Femobook A68 & A5 Electric Grinder Review | Indonesia Barista Champion

The Art of Processing at Altieri, Panama

In specialty coffee, the journey from a ripe coffee cherry to the brewed cup involves a series of biological and chemical transformations. In her talk, Indonesian barista champion Yessylia highlights coffee processing as a key factor shaping flavor development.

Using Panama Geisha from the Altieri estate as an example, she explains how different processing methods influence the final cup profile and how brewers can adjust their brewing strategies accordingly.

Comparing the Fundamentals: Washed vs. Natural Processing

Yessylia compares two processing approaches: the traditional washed method and a natural process known as River Flow fermentation.

Even when two coffees come from the same producer and variety, differences in processing can create noticeable changes in flavor, body, and extraction behavior. For brewers, recognizing these differences helps determine the appropriate grind size, water temperature, and pouring structure.

The Logic of River Flow Fermentation

The River Flow method used at Altieri is an experimental variation within natural processing.

Freshly harvested coffee cherries are first sealed inside airtight or low-oxygen bags, creating an anaerobic fermentation environment. These sealed bags are then submerged in flowing river water.

According to Yessylia, the moving water functions as a natural cooling system that stabilizes fermentation temperature.

Fermentation naturally generates heat. If temperatures rise too quickly, microbial activity may accelerate, producing undesirable flavors such as sharp acetic notes or overly fermented aromas.

By using river water to regulate temperature, producers can slow fermentation and maintain better control over flavor development. The result may combine the fruit intensity typical of natural coffees with a cleaner overall cup profile.

The Science of the Brew

Yessylia notes that grinder design and grinding speed can also influence particle distribution, including the amount of fine particles produced during grinding.

Washed coffees are often perceived as slightly denser and more structured in extraction.

Natural-processed coffees, on the other hand, can behave differently during grinding and brewing. They may produce more fines and sometimes dissolve more quickly during extraction.

Understanding these differences helps brewers adjust their brewing variables more precisely.

Thermal Management

Yessylia suggests experimenting with slightly lower brewing temperatures for certain natural coffees when bitterness becomes dominant.

However, the ideal brewing temperature ultimately depends on several variables, including roast level, grind size, and grinder performance.

Because grinding determines the particle distribution that controls extraction flow, the grinder becomes one of the most critical tools in translating processing characteristics into the final cup.

Yessylia’s Three-Pour Brewing Method

In her brewing demonstration, Yessylia uses a three-pour method with:

Brewing Parameters

• Grinder: Femobook A68
• Grind Setting: Second rotation, dial at 5.5
• Coffee Dose: 20 g
• Water: 280 ml

1. Bloom – 60 ml

A 40-second bloom allows trapped gases to escape and prepares the grounds for extraction.

2. Second Pour – to 180 ml

This stage gradually builds body and sweetness.

3. Final Pour – to 280 ml

The final pour completes the extraction while controlling total contact time.

According to Yessylia, this rhythm helps highlight fruit characteristics while maintaining clarity in the cup.

Sensory Outcomes

Processing differences can lead to distinct sensory expressions, even when the coffee comes from the same origin.

Washed Geisha

Washed Geisha coffees often display floral aromatics such as jasmine, accompanied by citrus or white grape notes. The cup typically presents a clean structure with bright acidity.

Natural River Flow Geisha

River Flow natural coffees may exhibit more pronounced fruit characteristics such as strawberry or tropical fruit. Compared with traditional naturals, they may also appear cleaner and more floral when fermentation is carefully controlled.

Femobook A68 & A5

Precision brewing depends not only on technique but also on the engineering of the grinder.

Femobook’s architecture focuses on near-zeror etention design and magnetic modular construction, ensuring that the grind settings chosen by the brewer translate directly into the cup.

Precision Model Comparison

For many brewers, near-zero retention is one of the most important engineering features.

This eliminates the need for purging between different beans, reducing waste while maintaining consistent extraction from one brew to the next.

Summary

Yessylia emphasizes that coffee flavor is shaped by a chain of decisions.

From farming and processing to roasting, grinding, and brewing, each stage influences how flavor compounds appear in the final cup.

Processing determines the bean’s chemical and structural characteristics.

Grinding determines particle distribution and extraction behavior.

Brewing technique translates these factors into sensory experience.

For home brewers and coffee enthusiasts, approaching different coffees with curiosity and flexibility is essential.

Small adjustments in grind size, water temperature, and pouring structure can help highlight the clarity of washed coffees or preserve the fruit character often found in natural processes.

Tools that provide consistent grind quality and precise control—such as the Femobook A68 and A5—can help brewers execute these adjustments more reliably. With stable particle distribution, low retention, and repeatable grind settings, brewers can focus less on correcting inconsistencies and more on refining flavor.