I have been looking forward to writing this short series for quite some time. The purpose is to provide some insight into the very basics of coffee history and preparation. At Sunergos, it is easy to take for granted the joy that we have in our work. Learning daily is simply a part of the process of being a barista who is passionate about coffee as a craft. My goal here is to impart some of this knowledge that we use on a day-to-day basis and, hopefully, demystify the world of coffee a bit.
What I want to discuss here is Espresso (Ess-press-oh). To start, let’s discuss some common misconceptions. Espresso is not a particular type of coffee bean or a certain way of roasting coffee. Espresso is simply a way of brewing coffee. Most coffee drinkers can tell a difference between coffee brewed in a home drip machine versus something like a French press. In much the same way, espresso has distinct characteristics that separate it from other methods of brewing coffee. For reference, a working definition of espresso is: roughly 14-20 grams of coffee, ground fine, and brewed under 9bar (144 PSI) of pressure over a period of 20-30 seconds with a yield of about 2 ounces of concentrated coffee.
The beginning of our modern concept of espresso dates back to 1885. Angelo Moriondo created a machine that only somewhat resembled our current crop of espresso machines. It wasn’t until 1905 that Desiderio Pavoni (Founder of the company ‘La Pavoni’) began producing espresso machines commercially at a rate of 1 per day. In 1938 lever based machines were introduced, which eliminated the burnt taste that early espresso machines were notorious for due to the water used for brewing being too hot. These lever based espresso machines revolutionized the quality of espresso that could be produced, eventually leading to the pump-driven machines that are most common today.
A beautiful lever espresso machine.
So how is espresso actually made? It begins with the grind. Espresso grinders work very similarly to any coffee grinder, their job is to provide a consistent and even particle size. Where espresso grinders differ is in the range of settings and how those settings are used. In a standard grinder, the goal is to provide settings that range from a very coarse grind to a powder-fine grind. The steps between each setting are generally large to be capable of such a vast range. Espresso however is always ground fine, slightly finer than the consistency of sand. The goal is to have tiny adjustments to have a high level of control within this very-fine range.
After grinding, the coffee is poured into the Portafilter, the small, handled, brewing basket of an espresso machine. The coffee is then settled into the metal basket (which can be compared in some ways to a paper filter in other brewing methods). After settling, a device called a Tamper is used to apply pressure to the coffee in order to create a compressed puck. This compression is used so that there is resistance when water is passing through the coffee; this attributes to the heavy mouthfeel and intensity of flavor that espresso has.
An example of proper tamping and insertion of the portafilter.
When tamping is done, the portafilter is ready to be locked into the espresso machine. There is a rubber gasket that seals the rim of the metal basket to the Grouphead, which is the spout from which water pours. At this point, the barista activates the brew cycle which forces water at a pressure of 9 bar (about 144 PSI) through the compressed puck. Since the coffee is providing resistance, it takes around 20-30 seconds for 2 ounces of water to pass through. While the water is coming through the coffee it extracts oils, sugars, CO2, and lots of other solids within the coffee.
High caliber espresso requires great attention to detail; temperature, amount of coffee, consistency of tamping, and time of extraction all play an important role in the brewing process. If any of these factors are changed, the flavor, mouthfeel, sweetness, and balance are all affected. You will undoubtedly find a huge variety of opinions about proper temperatures and all of the other variables that go into espresso extraction.
An example of 2 opinions are the traditional, Italian methods of producing espresso versus what many American coffee shops are doing. A hypothetical Italian recipe for espresso could consist of: a dark roasted blend of several coffees, exactly 14 grams measured out into a basket, a very fine espresso grind with a light tamp, a temperature of 196F, and an extraction time of around 40 seconds. An American barista may use a recipe such as: a light roasted single origin espresso, 20 grams of coffee, a coarser espresso grind, a hard tamp (40lbs or so), a temperature of 203F, and an extraction time of 28 seconds. While both of these baristas are producing espresso, the resulting brews will be very different. The Italian espresso will likely have a smoky flavor (due to darker roasting), a light body (less total coffee used), and a great deal of balance (due to blending of coffees). In contrast, the American espresso will have a citric or bright flavor (due to lighter roasting), a heavy body (greater amount of coffee used), and more emphasis on the flavors to be found within the single coffee used (single origin as opposed to blend). This variety of opinion stems from the inherent subjectivity of tasting in general. Also, despite the knowledge had by coffee professionals and enthusiasts, there is much to still learn about espresso on a scientific level. As a whole, the coffee community at large is seeking to understand and experiment more and more with this elusive brewing method.
In the future we may discuss how each parameter affects flavor components directly and other more in-depth ideas. My parting request is that you would keep an open mind when it comes to espresso and coffee in general. There is plenty of room for preference and it really is all about what tastes good… which is of course completely subjective.