When it comes to coffee, many may wonder, ‘What’s the difference between coffee and espresso beans?’ Some people think they are a specific strain of bean, while others think that it’s a particular roast. Ultimately, it’s a blend (or a single origin bean) that stands up well under the high pressure preparation that is the hallmark of espresso extraction.
According to the aficionados at Home-Barista.com, ‘Espresso is almost always a blend of beans…The most basic rule of espresso blending is that espresso must have subdued acidity, be heavy bodied, and be sweet enough to balance the bitter and acidic flavors in the blend.’
To better illustrate how different beans might have different flavors (after all, coffee beans are coffee beans, right?), we’ll discuss some general information on basic coffee plants, tastes by region, post-harvest processing and, finally, roasting.
There are two varieties of plants, Arabica and Robusta. Arabica originated in Ethiopia, is typically grown in higher altitudes and accounts for 75-80% of the world’s production. Robusta, on the other hand, is a lowland coffee species that originated in West Africa. It features greater pest resistance and a generally heartier plant, which results in higher overall yields — but its high caffeine content gives it a intensely bitter and inferior taste. Some very carefully grown and processed Robustas can be found in premium espresso blends, however, as they can improve the crema and body. Additionally, human-initiated cross-breeding of Arabica and Robusta, which attempt to blend the low caffeine content and smoother taste of C. arabica with the heartiness and disease resistance of C. canephora, have resulted in new varietals which are highly adaptable, hearty and commonly used in commercial coffee plantations.
Depending on where they originate, the weather, temperature, altitude and soil contribute to different flavors; you can get a general idea of different tastes by region here.
Another element is how the coffee is processed post-harvest. Processes include natural or dry process, wet process and pulped natural.
Dry processing usually takes place in areas with limited rainfall and lots of sun light. This process allows the coffee cherry to air dry on patios before their skin and the fruit itself is removed from the coffee bean. The bean outcome is usually heavy-bodied, sweet and smooth with subdued acidity. It also can develop more crema during espresso extraction.
The wet process requires the cherries to be sorted in high pressure water tanks which then removes the skin but the fruit stays on the bean while it dries. These beans usually taste cleaner, brighter and fruitier.
Pulped natural uses a combination of the wet and dry processes. Beans grown in areas with low humidity allow them to dry faster without fermentation. The end result is a full bodied bean like those of the dry process, but with the acidity of a bean that has been wet processed. The bean usually is sweeter.
Once the coffee is grown, picked and processed, it’s time for the roast! Roasters create different blends with a specific flavor profile in mind. And, since coffee is an agricultural product that changes every season, they play a little mad science by swapping out different beans in the blend in order to maintain a consistent flavor over time.
Roasting occurs in a Four Stage Process: endothermic, first crack, pyrolysis and second crack. For more information on how different roasts inform the end coffee flavor, check out this handy chart, sourced from Kenneth Davids.
Hopefully, this primer provided you with some insight as you’re selecting a blend for espresso preparation. Got questions? Leave them in the comments and we’ll answer away!