What Causes Espresso Machine Leaks? Why Do Coffee Machines Drip During Espresso Extraction?

Recently, many friends have provided feedback on FrontStreet Coffee's backend: "The coffee machine often leaks during the espresso extraction process."

This phenomenon is actually quite easy to resolve once we understand the principle behind it. Normally, during espresso extraction, water is contained within a sealed space and is only forced downward by the pressure applied by the coffee machine. However, if gaps appear in this space and it's not properly sealed, water will seep out through these gaps, creating bypass water. If your coffee machine frequently experiences leakage, FrontStreet Coffee strongly recommends paying attention to this issue. Not only can leakage cause bypass water to fall into your cup, affecting the extraction judgment and diluting the concentration of the espresso, but it can also prevent the coffee machine from building full pressure. With excessive or numerous gaps, pressure cannot build up properly, making it difficult to extract a delicious espresso.

FrontStreet Coffee's coffee machines also encounter this issue periodically, as it's somewhat unavoidable. But don't worry - it's not a major problem, and as long as it's not a machine malfunction, repairs aren't difficult. Today, FrontStreet Coffee will share why coffee machines leak during extraction and how to resolve this leakage problem.

1. Gasket Aging

Essentially, when a coffee machine experiences frequent leakage, there's over a 90% probability that it stems from "gasket aging." Behind the dispersion screen in the coffee machine's brew head lies a gasket. The gasket serves two purposes: one is to secure the dispersion screen, and the other is to create a seal, ensuring the portafilter remains sealed during extraction.

Due to the material composition of gaskets and daily wear and tear, their deterioration rate is much faster than other components. The typical lifespan of a gasket is about one year, after which most coffee machines will begin to show leakage. When you notice that locking the portafilter handle becomes easier, and when the locked position deviates significantly from its original position, if leakage occurs simultaneously, there's no doubt that it's caused by gasket aging (most likely). Once we've determined the problem originates from gasket aging, we can proceed with replacing the gasket. Replacing the gasket isn't difficult, but since other situations can also cause leakage, FrontStreet Coffee will explain gasket replacement at the end. Everyone can first check if other possible causes exist before deciding whether to replace the gasket.

2. Portafilter Not Properly Locked

This is the second most common issue after gasket aging - the portafilter not being properly locked. Many friends, concerned about reducing wear, don't apply enough force when locking the portafilter. Because it's not locked tightly enough, the portafilter basket doesn't reach the designated position to create an effective seal, allowing water numerous gaps to seep through.

This situation is quite easy to determine with two indicators: first, assess whether you're applying sufficient force when locking the portafilter; second, observe whether pressure increases during extraction. Generally, if the portafilter isn't properly locked, the coffee machine will struggle to build pressure. We can use these two points combined to determine if the coffee machine leakage is caused by an improperly locked portafilter. Of course, the most direct testing method is to simply make another cup of coffee , remembering to apply force when locking it.

3. Excess Debris on Portafilter Basket

This is a popular explanation online, suggesting that coffee powder covering the entire exterior of the portafilter basket prevents proper sealing when the portafilter is locked, thus causing leakage. In reality, leakage caused by excessive debris is quite rare! The reason is simple - for this to occur, the portafilter would first need to be extremely dirty, with coffee powder covering the entire perimeter of the basket. This is nearly impossible unless the coffee machine's brew head hasn't been cleaned for an extended period. In most cases, the first two causes are more prevalent.

Besides these three points, other factors like incompatible portafilters or overfilled coffee grounds can also cause leakage. These situations are similar to the second point - their causes are quite easy to identify, so FrontStreet Coffee won't elaborate further. Now, let's have FrontStreet Coffee share how to properly replace a coffee machine gasket!

How to Replace a Coffee Machine Gasket?

It's quite simple. We just need to find and purchase the same model gasket from online stores or the coffee machine's official website, then follow the video instructions provided by the seller to remove the old gasket and install the new one. Because different coffee machines have varying structures, the replacement method may differ. FrontStreet Coffee will use the Lelit3 as an example, which represents how most coffee machines have their gaskets replaced. First, we need a sturdy prying tool - a screwdriver will also work. Then, position yourself to locate the gasket in the coffee machine's brew head, aim the prying tool at the gasket or the dispersion screen casing beneath it, and apply force to pry it out.

Yes, it's really that straightforward! After prying it out, we install the new gasket and reattach it to the brew head. Although it looks simple, it truly isn't difficult. Of course, during this process, we can also clean the dispersion screen appropriately to ensure the "health and wellness" of our coffee machine.

- END -

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473