Channeling: The Effect and How To Avoid It

Did you prepare your cup of coffee in the usual way only to be shocked by the bad and unbalanced taste? If so, then you can blame channeling in the coffee puck; it's the first cause in such cases.

Channeling occurs when coffee grounds are added to the portafilter and pressed; you will notice them on the face of the puck, but after tampering, they may disappear. However, in fact, they are still available under the surface at the bottom of the puck. When hot water descends, it penetrates faster through these cracks without extracting any flavor, which makes the dose unbalanced.

Causes of Channeling:

The quality of the grind: One of the most important reasons for channeling is the quality of the grind, some grinders leave some lumps in the coffee filter, and when pressed, they do not merge with the rest of the ground coffee, so the coffee is not rich enough for the water to pass evenly, so you have to dismantle the lumps first before pressing To ensure the end result.

• The quality of the ground coffee: The beans may be old, meaning its been more than three months since the roasting date, as the quality of the coffee begins to decline after a month of roasting, as the internal oils begin to volatilize, and the beans dry out, and the quality of the grind is affected, as the ground coffee does not become wet enough to stick together after pressing, which increases the rate of channeling.
  
  
• The type of coffee: The coffee may be intended for drip coffee and not for espresso due to its distinctive hints, oil quality, and degree of moisture, so it is not suitable for pressing for an espresso machine.
  
  
• Uneven tampering: Pay attention to the angle and force of tampering the coffee. When you tilt the tamper, even slightly, it will create an uneven surface, leaving water more room on one side of the filter than on the other, and thus the extraction will be unbalanced. The same applies to not loosening clumps or distributing the coffee in the filter before pressing.
  
  
• Knocking the portafilter to get rid of excess coffee: Sometimes, some of the ground coffee collects on the walls of the portafilter, so the barista knocks the portafilter on the work surface to bring it down to the bottom of the portafilter, forgetting the impact of the knock on the coffee grounds, as it will create cracks around the edges of the puck and at the bottom, which will lead to a bad cup of coffee. So instead of knocking on the portafilter, we recommend using a 58.5mm tamper.
  
  
• Technical problems related to the espresso machine: Your machine may need regular maintenance if you suffer from problems such as low machine pressure, which gives the water enough time to search for cracks and pass through them, or the pressure is too high, which makes the water come out quickly and with great force that causes cracks. Water flow issues will also cause the same problems, so you should schedule a visit for a service technician to check all the internal parts of your machine.

There is no specific type of portafilter to avoid the formation of unpleasant cracks, but you can avoid them by following the tips mentioned above. Grind the coffee, break up the lumps, then distribute and press and start extracting to get a rich, balanced espresso shot.