Why Distribute and Tamp Coffee Before Extraction? How to Properly Distribute Coffee for Espresso?

Understanding the Importance of Proper Coffee Distribution

As is well known, in the espresso making process, there is a step called "distribution." Although its operation is quite simple, its importance cannot be underestimated. The purpose of distribution is to make the coffee grounds more evenly distributed in the portafilter basket, which can reduce the occurrence of channeling. Conversely, if channeling occurs during extraction, it's most likely because the coffee wasn't distributed properly.

Recently, many friends have given FrontStreet Coffee feedback on a particular problem: their coffee puck appears perfectly flat and looks very uniform, but channeling frequently occurs during extraction, with espresso spraying everywhere and creating quite a mess. In such cases, there's only one cause: the uneven distribution of coffee grounds that FrontStreet Coffee mentioned earlier. The reason the puck appears flat is simply because your tamping has compressed the grounds to the same height, but in reality, the coffee grounds within the puck are still unevenly distributed – some areas have more coffee, while others have less. This leads to denser areas where there's more coffee and looser areas where there's less, causing hot water to concentrate and flow through the looser areas during extraction, forming channels.

There are two reasons for this situation: one is an excessive amount of clumped coffee grounds (as FrontStreet Coffee mentioned the day before yesterday); the other is improper distribution movements that cause uneven coffee distribution. According to FrontStreet Coffee's observations, the latter is more often responsible for channeling because many people directly use the portafilter to catch the grounds. Before distribution, we need to pour the ground coffee into the portafilter basket. There are two ways to transfer coffee grounds into the basket: using a distribution tool or directly using the portafilter.

The pros and cons of both methods are quite obvious. The former allows coffee grounds to fall more evenly into the portafilter basket, but at the cost of adding an extra step, making the coffee preparation process take longer. The latter allows for faster collection of coffee grounds, but at the cost of the coffee concentrating in one area when collected, creating piles. Then everyone needs to level the coffee grounds by stirring with fingers or shaking the portafilter. However, as long as the leveling operation is improper, it will cause the coffee grounds to concentrate in the initial piling position. For example, if coffee initially piles in the middle, improper leveling will result in more coffee in the middle and less around the edges, which in turn leads to channeling. Don't worry, next FrontStreet Coffee will share how to properly level coffee grounds.

Proper Finger Distribution Technique

The finger leveling method can be said to be the most traditional distribution method. After pouring coffee grounds into the portafilter basket, we use our index finger or the webbing between thumb and index finger to push back and forth on the excess coffee grounds, allowing coffee in "high" areas to fall into gaps as much as possible – this is a simple form of coffee distribution. When leveling, we need to ensure that fingers only push the coffee forward without applying downward pressure. Because if fingers apply downward force, the coffee in that area will be compacted first, making it difficult to distribute coffee from that position to other places through shaking/tapping later. Another point to note here is – remember to wash your hands.

The Importance of Gentle Movement

After using fingers to create a simple distribution of coffee grounds, we need to redistribute the coffee through shaking or light tapping, and this is where many friends often make mistakes!

Many friends will grip the portafilter tightly at this point and then tap it quite forcefully. What happens as a result? The coffee grounds will concentrate in the direction you're tapping. Although this approach does make the coffee grounds appear flat quickly, this is only superficial! Because most of the coffee grounds are actually concentrated in the area you tapped, which will also lead to channeling! Therefore, when tapping the portafilter with your hand, we should try to pay attention to the force of gripping and tapping – try not to use too much force. This allows the coffee grounds to be distributed as evenly as possible through gentle shaking, and extraction quality can be improved as a result.

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