Distribution Tool vs Tamper: How to Use Correctly and Espresso Extraction Parameters Affecting Americano Taste Factors

Understanding Coffee Distribution Tools: A Professional Guide

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When making espresso, you'll notice that baristas frequently use two tools to work with the coffee grounds in the portafilter after receiving the freshly ground coffee: one is a flat cylindrical distribution tool, and the other is a tamper with a handle. Many friends watching FrontStreet Coffee's baristas make espresso have curiously asked about the purpose of these two tools. In this article, FrontStreet Coffee will introduce what distribution tools and tampers are.

First, let's briefly understand the steps of making espresso:

Clean portafilter → Grind coffee and dose → Distribute grounds → Tamp → Lock portafilter and extract espresso simultaneously → Extraction complete, clean portafilter. Distribution tools and tampers are auxiliary tools used during the distribution and tamping steps.

What is the Purpose of Coffee Distribution?

The primary goal of distribution is to ensure the coffee grounds in the portafilter are evenly distributed with a flat surface, allowing for uniform espresso extraction. When coffee is ground by the grinder and naturally falls into the portafilter, two problems typically occur: first, static electricity generated by the electric grinder causes coffee grounds to clump together; second, the overall density of the coffee grounds falling into the portafilter is uneven. There are usually two distribution methods: one using fingers for distribution, and the other using a distribution tool.

Is it Better to Use Fingers or a Distribution Tool for Coffee Distribution?

FrontStreet Coffee recommends using a distribution tool during the distribution process. First, using fingers for distribution gives an initial impression of poor hygiene. Second, it's difficult to achieve a truly uniform state when distributing coffee grounds with fingers, which increases the density between coffee particles and intensifies channeling effects. Once excessive channeling occurs during distribution, even perfectly even tamping force in the next step cannot remedy the situation. Additionally, using fingers to distribute coffee may not effectively break up clumps formed by static electricity from grinding, causing inconsistent density between coffee particles and affecting the final coffee extraction.

Advantages of Using Distribution Tools

Currently available distribution tools on the market include single-blade, three-blade, and four-blade types. FrontStreet Coffee uses a single-blade distribution tool. Without exception, all three shapes of distribution tools serve to achieve even distribution of coffee grounds in the portafilter. Most distribution tools are adjustable in height, where the height actually determines the degree of compression applied to the coffee grounds. FrontStreet Coffee recommends setting the distribution tool height to 1mm for double-shot portafilters and 2mm for single-shot portafilters. A distribution tool set too high will not only evenly spread the coffee grounds but also compress them during the process, which affects the tamping force needed in the next step and ultimately impacts water flow during extraction.

What is the Purpose of Tamping?

Tamping primarily prevents channeling effects and ensures more uniform coffee extraction. After distribution, gaps between coffee particles may still be uneven. Additionally, loose coffee layers are easily washed away by 9-bar hot water during extraction, creating more channeling effects. Compacting the coffee grounds makes them denser, minimizing gaps between coffee particles and reducing the likelihood of channeling.

How Much Pressure Should We Apply When Using a Tamper?

Tamping pressure varies from person to person. Around 2000, when La Marzocco was designing the Swift automatic filling device, they conducted extraction experiments with forces ranging from 2 to 30 pounds (approximately 15kg). They discovered that regardless of the applied force, the force was almost completely absorbed by the time it reached the bottom of the coffee puck. Therefore, tamping pressure has minimal impact on espresso extraction as long as the coffee grounds are compacted firmly. You can also "feel" the compression changes of the coffee puck while tamping—there's no need to press too tightly. If the coffee puck is compressed too tightly, its resistance becomes too strong, water takes longer to penetrate the puck, and the resulting extracted coffee becomes thick, bitter, and burnt-tasting.

What's the Difference Between Americano Made from Untamped, Evenly Tamped, and Over-Tamped Coffee Grounds?

In this experiment, FrontStreet Coffee used sun-processed Yirgacheffe blended with Sherry barrel-fermented coffee beans for espresso extraction. Extraction parameters: 19g coffee dose, 35ml extracted espresso liquid, extraction times of 22s, 27s, and 32s. Then, by adding 180ml of hot water, three different Americanos were made for comparison.

The Americano made from untamped coffee grounds had sharp acidity, thin taste, and no body whatsoever.

The Americano made from evenly tamped coffee grounds had rich whiskey aroma, gentle fruit acidity, and nutty aftertaste.

The Americano made from over-tamped coffee grounds showed burnt characteristics, was bitter upon entry, and difficult to swallow.

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