What does "Semi-automatic" and "super-automatic" mean?
A semi-automatic machine gives you control of making a great espresso drink. You grind the coffee beans, tamp them down in a portafilter, and control how long the machine brews an espresso shot. On most machines you do this by pressing a button or lifting a lever, then turning it off when the shot has reached the right volume.
A super-automatic machine controls all aspects of making espresso: grinding, tamping, pulling a shot, and steaming milk. They are very convenient, but typically the quality of the espresso and final beverage is not as good as that from a semi-automatic machine.
What are the differences between the boiler types?
The first thing to consider when purchasing an espresso machine is boiler type. Steaming milk requires a higher temperature than pulling an espresso shot, so some boilers allow you to do both at the same time while others require a waiting period when switching between the two modes.
There are three main types of espresso machine boilers:
Single Boiler | Single boiler espresso machines have one boiler for steam production and espresso brewing. These machines have 2 thermostats to separately control the steam and brew temperature.
While you aren’t able to steam milk and brew coffee simultaneously, it’s quite simple to get the rhythm of heating to steam mode, frothing your milk, cooling the machine down, preparing your espresso and then pouring your latte or cappuccino.
Heat Exchanger | Heat exchange machines have a single boiler that is always set to steam temperature. A metal tube runs through the boiler, which flash heats the water at around 200 degrees to the grouphead. This clever design delivers fresh water from the pump to the grouphead, and mimics the capabilities of a double boiler machine.
With a heat exchanger machine, dry steam and hot water are available at all times, without the need to flip any switches or switch any modes. Also, you are able to steam your milk and brew your coffee at the same time, leading to the freshest, professional-style latte.
Double Boiler | Double boiler espresso machines have one boiler each for steam and espresso. You can steam and pull shots simultaneously. Additionally, the steam boiler has a dedicated power switch, which gives the user the option to provide power only to the group head boiler if milk steaming won’t be necessary. Double boilers typically control the temperature digitally for the most consistent temperature. If you want the best, consider a double boiler.
Do I need a PID?
A PID (Proportional Integral Derivative) controller closely monitors and electronically regulates the water temperature at the brew group. A PID sends short bursts of power to your boiler, keeping the temperature within a very narrow range. With a machine like the Izzo Duetto, you can control the temperature to within 1 degree of accuracy. Heat exchangers cannot be used with a PID, and instead rely on a mechanical pressurestat to regulate temperature. Single boilers can have PID control, and are an upgrade option on machines like the Quick Mill Alexia.
PIDs are not required for a good espresso shot, but they do allow you to precisely dial in your brew temperature. This is especially important for single origin espressos and straight shot enthusiasts.
If I buy a single boiler machine, do I need to “temperature surf”?
If you’ve done any online research about the Rancilio Silvia and other single boiler machines, chances are you’ve come across talk of something called “temperature surfing.” Temperature surfing refers to a method of regulating the temperature of the brew water. It requires determining the precise water temperature relative to the machine’s position in the boiler heating cycle and timing the preparation of your shots accordingly. Some people recommend timing the shot while the boiler is heating (how many seconds since the boiler power indicator light switches on.) Other methods recommend timing the shot as the boiler is cooling (how many seconds after the light switches off.) There are a number of different methods described on various websites; some are quite simple while others require specialized measurement devices and repeated scientific experimentation. How deeply involved you care to get is entirely up to you.
Over the years we’ve tested many ways to regulate temperature on the Silvia, and we have a simpler method. It may not be as precise as some of the 19 step processes you’ll find online, but for most people it will suffice to pull a sweet, rich shot.
In short, we recommend that you steam the milk first, then bleed off the excess pressure and steam out of the grouphead. If you leave the brew switch on for about 15-25 seconds, or until the steam dissipates and only water is coming out of the grouphead, there will be enough of a temperature drop in the boiler that the thermostat will force the boiler to start heating up again. Once the boiler has turned off, if you wait about 30 seconds, you’ll be pretty close to 200 degrees Fahrenheit and ready to pull a good shot. This process should take 2-3 minutes, which is just about the time you’ll need to grind and tamp in preparation for pulling a shot. Be sure to swirl and gently knock your pitcher of steamed milk to maintain consistent texture and “keep it alive.”
What is the difference between vibratory and rotary pumps?
Hook your espresso machine up to your kitchen plumbing and you’ll never have to worry about filling up your water tank! Direct connect kits usually attach to your cold water line going to your refrigerator. These kits are designed to be installed by the homeowner, without extra trips to Home Depot.
When direct plumbing, we recommend installing an inline softener and filtration kit. These can be purchased for around $110. Softened water will prevent mineral buildup from accumulating in your boiler, and the filter will ensure your espresso tastes like it should.
What are “no burn steam wands”?
The typical steam wand can get really hot to the touch and can burn milk residue, creating a buildup that must be cleaned off. Some of our machines offer “no burn wands,” which are steam and hot water wands that are double-insulated so they're cool to the touch, even while steaming or dispensing hot water.