The Golden Rule
Extracting espresso is a skill that requires practice and an awareness of the factors that will impact the quality of the shots you pull. The following guidelines, deemed by many to be the "Golden Rules" of espresso extraction will provide you with a solid foundation upon which to build your knowledge of espresso crafting.
Single Shot: 1-1.5 fluid ounces of water, pulled through approximately 7 grams of ground coffee in 20-25 seconds.
Double Shot: 2-2.5 fluid ounces of water, pulled through approximately 14 grams of ground coffee in 20-25 seconds.
Dosing Your Coffee
Based on the type of filter basket you are using (a single or a double shot) the amount of ground coffee used will vary. For a single shot, 7-9 grams of ground coffee should be used. For a double shot, 14-16 grams of ground coffee should be used. Please note that Gaggia commercial-style filter baskets are traditional double-shot filter baskets that hold between 14-16 grams of ground coffee.
Tamping is the process of applying pressure to your ground coffee to compact it into an even puck. Tamping is an important step in the extraction process, as it impacts the rate at which water flows through the grounds. A tamping pressure of approximately 30 lbs is ideal for extracting consistent, flavorful shots of espresso.
Alongside tamping, the fineness or coarseness of your grind is an important factor in determining the flow rate of water through the grinds. Unlike tamping pressure, which can be maintained at a constant 30 lbs, the fineness of your grind will need to be adjusted as your coffee ages. As the coffee gets older and dries out, it will need to be ground more finely in order to extract the same kinds of ideal, crema-rich shots. As a rule, the finer the coffee is ground, the slower the rate of flow will be.
As indicated above, the total time required to extract a single or double shot of espresso should be approximately 25 seconds. By timing your shots, you can observe whether your shot is flowing too fast or too slow, and adjust other variables accordingly.
When you purchase a Gaggia semi-automatic espresso machine, you can do so with the confidence that you are equipping yourself with the tools to brew consistent, flavorful espresso. For your convenience, each of these machines comes standard with three types of filter baskets, the pressurized single-shot, pressurized double-shot, and commercial-style filter baskets.
For entry level users, the pressurized filter baskets provide a simplified approach to brewing espresso. Pressurized filter baskets eliminate the need to tamp; simply fill the basket with ground coffee (7 to 9 grams for a single-shot and 14 to 16 grams for a double shot) and lock it into the brew group. These types of baskets allow for the use of most types of pre-ground coffee, eliminating the need to own a grinder.
Pressurized ESE Pod Basket
The pressurized single-shot basket is compatible with ESE (Easy Serve Espresso) pods, further simplifying the brewing process and eliminating mess.
Two-Way Pin Insertion into Pressurized Basket
PLEASE NOTE: To use pressurized filter baskets, the black two-way pin included with the machine must be inserted in the portafilter prior to inserting the filter basket.
Commercial Style Filter Basket
The commercial style filter basket is a traditional double-shot basket ideal for those who prefer a finer degree of control over the brewing process. Fill the basket with 14 to 16 grams of coffee and apply approximately 30 pounds of pressure to the grounds with your tamper. Factors such as tamp pressure and grind fineness play a much larger role when brewing espresso with the commercial style basket.
The extraction of espresso from ground coffee is a markedly different process from brewing drip coffee. Espresso is created when hot water is forced through finely ground coffee at very high pressure. What follows is an explanation of the different types of machines available, and how they achieve this
Manual espresso machines are the most basic when it comes to espresso extraction. Water is heated inside the machine's boiler, while the pressure needed to extract the espresso is generated by manual levers that are pulled by the operator. (This is how the term "pulling a shot" originated.) Manual style machines make use of portafilters and require the coffee to be ground and tamped prior to brewing.
Semi-automatic espresso machines are a bit more sophisticated than manual machines. In addition to possessing a boiler to heat water for espresso extraction, semi-automatic machines generate the desired 9 bars of pressure via the use of an electric pump. Semi-Automatic machines can feature levers, rocker switches, or push buttons to operate the pump. Like manual espresso machines, semi-automatic machines also make use of portafilters and require the coffee to be ground and tamped prior to brewing.
Super-automatic espresso machines incorporate more technology in their design than manual or semi-automatic machines and are designed to simplify the user experience. In addition to utilizing boilers and pumps to produce heat and pressure, super-automatic machines also possess internal grinders and tamp coffee through the use of a mechanism known as the brew group, where the grounds are compacted into a puck similar to that created in a portafilter.
WHAT IS CREMA?
One of the aspects that defined the coffee produced by Achille Gaggia's patented espresso machine design in 1938 was the thick crema produced by the pressure-brewing process. Rich crema has since become a highly desirable feature for modern espresso drinkers, but what exactly is crema? In truth, crema is a foam, created by suspended solids and CO2 – a phenomenon that only occurs in espresso, which was originally dubbed caffé crema (cream coffee).
Unlike brewing drip coffee, where gravity pulls hot water through ground coffee at regular atmospheric pressure, espresso is ideally brewed at 9 bars of pressure, the key factor which allows for crema to be produced. The high-pressure environment inside the portafilter allows for the water to become supersaturated with CO2. When the water exits the portafilter in the form of espresso, the CO2 forms into thousands of tiny bubbles which are coated by parts of the oil extracted from the coffee, thus becoming the foam the floats on top of your espresso, aka, the crema.
Without question, the temperature of your espresso can make or break your experience. Even with perfect preparation, shots that lack temperature stability will cool too quickly, producing an espresso that leaves something to be desired. Conversely, there are circumstances, such as switching from steaming to brewing, where the water in your brewing process will be too hot. Fortunately, ensuring temperature stability is easier than you might think. Outlined below are several methods you can employ to ensure that your coffee is brewed at the correct temperature and stays at the correct temperature.
PREVENT HEAT LOSS
Preheat Your Portafilter: If you're just turning your machine on, the heat from the boiler may not have had enough time to properly heat your portafilter. Before brewing, it is always a good idea to pull a blank shot to heat up the internals of the machine as well as your portafilter. A blank shot is performed simply by pulling water through the machine as if you were brewing espresso. Additionally, if you're going to be brewing multiple shots, try to keep the portafilter locked into the group head to prevent heat loss between extractions.
Preheat Your Cup: Your espresso cup is your coffee's final destination and the last opportunity for it to lose a significant amount of heat. By preheating your cup, you help to ensure that the temperature of the coffee does not drop when it enters the cup. An easy way to preheat your cups is to fill them with hot water from the steam arm or group head. Alternatively, you can use your machine's cup warmer if it has one, although this will take longer.
The Cooling Flush: In certain circumstances, such as when you use the steam wand to prepare multiple specialty drinks, it is important to make sure that your water isn't too hot to be used to brew espresso. In single boiler machines, like the Gaggia Classic, which has only one boiler that heats water for both brewing and steaming, performing a cooling flush can prevent you from burning your espresso.
When you use your machine to produce steam, the water is heated to a much higher temperature than is appropriate for brewing. If you immediately go from steaming milk to brewing espresso, the water in the boiler is likely to be much hotter than it normally would be. A cooling flush involves running water through the steam arm and through the group head after steaming. Not only will you clear out any residual milk from the steam wand this way, you will also drain the hotter water from the boiler, preventing you from brewing shots that are too hot.
For some people, the tamper is just one of the many tools involved in the preparation of espresso, whereas others view it is an intimate and integral step in the process. As you embark on your journey to personalize and perfect your espresso experience, the type of tamper you use may one day become an important factor in how you prepare your espresso. Over the years a number of variations on tamper designs have emerged, but we'll confine our discussion to two key varieties.
The first tamper we'll discuss is the traditional flat tamper. Flat tampers, as their name implies, have a flat surface, which you use to compact and level your coffee. Flat tampers provide an even surface for the water to flow through, which some view as being ideal for espresso extraction.
Convex tampers are designed with a slightly rounded surface. They are preferred by some, as it is believed that they are better at compacting the coffee on the sides of the filter basket. Because the center of the tamper is slightly deeper than the edges, some believe this causes water to flow better through the center of the puck during extraction.
When using a traditional, commercial style portafilter, tamping your coffee becomes an important variable in the preparation of your espresso. As recommended by the "Golden Rules," a tamp pressure of 30 lbs is desirable when trying to achieve consistent, quality shots. Maintaining a consistent and specific tamping pressure of 30 lbs eliminates an entire variable from the brewing process, allowing your to modify other factors such as grind fineness and observe the differences in the shots you pull.
While it is true that the extraction time of your shots is largely determined by your tamping pressure and the fineness of your grind, grind fineness is more difficult to measure, and as a result, more difficult to duplicate. Additionally, regardless of the fineness of your grind, tamping too lightly or too strongly can still result in shots that are too fast or too slow respectively.
So, how do you achieve consistent tamping pressure? Well, the real answer is practice. Like all elements of brewing espresso, tamping is a process that requires a bit of time to master. An easy way to get an idea of what 30 lbs of pressure feels like is to place a towel on a bathroom scale and press down, you'll be able to see just how hard you've been tamping. Alternatively, specially calibrated tampers and tamping mats exist that alert the user when 30 lbs of pressure has been achieved.