What Does Coffee Cleanliness Mean? Recommendations for Pour-Over Coffee Beans with Clean, Bright Flavor

Understanding Coffee Cleanliness: A Comprehensive Guide

A few days ago, FrontStreet Coffee discussed the flavor and body of a cup of coffee. Flavor is what most captures your attention, while body reflects the coffee's mouthfeel. The combination of these elements provides a multi-dimensional experience of coffee through your sense of smell, taste, and touch. Today, FrontStreet Coffee will explore cleanliness—a crucial aspect of coffee quality.

Cleanliness is Tasted, Not Seen

Typically, we associate cleanliness with clarity. For instance, a clear, translucent liquid is considered clean, while a cloudy, low-visibility liquid is deemed unclean. The same principle applies to coffee, but we assess it through our tongue rather than our eyes.

A coffee with high cleanliness maintains no unpleasant off-flavors or textures from the first sip through to the aftertaste. When you drink it, the flavors are clear and distinguishable. Generally, people's preferences for flavors tend to follow certain patterns—floral, fruity, and sweet notes are widely appreciated, while earthy, woody, rubbery, or medicinal flavors are typically undesirable in coffee.

The Impact of Coffee Bean Quality on Cleanliness

The emphasis on coffee bean quality began with the emergence of the specialty coffee concept, particularly with what we now call single-origin coffee. The off-flavors that most significantly affect coffee cleanliness cannot be resolved by adjusting brewing parameters when issues include immature beans, high quantities of defective beans, contamination during processing, or improper roasting.

Immature beans are unripe coffee cherries. Today, higher-quality coffee beans typically undergo full red cherry processing as a fundamental practice. However, in some regions like Brazil that use mechanical harvesting, the likelihood and quantity of immature beans tend to be higher at the green bean stage. These beans are difficult to identify when green but appear lighter in color after roasting. Such beans introduce astringency to coffee, compromising its cleanliness.

Other defective beans—such as insect-damaged beans, shell beans, and roast defects—can create bitter, unpleasant flavors and astringency, affecting the coffee's overall cleanliness.

Methods to Avoid Bitterness and Off-Flavors in Brewing

The bitterness and off-flavors that affect cleanliness during brewing are typically caused by (partial) over-extraction. When brewing coffee, here are some recommendations from FrontStreet Coffee:

Check the roast date before brewing. Coffee beans are not necessarily better when fresher. Within the first week after roasting, brewed coffee often exhibits noticeable harshness that can cause throat discomfort, affecting the overall coffee experience. Generally, coffee requires a resting period of about 4-7 days, after which the harshness subsides.

Coffee in an overly fresh state

Before brewing, examine the coffee beans and remove any defective beans (or beans you intuitively feel are not good). Although coffee beans undergo multiple layers of screening during production, some defective beans may still slip through. Some beans may also be crushed during transportation, requiring removal before brewing.

Poor quality grinders that produce excessive fine particles can also affect cleanliness. A simple solution is to use a sifter to remove these fines, though if you want more flavor complexity, you might reintroduce some fines. It's important to understand that the issue is "excessive fine particles" rather than "fine particles" themselves.

During brewing, use a gentler technique and avoid excessive "stirring" to improve coffee cleanliness. Another approach is to discard the final 10-20ml of coffee extract. Typically, after addressing the previous issues, any remaining bitterness and off-flavors are concentrated in the latter part of the extraction. Simply cutting off this final portion can resolve the problem.

Important Notice :

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