Home Equipment
Determining your needs
Home espresso machines are available in a complex array of styles, features, price and technical complexity. Before you spend money on a machine, it is important to determine your needs. The first thing is to determine what you like most about the espresso experience. If you like the frothy feel of cappuccinos, flavoured and steamed milk in lattes, the chocolate in Mokas - with the actual flavour of espresso being of secondary importance - then a less expensive machine may be fine.
On the other hand, if the quality, flavour and ritual of making your espresso are paramount to you, then a high quality semiautomatic, pump machine may be your best choice. A super automatic - for reasons described below - may not be the best choice if you are a straight espresso drinker. Another important question is: How often will you use the machine? Daily use demands a higher quality machine, preferably with a 3-way solenoid electro valve. If you use the machine for say, weekend use and the occasional dinner party, a less expensive machine will fill the bill nicely.
Coffee Machines
Moka - usually eight faceted sides, roughly hourglass in shape, designed to make low-pressure espresso (2 bar) on a stovetop. Technically its not espresso because of the low pressure, but they still have a loyal following and are fun on a camping trip.
Moka is a generic name given to these eight sided, hourglass shaped 'mini percolators'. There is an upper and lower compartment that screw together with a strainer type coffee basket in the middle to hold a certain amount of coffee depending on the model (1-cup, 4-cup etc.) It is important to fill the coffee compartment completely with finely ground coffee and for this reason you may end up using more coffee than intended if you have a larger model. Add water to the lower compartment and apply heat. Water will rise through the coffee grounds and into the top compartment. Remove from heat and pour into your demitasse. Problems include the water boiling which will create a bitter cup, the low pressure is not a true espresso and there is no way to froth milk without a separate steam unit.
Stovetop espresso - similar to Moka in operation and size, but can develop slightly higher pressure, often with an attached steam wand; can be tricky and finicky to operate - unless you are a devotee they are best left on the shelf.
The Stovetop is similar to the Moka but with a valve on the side or top to control and dispense the brewed espresso. With skill, the pressure can be raised and the flow controlled, but they still must have the coffee compartment full to work properly. Tamp and grind can be an issue; too fine a grind coffee and too hard a tamp, and you will inadvertently discover how the pressure safety valve works! After brewing the espresso and raising the heat slightly, steam for foam can be produced through the steam wand, but the steam can diminish quickly once removed from the heat source.
Steam - fill a boiler, screw the cap down and wait for one or possibly two shots of near espresso (4 - 6 bar) to be produced; unit must cool down before refilling, a fussy entry level machine that will be quickly outgrown by most.
The electric Steam espresso machine still does not produce a true 8 bar espresso, since they operate at around 4 - 6 bar. These are the famous $49 to $99 dollar specials from the department stores. They can be quickly identified by the large round, screw top on top of the machine, which is used to fill the boiler. These are entry-level machines and once people discover true espresso, they put these in the yard/garage sale.
Piston espresso machines - uses a piston which is forced by a hand-operated lever to force water through the coffee grounds, the tall boiler doubles as the water reservoir.
These downsized versions of their commercial brothers are romantic favourites for coffee enthusiasts and 'purists' alike. If you enjoy a little extra work and the ritual of making espresso by hand, these machines are fine. They tend to be expensive, warm up time is slow (because the amount of water in the combined boiler/ reservoir is larger), and since they often have an all brass or chrome finish, tarnish and fingerprints are common. But they look superb on the counter and can produce an excellent espresso for those who enjoy the ritual! If the machine has a single heating element it may not produce as powerful a steam as those with a dual element system will. Consistency of the pull on the lever is important to obtaining a good extraction. A boiler pressure gauge if available, is helpful while learning.
Semiautomatic Pump machines - the vast majority of machines fall into this category, portafilter handle, single and double baskets, switches to brew espresso, make steam and hot water, some machines with an integral grinder.
The most popular type of machine for the home, the semiautomatic is an excellent choice for the majority of users. These all have a water reservoir (some can be plumbed in), vibration pump, boiler (or thermoblock), and group head with a removable portafilter (handle assembly). All have a device for steaming milk. The user fills the coffee basket with properly ground espresso, tamps it (applies pressure), inserts the portafilter handle and presses the brew switch to start the extraction process. In 25 to 35 seconds the switch is turned off. Depending on whether the single or double basket was chosen, a single 25mls or double shot 50mls of espresso can be produced.
Automatic espresso machines - very few machines, same features as semiautomatic machines, except that the shot size(s) can be pre-programmed; sounds great but not really a feature worth the extra cost and complexity.
The home automatic espresso machine has all the features of the Semiautomatic plus the ability to deliver a pre-programmed single and double shot (in effect turning the pump off by itself). There are a few automatic home machines on the market.
Super automatic espresso machines - (push one button to start a full cycle - grind and tamp the coffee, brew it and eject the grounds into the storage hopper; some have cleaning, decalcification or auto-rinse cycles.
Superautomatic is the name given to those machines that - with the press of a button - grind the coffee, move it into the brewing chamber, pack it, brew the espresso shot and then eject the grounds into a built-in dump box. These espresso machines are more expensive, but of course are nearly operator foolproof. While they may seem to be the obvious answer, they have minor drawbacks, which must be considered. Generally speaking, superautomatics give you more consistency, but may have a much lower overall espresso quality. They are more complicated internally, and may require a little more maintenance and service down the road. If you tend to overlook these things it is a good idea to get a machine that has cleaning cycle and decalcification cycle reminders and self-diagnostics. Although many machines look similar in size on the outside, there is a wide range of performance and features.One major difference is whether the machine has a single or double boiler system (or thermablock). Some home units have a single boiler or thermablock assembly and just like the semi-automatic machines need an extra 45 seconds or so to heat up to steam temperature and another three or four minutes to cool back down before coffee making . This mandatory cool-down period can be an inconvenience if you are having a dinner party and need to make multiple drinks. Single-boiler machines will not allow coffee making until the "overheat/not ready" message or light "disappears". As stated previously, superautomatics, by virtue of their design, have to deliver their boiler/thermoblock water a short distance through unheated parts. For this reason, straight short espresso shots tend to be a few degrees cooler than those made on traditional machines.
Understanding the components
Water Reservoir: Since water goes "flat" in just a few days, it's an advantage to have a smaller tank that is filled more often. Fresh, oxygenated water makes good espresso. If you use your machine only occasionally, consider changing the water before you start and then run a half cup through the boiler to freshen it up.
Pump: Home espresso machines use a vibrating piston pump to force water into the boiler and then through the coffee grounds under pressure. The actual pressure that the pump develops is important: 8.9 - 9 bars is ideal. A too high pump pressure requires a finer grind of coffee to slow down the extraction process and there is a greater danger of over extraction.
Boiler Design/Heating Element: The material that the boiler is made of is less important than its 'mass' (weight and thickness) and design. The critical importance of proper temperature on good espresso extraction is one of the major failing in many cheaper and less well constructed machines on the market. A boiler made from thin stainless steel will fluctuate much more in temperature as the element cycles on and off, than the heavy marine grade brass boiler. Also, in a system where two elements are embedded on each side of the thick exterior of the boiler they do not touch the water and this dual element system improves the stability of the boiler water temperature. Both systems have been in use for 20 years without design changes and are solid in their durability and performance. By contrast, a microprocessor can be used to control the boiler heat instead of the more common button thermostat, claiming only a 2 degree F variation with this technology, which is also very respectable.
Boiler/Thermoblock: A boiler is nearly always used in home espresso machines to brew the espresso. Ninety percent of them use this same boiler to produce the steam for frothing milk (called a single boiler system). This is accomplished by raising the temperature (and pressure) in the boiler when you press the steam button; it usually takes about 45 - 75 seconds to build up pressure. Some makers (especially on the automatic and super automatic machines) build in a separate boiler/thermo block system for the steam function. The water in the boiler stays at a constant temperature for espresso and steam is created quickly by the thermoblock, that are capable of steaming continuously making them ideal for big jobs. There are also some home espresso machines available in the market that just have one thermo block - no boiler and the thermo block is used for the espresso and the steam.
Portafilter Handles: The portafilter handle, filter handle or group handle is ideally made of forged brass to give it durability. Aluminium construction on less expensive machines often fail over time. A heavy grouphandle also retains more heat, this helps maintain the finished temperature of espresso and the delicate flavour and crema as the espresso flows into the cup. Companies that make commercial machines use these very same portafilters in their home machines, which is definitely the best option. The filter baskets used in these commercial handles are capable of holding at least 12 grams and 20 grams of coffee (single & double respectively).
Coffee Valve/ 3-Way Electrovalve: There are two main methods for 'holding' the water in the boiler until the pump is turned on to brew espresso. The simplest method is a spring valve, often called a coffee valve. For light duty home service, these are acceptable. They do tend to drip over time and then need to be replaced. While a small cost, the problem is that on many machines they are an integral part of the boiler and can be difficult to repair if the boiler seal is pitted. Some machines use a coffee valve as a unique system that can be replaced as a unit, saving time and money. A superior method for heavier duty use is the 3-way backpressure relief solenoid valve (also called a drip free system). These are exactly the same valves that are used on commercial machines, and with simple maintenance such as backflushing, should last a lifetime in home use.
Steaming: The Steam switch is used to raise the temperature of the boiler enough to produce steam. This usually takes about 30 to 45 seconds. On machines with larger boilers, it will be the longer since there is more water to heat; the advantage is more steaming power. Machines that use a thermoblock system can often take much longer to build up a 'head of steam'. Machines with frothing adapters (turbo frothers, pannerello frothers, cappucciatore systems) simplify the aeration process, (no skill required) however machines with regular steam wands are easy to master once you know the correct technique, which is not hard.
Hot Water: Pump espresso machines can also deliver modest amounts of hot water for making café menu items like the Long Black. Some machines have a specific hot water switch which turns on the pump. By then turning on the steam valve, near boiling water is delivered out of the wand instead of steam. Machines that do not have this feature can also deliver hot water simply by leaving the portafilter handle with used coffee puck still in and turning the coffee switch on while opening the steam valve - hot water will now come out the steam valve.
Thermostats: Most single boiler home espresso machines have both a coffee and a steam temperature thermostat. For overheat protection many machines use a thermal fuse, which must be replaced by a service technician in the rare event that it is 'tripped'. Other machines use a resettable safety thermostat, which like a circuit breaker can be reset by the handy homeowner. Very high-end home machines using the heat exchanger system use an adjustable pressurestat, which besides being extremely reliable allow for infinite pressure and temperature adjustment. The overpressure safety system on these machines is usually a spring type safety valve.
Espresso Grinders: The correct grind is essential for a fresh, flavourful espresso. Fresh properly ground coffee is one of the secrets of making great espresso. A quality espresso grinder is an excellent investment. Achieving the fine, consistent grind required involves a solid, quality machine using burr or conical grinding disks that produce the correct grind, without heating and destroying the flavour in the bean. The burrs or cones must be of tempered steel to stay sharp and the motor should be hefty. Weight is a good indicator of motor strength and overall construction. The bigger and stronger the motor the lower the speed it is able to operate at, providing a better grind, and quieter operation. Espresso grinders that use conical cutters provide superior results as do burr grinders with 50mm diameter and larger burrs. A doser is provided on many grinders, which allows for the dispensing of a 'pre-measured' (dose) of coffee into the portafilter, improving the consistency. Doserless models are excellent for people who want to grind fresh since no grinds are left in the dosing chamber. Low cost blade grinders cannot provide the consistent grind required for good espresso. Other light duty home coffee grinders, with small diameter burrs while producing a passable espresso grind, will dull very quickly and frustrate the user.