How do I stop my espresso from spraying everywhere?

If your espresso is spraying out of the portafilter like a fountain, you are witnessing a classic case of channeling. This happens when the water finds a path of least resistance through the coffee puck, usually due to clumps, uneven density, or a poorly leveled tamp. Instead of flowing through the entire bed of coffee, the water 'jets' through these weak spots, resulting in a shot that is both messy and poorly extracted.

To fix this, you must improve your puck preparation. Clumps in your ground coffee are the most common cause of channeling. Using a WDT tool—a small device with thin needles—to stir the grounds in the basket can break up these clumps and distribute the coffee evenly. After stirring, ensure the surface is perfectly level before you tamp. A level tamp is essential for forcing the water to flow through the entire puck uniformly.

If you are using a bottomless portafilter, you will see these sprays clearly. While it can be frustrating, this is actually a benefit; it provides immediate feedback on your preparation technique. If you see a spray, you know exactly where your distribution failed. If you are using a spouted portafilter, you might not see the spray, but you will likely taste the results: a shot that is thin, sour, and lacks the rich, syrupy body of a well-extracted espresso.

In practice, focus on consistency. Use a scale to dose your coffee, a distribution tool to ensure uniformity, and a level tamper to finish the job. If you continue to see spraying, check your grinder for clumping issues or consider if your beans are too fresh, as high levels of CO2 can also cause erratic flow. By refining your prep, you will eliminate the mess and significantly improve the quality of your shots.