Factors that affect coffee quality and taste

We know that there is a wide range of flavor profiles and differences in quality when it comes to coffee. They range from earthy and chocolate tones to floral and tea-like aromas. But what factors influence the taste of coffee? What contributes to coffee quality?

The quality of the coffee and its taste depend on numerous factors, e.g. B. on the variety (cultivar), the cultivation altitude, the climate, the soil chemistry, the harvesting and processing methods, the storage conditions, the degree of roasting and the brewing method. Here are 8 key factors that determine the quality and taste of coffee.

1. Genetic variation (variety)

There are around 120 known types of coffee worldwide. Coffea Arabica and Coffea Canephora (known as Robusta) are the two main species grown for coffee production and they have different characteristics. Arabica beans contain lower caffeine content but are richer in aromatics. They offer a balanced, smooth and sweeter taste with notes of chocolate, fruits and berries. Robusta, on the other hand, has a sharper, more bitter taste with earthy undertones. They are commonly used in blends as espresso coffee beans .

Even within the Arabica and Robusta coffee beans, there are many well-known varieties. Just as the type of grapes influences the taste of a glass of wine, the type of coffee beans also has a major influence on the taste.

2. The origin of the coffee bean (terroir)

In the world of coffee, it is generally accepted that beans from different origins have significantly different tastes: Have you ever noticed how different Ethiopian coffee or coffee from Burundi is from that from Brazil? Do you like Sidamo coffee from Ethiopia better than, for example, Bugisu from Uganda?

The differences in taste due to origin are due to the unique terroir of the respective location. Terroir refers to the different environmental factors that exist where the coffee is grown and produced.

The specific elements of the terroir that significantly influence the taste of coffee are diverse and complex. These factors determine the health of the coffee plant , whether the cherries ripen faster or slower , and the caffeine content , all of which combine to create a specific flavor profile. To understand the flavor profile and overall quality of the coffee, it is helpful to know the origin of the coffee and gain insight into the distinctive characteristics of the terroir.

3. Climate

In the “ coffee belt ”, i.e. in the areas above and below the equator, coffee is mainly grown as a crop. In this region there are often only two seasons: wet season and dry season. Coffee requires a perfect balance of sunlight, rain and temperature to produce high quality green coffee beans .

The Arabica plant is more delicate and requires special soils and climate conditions to survive; it usually grows at high altitudes with temperatures between 15 and 23 °C and an average annual rainfall of 1500-2000 mm. The frost-free , cooler climate at these elevations allows the cherries to ripen more slowly, allowing them to absorb more nutrients, which promotes flavor complexity and sugar development. Higher temperatures lead to faster development and ripening of the coffee cherries and thus to poorer quality of the beans.

The Robusta plant, on the other hand, is more resistant to disease due to its higher caffeine content (a natural pesticide) and thrives at lower altitudes with an average temperature of 24 to 31 degrees Celsius and more rainfall. As a result of these environmental factors, the bean is smaller and has a pronounced bitter content.

4. Altitude

At higher altitudes the temperatures are cooler than at lower altitudes. Lower temperatures lead to slower ripening of the coffee cherry. When the beans have more time to develop, more complex sugars are formed, resulting in more complex and subtle flavors. For example , Ethiopian green coffees are grown at altitudes of over 1,900 meters above sea level and are highly sought after because of their fruity and floral notes.

Arabica beans usually grow at an altitude of between 900 and 2,200 meters. As we can see, there is a wide range of elevation differences even among Arabica beans. As a rule of thumb, green Arabica coffee grown at higher elevations is of higher quality than coffee grown at relatively lower elevations.

Coffee grown at higher elevations also tends to have better drainage, allowing water to flow away from the plants. As a result, the coffee cherries remain denser, retaining more sugar and flavors.

Robusta beans, on the other hand, are usually grown at altitudes between 300 and 800 meters above sea level. Warmer temperatures at lower elevations encourage faster coffee growth and provide more harvest opportunities. However, this often results in inferior coffee with pronounced bitter flavors and lower acidity. This is one of the main reasons why Arabica beans are typically higher quality than Robusta beans.

5. Method of coffee processing

In coffee production, processing refers to a series of agricultural procedures that culminate in the removal of the green coffee from the harvested coffee fruit. For this purpose, there are three common processing methods, each of which has a significant impact on the taste of the coffee. They are natural, wet and honey.

Natural or dry process

The natural process involves drying the coffee cherries in the sun while the fruit is intact until it reaches a certain moisture content, usually between 11 and 12. Drying the coffee beans in the fruit allows the beans to absorb flavors from the pulp and skin as they dry.

The additional influence of the fruit material creates a more robust coffee. The fruity and sweet characteristics are more pronounced, forming aromas reminiscent of blueberries, ripe papaya or even dark chocolate.

In the natural processing method, the coffee cherries are dried in the sun with their fruit intact until they reach a certain moisture content, which is usually between 11 and 12 percent. During this drying process, the coffee beans in the fruit absorb flavors from the pulp and peel. This infusion of fruit material into the coffee beans contributes to a more robust coffee flavor. These coffees tend to be fuller-bodied and feature richer fruit flavors and sweet notes compared to washed coffees.

Washed or wet process

During washed processing, the coffee fruit is first removed from the peel and pulp. The beans are then subjected to fermentation to remove any remaining mucilage. The beans are then washed thoroughly until they are clean. Finally, they are dried on raised beds until they reach the desired moisture content (11-12%).

Wet-processed coffees typically have light acidity and a light to medium body.

6. Roasting process

Roasting is a transformation process that changes the appearance, taste and aroma of the coffee beans. The heat causes chemical changes in the coffee bean that caramelize the sugars and bring out the flavors of the acids and other compounds present. The roasting method and degree of roasting significantly influence the taste of coffee. The same coffee tastes completely different when roasted lightly than when roasted medium or dark.

Light roast

Light roast coffees have a light brown color, a light, light body, and no surface oil on the beans. Light roast coffees generally have sharper acidity than their darker counterparts.

Although a light roast makes the coffee taste fruitier, it is not suitable for everyone. Especially if you're used to dark roast coffee, the sharpness of the fruity flavor of light roast Yirgacheffe, for example, can be overwhelming.

Medium roast

The medium roast has a medium roasting time; The roasted coffee has a balanced sour, bitter and spicy taste. The aroma of the coffee beans is distinctive. East African green coffee beans , for example, are grown at high altitudes and are therefore dense/hard and have a better flavor than coffee grown at low altitudes. To bring out their natural sweetness and complexity, we prefer a medium to medium-dark roast.

Dark roast

Dark roasted coffees often have a dark brown color and a shiny finish, which is due to the presence of oils on the surface. In contrast to light and medium roasts, the coffee retains its aroma.

7. Freshness of the coffee bean

Coffee reaches its best flavor just a few days after roasting and should be consumed within 6 weeks of the roast date. The fresher, the better! After roasting, the coffee beans become stale due to exposure to oxygen, light, moisture and heat, so it is important to store the coffee properly. Check out our tips for keeping your coffee beans fresh .

Note: If whole beans are ground, they won't last long before they go stale. Grinding makes the coffee more susceptible to the factors that cause it to spoil. It is therefore important to grind the coffee just before using it.

8. Broths

Ultimately, the brewing process plays a crucial role in the taste and aroma of the cup of coffee. Although this is the final step in the journey from coffee plant to cup, the way the coffee is brewed can make all the difference. To achieve optimal results, the preparation variables must match both the type of coffee beans used and the chosen preparation method. Some important variables are:

Grinding degree

The coarseness or fineness of the coffee grounds should be tailored to the brewing method. Different grinds extract the flavors differently. If a cup of coffee brewed from high-quality beans is not strong enough and tastes sour , it may have been ground too coarsely. If the coffee tastes very bitter , it could be because the grind is too fine.

Water temperature

The temperature of the brewing water influences the solubility and the extraction rate. Too hot or too cold can result in an undesirable coffee. The ideal temperature for brewing coffee is between 91 and 95 degrees Celsius.

Brewing time

The length of contact between coffee and water should be optimized for the method you choose to achieve the desired taste. If you e.g. For example, if you are using a French press, 4-5 minutes should be enough for a balanced brew. If the extraction time is less than 3 minutes, the coffee will be sour and weak in taste. If coffee is extracted for too long, it contains a high concentration of organic compounds that can make it bitter.

Coffee-water ratio

The ratio of coffee grounds to water has a big impact on the strength and flavor of the brew. If you use too little coffee, the coffee may taste weak. However, if too much coffee is used, the brew can be too strong. Here you will find a coffee to water ratio calculator for different brewing methods.

Water quality

The quality of the water you use is an important but often overlooked aspect of coffee making. The quality of your brewing water, including its mineral content and purity, can affect the taste. If you use hard water, it cannot effectively dissolve the coffee particles, resulting in weak coffee.