Seven Key Factors Influencing Coffee Aroma and Flavor: Bean Varieties, Growing Environment, Roast Level, Processing Methods, and Brewing Techniques

As coffee enthusiasts, we know you can find an incredibly wide range of characteristics in coffee. From earthy tones to sweet fruity notes, floral aromas and tea-like qualities, our beloved beverage offers incredible taste experiences. But what determines these flavors that appear in your coffee?

There is no simple answer to this question. The science behind coffee flavor is still in its early stages, and we are just beginning to understand what happens at the chemical level. There may be factors we haven't yet identified, and no one can definitively determine how much each step in the coffee supply chain affects the final product. Nevertheless, there are some important factors that we do know now.

Most coffee enthusiasts could probably name some of these flavor-influencing factors off the top of their heads. Everyone knows that roast characteristics matter, and most of our customers tend to consider the origin as well. In this article, FrontStreet Coffee will introduce the different reasons for coffee flavors from the source where coffee is produced to the final step.

1. Variety

Even before the coffee-bearing plant begins to grow, there's one crucial factor that affects the crop—variety. This isn't as simple as Arabica versus Robusta (we generally recommend staying away from the latter). Within the Arabica species, there are dozens of known varieties, with more being discovered and created over time.

Wine enthusiasts will tell you that variety has a significant impact on what ends up in your glass. Cabernet Sauvignon has very different characteristics than Grenache or Riesling. Similarly, in coffee, the variety (or combination) in your cup will have a major impact on your experience as a drinker.

As Jono from Rosetta Roastery noted on a recent Coffee Brewmance podcast, many coffee enthusiasts might not give this important factor enough consideration and discussion.

2. Terroir

Whether you're talking about wine or coffee, terroir is one of those lofty terms that can alienate some people, but in reality, terroir is simply the influence of where the coffee is grown. We all know that Kenyan coffee tastes quite different from Brazilian coffee. We also know that coffees from nearby regions might have similarities. These are all results of terroir influence.

Of course, the specific factors of terroir conditions that affect coffee flavor are numerous and complex, but here are some important ones:

• Altitude
• Climate
• Soil type
• Soil microbiome
• Topography

We're certainly not suggesting you need to understand every element of terroir for every coffee you drink, but if you want to better understand your coffee, it's helpful to know where your coffee comes from and some defining characteristics of that terroir.

3. Farming Methods

As end consumers, one of the most important and perhaps difficult factors to grasp is that practices on coffee farms will have a huge impact on the taste of the coffee you drink. From chemical usage to planting patterns and pruning schemes, everything ultimately affects the nature of the crop.

One particularly important agricultural practice is picking. Like other crops, coffee is best picked at optimal ripeness, but of course, coffee cherries don't mature uniformly. This means that for the best results, cherries must be hand-picked by trained workers who pay attention to the ripeness of the harvested fruit.

Commercial-grade coffee is typically strip-picked (meaning all fruit on a branch is picked at once) or machine-harvested, which means the final product is a combination of ripe and unripe fruit. While this is cheaper, it doesn't produce high-quality coffee!

Other Resources:

• Wikipedia article on coffee production: https://en.wikipedia.org/wiki/Coffee_production
• The Perfect Daily Grind: Specialty vs. Commercial Coffee

4. Processing

After coffee cherries are picked, the coffee seeds must be dried before they can be transported and eventually roasted by local artisan roasters. The way this is done can vary greatly and has a tremendous impact on the final taste of the coffee. While this is a complex topic in itself, here are several categories to be aware of:

Natural or Dry-processed Coffee

Natural/dry processing is the traditional coffee processing method in Africa. In this method, coffee is actually dried while still in the fruit. The advantage of this approach is that it doesn't require large amounts of running water, and it allows more of the coffee's natural sugars to penetrate into the roasted coffee beans. Naturally processed coffees tend to be fruity and have lower acidity, but sometimes they are found to have less clarity.

Although this processing method might be more economical to execute, it carries a higher risk of crop corruption, and cherries must be manually turned frequently to minimize this risk.

Washed or Wet-processed Coffee

This more modern processing method involves simply fermenting coffee cherries and then removing the seeds from the fruit or pulp—"washing." The advantage of this method is that the outer fruity layer can eliminate some risk of spoilage.

Washed coffees tend to have higher acidity and greater clarity, characteristics that make them very popular in the third wave of coffee.

Honey Processing and Everything In Between

Recognizing that both wet and dry processing have their benefits, a third method or set of methods for processing coffee has emerged, aiming to balance the benefits of both approaches. In very simple terms, honey-processed coffees have some but not all of the outer layers of the coffee fruit removed during drying.

There are many different styles of coffee processing, usually referred to by the color of the final dried crop (yellow, red, black), and in most cases, they simply require removing different amounts of external mucilage.

Please note that not all processing methods fall neatly into these categories—see the additional resources below.

5. Roast Level

We might be entering more familiar territory here, but that doesn't mean we shouldn't carefully consider the impact of roast characteristics on flavor. Even the most talented roaster can't take inferior green beans and make them taste delicious, but an unskilled roaster can certainly ruin many good ones.

After sourcing and selection, the roaster helps realize the full potential of the coffee by carefully crafting a roast profile suitable for that particular set of beans. This isn't as simple as light or dark—on the contrary, roast color can be misleading. The roaster must fine-tune variables like roast time, charge temperature, rate of rise, drum speed, airflow, and cooling speed, while responding to data such as temperature logs, first and second crack times, and most importantly, sensory experience.

6. Blended Flavors

Decades ago, most coffee drunk in the world was blended. While this may still be true for the entire coffee industry, in the specialty realm, single-origin is becoming increasingly popular. This is likely because they allow drinkers to experience the fruits of the coffee farmer's labor (literally).

Nevertheless, blending itself can be an exquisite craft. In its basic form, it can ensure a more consistent flavor experience year-round as the blend inputs change with the seasons. At its best, a blend can be a unique taste experience where the flavors are more than just the sum of its parts.

7. Brewing

Last but certainly not least, brewing is the final stage of the soil-to-sip process, which also has an important impact on coffee flavor. A mistake new coffee enthusiasts often make is assuming that exactly the same brewing parameters will yield the best results in every coffee. "What's your AeroPress recipe?" is surely a common question among new enthusiasts.

Any barista will tell you that your brewing variables need to match the coffee you're brewing and the brewing method. In the case of espresso, they might even need to be adjusted in response to environmental conditions like temperature, humidity, and altitude. Even in simple manual brewing methods, variations in brewing variables can be the difference between decent and delicious.

Some important variables are:

• Brew ratio (water to coffee)
• Grind size (and uniformity)
• Extraction time
• Water temperature

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