines.
- Dual Boiler Machines. Feature two independent boilers (or a boiler and a thermoblock), one that maintains water at brewing temperatures, one that maintains water at steaming temperatures. You can steam and brew at the same time on these machines.
Semi automatics are available in all the three subclasses listed above, and as mentioned at the top of this page, automate a lot of things for you while still giving you ultimate control over how your shot of espresso will progress.
Because you decide when to activate the pump and when to turn it off, you control the total water flow for every shot you make. Why is this important? There may be cases where you build a shot and notice it's pouring very slowly but looking very good. With an automatic machine, the machine decides when to end your shot - and it may end the shot too soon. On the semi auto, you can just let the pump run longer before you hit the switch to stop things.
Automatics are called so because they automate the delivery of water for you. You press a button and the machine delivers a predetermined volume of water, more or less the same amount every time. (If you grind finer or pack more coffee into the basket, the overall extraction will be less.) So you load up your filterpan with coffee, tamp it, lock it into your machine, press a button, and for all purposes, you can walk away at this point. The machine will stop brewing once its internal volumeter hits the preprogrammed amount.
These machines typically feature four brewing buttons or switches: one shot short, two shots short, one shot normal (long), two shots normal (long). A fifth button, usually found to the right of the four preprogrammed switches, is the aforementioned "on till you press me again to turn off" semi-auto button.
On most of these machines (though not all), you can program in any volume you want for each of the brewing buttons. If you want, you can set the far left button (usually single shot short) to push 10 ounces through the coffee if that's your desire.XXXX