Espresso machines are really a breed of their own in the foodservice world. They involve a number of components and concepts that don't apply to any other type of equipment. It pays to know a few key terms before you set out shopping for a new machine.
- Portafilter is the basket that holds the coffee grounds. It also holds the spouts that the brew eventually flows through. The portafilter is attached to a handle, so it can be quickly cleaned and refilled for each shot of espresso.
- The grouphead is the receptacle to which the portafilter attaches. Pressurized water flows through the grouphead to get to the grounds.
- Tamping is the process of packing grounds into the portafilter. Getting the right density of grounds is essential for a well-balanced shot.
Level of Automation
The primary difference between espresso machine models is the level of automation that they provide to the brewing process. Some models put more control in the hands of the barista, while others automate nearly every step. There are three types to choose from, and each tier comes with a tradeoff between fine control over the end product and the complexity of training required to operate the machine.
Superautomatic machines automate nearly every step in the brewing process. These have built-in hoppers that hold beans, and they grind, tamp, brew, and dispense the espresso according to the settings the barista chooses. They even empty spent grounds into a receptacle that is easy to clean out. The only thing left to the operator is to press a button, collect the shot, and froth the milk when required.
Fully-automatic machines leave the grinding and tamping to the barista. Once the portafilter is inserted, the barista just selects the number of shots they need. The machine brews and dispenses the brew and the barista must empty the spent grounds afterwards.
With a semi-automatic machine, the barista must grind and tamp the beans, insert the portafilter, then start and stop the flow of water based on the number and intensity of shots desired. Because these are the least-automated of the types available, they require the most skill on the barista's part, as he or she must understand the relationship between time and the intensity of a shot, and learn to identify the quality of a shot by sight. The barista must also learn how to diagnose any problems when the shot doesn't come out as expected. Despite the extra effort required, this type is particularly popular in high-end coffee shops, where customers expect to see a skilled barista do the work.
Number of Brew Groups
The brew group is the collective term for the portafilter and grouphead assembly that ultimately produces the espresso. The number of brew groups on a given machine is essentially the same as number of drinks you can prepare at once. High-volume shops that have more than one barista behind the counter could benefit from two or more brew groups.
Espresso machines must maintain precise water temperatures to produce good-tasting shots, and that's where boiler size comes in. Boilers heat water and maintain it at the right temperature, so if you use the water faster than the machine can heat it, you'll either have to wait or you'll brew drinks that come out tasting bitter. A larger broiler can handle a higher volume of customers
Recovery rate describes how quickly the machine can get water back up to the correct temperature as the reservoir is emptied. The biggest factor in recovery time is the machine's wattage rating. The higher the wattage, the quicker the machine can heat water. Higher-voltage equipment will generally produce a higher wattage, so 220 V equipment can recover faster than 120 V machines.
There are no set-in-stone rules for matching these numbers with the expected customer volume, but just know that if you're concerned about your machine keeping up, it's a good idea to err on the size of choosing a machine that's too large so you can be sure to handle a rush of customers.