Brewing Espresso at Home
Coffee is a beverage that invites, even demands, obsession, and, of all coffee acts, brewing espresso can be the most obsessive. Two or three more seconds of dribbling out of the brewer can dramatically alter the cup, and the finest espresso coffee in the world can be utterly ruined by one or two careless gestures. Every time I publish a review of espresso coffees I receive emails, not about the coffees, but about problems brewing them. Hence the following, a (despite its length) succinct guide to brewing espresso right at home. (Note that the following instructions elaborate and complement those provided by the manufacturer of your espresso brewer. Be certain you have read and understood the safeguards, cautions, and instructions that accompany your brewing device before supplementing them with the advice and encouragement given below.)
Espresso Brewing Devices. Espresso machines or brewing devices fall into four categories.
Stove-Top Devices, or Caffettiere. These little devices, typically shaped like an hour-glass, hold the ground coffee inside a little sleeve at the waist of the brewer and push the water through the coffee by means of the pressure of steam trapped inside the lower chamber. Usually they do not incorporate a valve or wand for heating and frothing milk. Used carefully they may produce a flavorful coffee, but they will not produce a classic shot of espresso.
Countertop Steam-Pressure Devices. These small countertop apparatus incorporate a valve and wand for frothing milk and hold the ground coffee in a café-style filter holder that clamps onto the outside of the brewer. Like stove-top devices, they generate the pressure needed to force hot brewing water through the compressed bed of ground coffee by means of pressure exerted by the build-up of steam inside a little boiler concealed inside the housing of the brewer. Any countertop espresso brewer that retails for under $100 most likely works in this fashion. Used correctly, these devices produce excellent espresso drinks with milk, but will not produce a classic, stand-alone shot of espresso.
Countertop Pump-Pressure Devices. These somewhat larger countertop apparatus use a small, vibrating pump to force hot brewing water through the compressed bed of coffee. They also incorporate a valve and wand for frothing milk and hold the ground coffee in a café-style filter holder that clamps onto the outside of the brewer. The more intense, controlled pressure of the pump means that these devices, used correctly, will produce a café-quality classic shot of espresso.
Countertop Piston-Pressure Devices. With these picturesque, shiny metal machines the user provides the brewing pressure by pushing down on a lever, forcing the hot brewing water through the compressed bed of coffee. They also incorporate a valve and wand for frothing milk and hold the ground coffee in a café-style filter holder that clamps onto the outside of the brewer. These devices, used correctly, also will produce a café-quality classic shot of espresso. The most commonly available models are manufactured by Pavoni.
Coffee and Roast. Classic espresso is brewed using a coffee roasted medium-dark to dark brown, but not black. This roast usually is called espresso or Italian in stores, but any coffee brought to a medium-dark to dark brown roast, no matter what it's called, will make a plausible espresso. Typically, however, blends designed especially for espresso blends make the best espresso beverages. They range from mild, sweet blends best for straight espresso, to dark, rich, pungent blends best for long milk drinks like caffe latte. Always use at least as much coffee as is recommended by the manufacturer of your machine. Never use less. The usual measure for commercial machines is about two level tablespoons per serving. If in doubt, use two level tablespoons of finely ground coffee for every serving of espresso. In order to achieve a flavorful cup, you may have to use more. I find that with many home pump and piston machines a single serving of brewed espresso with the proper richness only can be obtained by using the double filter basket rather than the single, and by loading it with a double dose of ground coffee.
Brewing Principles. There are two requirements for making good espresso. First, you must grind the coffee just fine enough, and tamp it down in the filter basket just firmly and uniformly enough, so that the barrier of ground coffee resists the pressure of the hot water sufficiently to produce a slow dribble of dark, rich liquid. Second, you need to stop the dribble at just the right moment, before the oils in the coffee are exhausted and the dark, rich dribble turns into a tasteless brown torrent.
Grind. The best grind for espresso is very fine and gritty, but not a dusty powder. If you look at the ground coffee from a foot away, you should barely be able to distinguish the particles. If you rub some between your fingers, it should feel gritty. If you have whole beans ground at a store, ask for a fine grind for an espresso machine. A fine, precise, uniform grind is particularly important for pump and piston machines, which demand an especially dense layer of coffee to resist their high brewing pressure.
Preheating Group, Filter Holder, and Cup. Servings of straight espresso are so small and delicate that everything immediately surrounding the brewing act must be warmed in advance to preserve heat in the freshly-pressed coffee. If you have a pump or piston machine and are making your first cup, be sure to preheat the group, filter, and filter holder by running a small amount of hot brewing water through them. The demitasse into which you press the coffee should also be warm. Use the cup warmer on your machine, the top of your machine as an improvised cup warmer, or run some steam from the frothing wand into the cup. Those who drink their espresso with frothed milk can afford some carelessness in this regard. The hot milk usually manages to compensate lukewarm coffee and a cool cup.
Filling and Tamping. Different types of brewing devices have somewhat differing requirements for this important operation.
Filling and Tamping for Brewers with External, Café-Style, Clamp-In Filter and Filter Holder. Fill the filter basket with coffee to the point indicated by the manufacturer, distributing it evenly in the filter basket. With machines that work by steam pressure alone use your fingertips to consistently but lightly press the coffee across its entire surface. Don't hammer on it. With pump and piston machines use the device called a tamper that was packaged with your machine, and exert strong pressure, decisively packing the coffee into the filter basket. As you tamp the coffee you might simultaneously twist the tamper, which polishes the surface of the coffee and assists in creating a uniform resistance to the brewing water. Never use less than the minimum volume of ground coffee recommended for the machine, even if you are brewing a single cup. If the coffee gushes out rather than dribbling, compensate by using a finer grind or by tamping the coffee more firmly. If it still gushes out, use a bit more coffee and, if you are grinding at home, increase the fineness of the grind. If the coffee oozes out rather than dribbling steadily, use a coarser grind or go easier on the tamping. With pump and piston machines the ideal 1-to-1 1/2-ounce serving of espresso should dribble out in about 15 to 25 seconds from the moment the first drop appears.
A Note on Self-Tamping Machines and Pods and Capsules. Some pump machines have a self-tamping feature. The shower head on the underside of the group automatically compresses the coffee as you clamp the filter holder into the machine. You still need to use the tamper to assure that the coffee is evenly distributed in the filter basket, however. Machines that brew with pre-packaged, single-serving espresso pods or capsules require no loading or tamping. The pods or capsules are simply inserted into the special filter holder. With these machines you still must time the brewing accurately, however, to avoid ruining the espresso by running too much water through the ground coffee.
Filling and Tamping for Stovetop Espresso Brewers that Hold the Ground Coffee in a Filter Basket inside the Brewer. Most stovetop espresso brewers contain the ground coffee in a largish sleeve inside the device, rather than in a café-style filter unit that clamps to the outside. When using these stovetop devices with interior filter baskets, do not tamp the coffee unless the instructions that come with your machine ask you to do so. Use the same fine grind as recommended above, use as much as the manufacturer's instructions recommend, distribute it evenly in the filter basket, and proceed. For stovetop machines with café-style filter holders that clamp to the outside of the machine, tamp lightly as described above.
Clamping the Filter Holder into the Group. Always wipe off any grains of coffee that may have clung to the edges of the filter holder. They may cause brewing water to leak around the edges of filter and dilute the coffee. Also make certain that the filter holder is firmly and evenly locked into the group. Until you get the knack of the clamping gesture, you may need to stoop over and peer under the group to make certain that the filter holder is evenly snugged in place.
The Act of Brewing. Timing is everything in espresso brewing. The richest and most flavorful coffee issues out at the very beginning. As brewing continues, the coffee becomes progressively thinner and more bitter. Consequently, collect only as much coffee as you will actually serve. If you are brewing one serving, cut off the flow of coffee after one serving has dribbled out, even if you have two servings' worth of ground coffee in the filter basket. If you are brewing two servings, cut off the flow after two. And no matter how many servings you are trying to make, never allow the coffee to bubble and gush into your serving carafe or cup. Such thin, over extracted coffee will taste so bad that it's better to start over than to insult your palate or guests by serving it. If you are using a pump or piston machine, each shot or serving of espresso should dribble out in about 15 to 20 seconds from the moment the first drop appears. However, gauge when to cut off the flow of coffee by sight, not by clock or timer. The fineness of the grind may vary, as will the pressure you apply when tamping. Consequently, the speed with which the hot water dribbles through the coffee will also vary from serving to serving. If in doubt, cut off the flow of coffee sooner rather than later. Better to experience a perfectly-flavored small drink than an obnoxiously bitter large one. As you gauge the flow of coffee keep in mind that it will continue to run into the cup or receptacle for a moment or two after you have turned off the pump or shut off the coffee valve. If you use a pump or piston machine, brewing into a jigger, or bartender's shot glass, is a simple way of making certain that you do not produce overlong, bitter-tasting shots when you are brewing for frothed milk drinks. For a classic 1 1/4-ounce serving, brew the shot, including crema, up to the line on the glass. If your brewer does not have a mechanism for cutting off the flow of the coffee, you will need to improvise. If the design of the machine permits, use two separate coffee-collecting receptacles, one to catch the first rich dribbles, which you will drink, and a second to catch the pale remainder, which you will throw away. Whatever you do, don't spoil the first bloom of coffee by mixing it with the pale, bitter dregs.
Knock-Out and Cleaning. Pump and piston machines can be recharged with further doses of coffee while the machines are still hot. To remove spent grounds from a hot filter, turn the filter holder upside down and rap it smartly against the side of a sturdy waste container or against the cross-piece of the waste drawer that may have come with your system. This can be one of those pleasantly nonchalant gestures that perfects itself with time and practice. Aficionados may wish to professionalize by purchasing a small knock-out box of the kind used in small cafés. Wipe any leftover grounds off the edge of the filter holder and fill with the next dose of ground coffee. If significant amounts of spent coffee stick inside the filter you may need to rinse it before refilling. A few machines may not incorporate a catch to retain the filter inside the filter holder. In this case you have no recourse but to dig the grounds out with a spoon. Regularly wipe off the gasket and showerhead on the underside of the group. Spent coffee grains tend to cling there. Less often, pop the filter basket out of the filter holder, and wash both parts. Finally, take note of the manufacturer's instructions for decalcification. If you live in an area with particularly hard water, I would recommend using bottled water, particularly if you own a pump machine. The workings of these machines are especially vulnerable to calcium build- up.