Those who are in the market for the perfect espresso machine obviously want to do their homework prior to making a purchase. With many varieties and price ranges, it is necessary to get a grasp of what is needed and how those needs will be best filled. Understanding a little about how machines are made will help give an idea of what will work best for any given situation.
Automatic/Semi-Automatic or Super-Automatic
As making espresso requires several steps, various machines are categorized by whether they will do some or all of the steps on their own. An automatic or semi-automatic machine will do the brewing, but require the operator to grind the beans, fill the portafilter, tamp the grounds, start and stop the brew, and empty the used grounds. An automatic machine has a pre-set amount of water, while a semi-automatic requires the operator to manually turn the pump on and off.
A super-automatic machine, however, takes care of basically all of the steps. Grinding, tamping, brewing, frothing, and even disposing of the used grounds is done automatically in many machines. The operator simply needs to fill water and coffee beans periodically, and choose whatever settings are preferred. While a novice operator will likely enjoy the convenience of this super-automation, hard-core coffee lovers–who believe in coffee as an expression of art–will want the ability to adjust many of these steps to their liking.
Boilers and Heat Exchangers
Brewing espresso and steaming milk happens at two different temperatures. When there is only one heating element, such as a single boiler, there is some lag time between pulling shots and steaming milk. Double boilers, which contain double the mechanism and are often double the price, are able to pull shots and steam milk at the same time. A nice cross between the two is a heat exchanger (HX) which has a single boiler but regulates the water temperature with a copper tube, but some of these models do require a cooling flush to keep them from becoming too hot. Thermoblock is one other viable option, if it is combined with a boiler (steer clear of cheap Thermoblock only models). These may allow for more steam than a single boiler and it is a slightly less expensive option than a heat exchanger.
Another part of the machine to understand prior to purchasing is the quality of the machine. Instead of thinking of an espresso machine as a small kitchen appliance such as a toaster, think more along the lines of a larger appliance such as a stove or refrigerator. Durability is key. Purchasing a plastic-y machine for around $100 is possible, but it is almost always regrettable. Instead, think of the lifetime of benefits that come from having a quality appliance which can last for ten years or more if well taken care of. Quality machines will be made with high-grade stainless steel which is durable and easier to keep clean than lower quality metals. The working parts, in particular, need to be the most durable and well maintained.
Now that you know many of the basic things you need to know about choosing an espresso machine, take some time to consider your needs, your budget, and your preferences. Comparing and contrasting various machines will give you a great idea of exactly what kind of machine will create the best espresso drinks for you.