Screens, gaskets, and baskets are the unsung heroes of the espresso machine. While their main job is to keep your equipment clean and running smoothly for many years, they’re also integral to pulling top-notch espresso shots. With precise geometry and hundreds of hours of design and quality control testing, these three parts are specifically built to help you extract the best-tasting espresso possible. They’re also designed to take most of the wear and tear of each shot pulled, meaning it’s important both for the health of your machine and the quality of your espresso to replace them when they start to wear out.
Screens
La Marzocco group head screens have undergone a number of subtle changes over the years, but the core design remains the same. The screens feature a fine mesh layer backed by a piece of stainless steel with a pattern of holes cut out and a ring of thick stainless steel wrapped around the edge to bind the two layers together. The hole in the center allows for the dispersion screw to fasten the screen directly to the group head, creating a barrier to prevent any ground coffee from entering the machine. But the design of the screen goes even further.
As water leaves the jet inside the group head, it travels through the dispersion screw, and it is shot in four directions toward the edge of the screen. The water then covers the entire inside of the screen and exits the screen through the holes cut in the stainless steel layer and comes through the fine mesh screen later in a perfect shower. This shower ensures water is evenly dispersed through the espresso puck during brewing, which extracts each shot evenly. Without the consistent water dispersion of this group head screen, espresso shots are far more likely to channel, leading to bitter and sour-tasting shots.
Gaskets
The group head gasket plays a more subtle role in espresso quality but an important one all the same. The gasket exists to form a seal between the espresso machine and the portafilter basket so that when the machine pressurizes, all the water moves consistently through the espresso puck at the exact same pressure. Ill-fitting gaskets or worn-down gaskets can often lead to inconsistent pressure and leaking, which is why La Marzocco switched from rubber to the much more flexible and durable silicone group head gasket. These silicone gaskets require less physical effort to create a seal with the portafilter basket, ensuring a much more consistent espresso-pulling experience than a traditional rubber gasket.
Baskets
The real star of any quality espresso is the espresso filter basket that the shot was prepared with. Like the group head screen, the primary purpose of a filter basket is to keep coffee grounds out of your cup. But a well-designed filter basket does so much more than that. Each La Marzocco filter basket is precision-engineered to ensure that the size of the holes and the number of holes at the bottom of the basket create the proper amount of exit surface area so that the grinder can be calibrated to the right grind size for each basket set dose. That means that a 17g La Marzocco is designed so that 17 to 18 grams of coffee fit to the ridge inside each basket once tamped. That amount of coffee creates a consistent bed depth, which is then calibrated to the total exit space at the bottom of the basket for an idea flow restriction so that the barista can properly dial in the espresso grinder to a 25 to 30-second shot time based on the proper grind size needed to extract the best flavors from the coffee.
If that sounds a bit confusing, well, it can be. Espresso filter baskets are built around complex formulas to maximize espresso quality based on bed depth, flow restriction, and overall shape and size. Ultimately, as a barista, having an incredibly well-designed basket means you can focus on the fundamental espresso variables and not have to worry about the equipment itself.
With that in mind, the more use each of these three parts gets, the more likely they’ll need to be replaced. You can set up a regular preventative maintenance cycle with your local service tech, or you can stock up on all three as spare parts and replace them as needed throughout the year. Just remember, not only do fresh screens, gaskets, and baskets keep your machine clean, they are also responsible for pulling the best-tasting shots.
