Culture

Coffee Quality Assessment

  • By Green Sourcing and Quality Team
  • In General

Coffee Quality Assessment

Coffee quality assessment is a crucial part of the coffee industry, which ultimately determines the overall value of a coffee. To simplify things, the Specialty Coffee Association (SCA) has set comprehensive guidelines to standardize the assessment process. This ensures that each cup meets a certain standard, and facilitates a common language for discussing the subtle nuances of coffee quality.

Aroma and Flavor Profiles

The basics of coffee evaluation rests on two crucial elements: aroma and flavor, which are also the most immediately recognizable aspects of coffee. Aroma categories such as floral (reminiscent of flowers), fruity (evoking berries or citrus), herbal (suggesting fresh herbs), and earthy (similar to wet soil) are crucial for forming initial impressions when gauging quality and characteristics. Flavor deepens this experience, engaging the olfactory system with notes like citrus, chocolate, nutty, or spicy.

Besides the coffee's origin, variety, and processing method, the diversity in flavor and aroma becomes increasingly complex due to thousands of volatile compounds that are created during roasting - such as furans, which can impart caramel-like flavors, and pyrazines, which can contribute earthy tones.

The SCA grading system consists of some specific factors:

Acidity: Often measured on a scale from 1 to 10, good acidity gives a coffee bright, and vibrant character. While the ideal level of acidity varies depending on personal preference, it generally shouldn't be overbearing (like sour) for anyone. The pH level, usually between 4.85 and 5.10 (for Arabica), can indicate the level and type of acidity. Lower pH values correspond to higher acidity, which can be delightful when well-balanced but sour tasting if too pronounced.

A balanced acidity might remind you of a crisp apple or a fresh orange, only providing a pleasant sharpness that helps enhance other flavor notes without dominating them. For example, a Kenyan AA might have pronounced acidity resembling a zesty grapefruit, whereas someone less inclined towards acidity might prefer a lower-acidity coffee from Brazil or Colombia, which presents more nutty and chocolatey notes. The roasting process also affects acidity, where the lighter roasts tend to preserve more acidic properties than darker roasts.

Sweetness: Sweetness in coffee is critical as it balances acidity and adds complexity to the overall flavor profile. Primarily, it is influenced by the bean's natural sugar content, which ranges from 6-9% by weight in raw beans. Besides the natural growth and processing of cherries, the roasting process helps enhance the sugars, as the amino acids break down and sugars caramelize - all of which produces a range of flavors from subtle vanilla to deeply-rich chocolate that contribute to perceived sweetness.

Body: Described as the weight or thickness of coffee on the palate, body can be correlated with the concentration of dissolved solids in brewed coffee. This can typically range from 1.15 to 1.35% for most specialty coffees. When describing this character, the texture can range from tea-like and watery, to syrupy and rich. 

Fact - the body is greatly influenced by the brew method! For instance, a French press can highlight the tactile complexity of a coffee, due to its immersion brewing technique, which can introduce oils and really fine particles in the final cup. A characteristic like this particularly appreciated in crafting blends designed for milk-based drinks.

Uniformity and Cleanliness: In terms of grading, uniformity ensures that every cup within a batch tastes the same, while cleanliness refers to the absence of any off-flavors that could indicate defects or poor processing. Both are crucial for high-quality coffee, because it ensures a predictable experience. However, uniformity can be very challenging to achieve, with more exotically processed coffees, which might show more variation cup-to-cup than those that are natural or washed.

Aftertaste: Aftertaste, or finish, is the flavor residue that lingers a while after swallowing. A good quality coffee should have a pleasant and lasting aftertaste that prolongs the sensory experience and leaves the drinker wanting more. In our experience, this trait is often deeply tied to the coffee's origin, processing method, and the drinkers’ routine. For example, a washed Guatemalan might leave a crisp, clean finish, whereas a naturally processed Ethiopian could have a fruity, wine-like aftertaste that persists longer.

Assessment within the Supply Chain

Coffee is also assessed at various points, throughout its supply-chain lifecyle. 

Farm Level: At the farm, coffee is initially evaluated by farmers for basic sensory qualities and any visible defects. Farmers (sometimes together with local cooperatives) periodically conduct these assessments to sort cherries/beans, and identify any issues that could degrade quality, such as insect damage, mold, or irregular bean sizes. If the farm has the resources, a simple cupping session is also carried out to get a preliminary sense of the coffee's flavor profile. Very often, this stage is crucial for determining which coffees will continue through the supply chain and how they may be marketed.

Import Level: Once coffee is ready to be exported, it undergoes more rigorous evaluation. This typically involves sample roasting and professional cupping by certified Q-graders (trained and accredited by the Coffee Quality Institute) who evaluate the coffee against standardized criteria. These assessments are required to ensure that the coffee meets the specific quality standards demanded for international trade. The results generated at this stage influence coffee pricing, further handling, and even the branding of the coffee as it enters international markets.

Roaster Level: Once the coffees reach the roasting facilities, coffee is assessed again, this time with even greater detail. Roasters perform their own cupping sessions to thoroughly understand the coffee’s potential, along with its ideal client and use. In the specialty world, roasters at this stage spend long hours to develop roasting profiles that will best enhance the coffee’s inherent qualities. This stage is about fine-tuning. This final assessment ensures that the coffee will meet the expectations of customers, whether for specialty coffee shops or commercial consumers.

Conclusion

Simply put, grading coffee is a complicated business. It involves numerous steps and professionals, each contributing to guide the product in a specific direction. From the acidity to aftertaste, every sensory detail is analyzed to meet market demands. This industry-level complexity becomes almost necessary because the origin of the coffee, its roast style, and the chosen brewing method can all dramatically alter a coffee’s appeal. A washed processed-lighter roast coffee, for example, may be ideal for those who like vibrant flavors. A darker roast, on the other hand, for someone who enjoys richer flavor profiles. Brewing techniques like espresso or pour-over can magnify these complexities even more, affecting how coffee is ultimately assessed, prepared, and brought to buyers.

Yet, amidst these detailed evaluations and lengthy processes, there is a noticeable gap in assessing the impact of climate on coffee. 

No current standardized practices quantify how climatic conditions affect coffee quality or sustainability. This is a big problem, which impacts almost everybody in the supply-chain. However, via some global collaborations, specialty-coffee has started to draw inspiration from industries like wine and bourbon, where climate and environmental factors are integral to the product narrative and quality assessment.

Climate-Specific Grading Metrics: Just as vintners discuss vintage variations, coffee could include metrics for climate impact scores, clearly reflecting attributes influenced by growing conditions.

Long-Term Sustainability Indexes: Similar to how chocolate producers are increasingly focusing on sustainable sourcing, coffee could develop indexes that reflect sustainable practices at the farm level.

Blockchain for Traceability: Borrowing from industries like diamond mining and high-end bourbon, using blockchain to track coffee from farm to cup could also connect consumers to understanding how climate influences every harvest.

There is obviously lot of work that needs to be done. And by incorporating these approaches, coffee grading can evolve to also address environmental responsibilities. This could ensure that coffee is not just favored for its quality, but also for its adherence to ethical and sustainable practices.

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