Different coffees are blended together for several reasons. The most important one is to increase the quality of a less expensive coffee. High-quality Arabica coffee has a clean coffee flavor, very good coffee aromatics, and a smooth aftertaste, but it comes at a high price. Arabica coffee can be blended with other, less-expensive coffees so that the resulting coffee blend maintains most of the quality of the Arabica coffee, but at a lower price-point.
Another reason to blend coffee is to achieve consistency across coffee crops. A specific coffee genus can vary in taste when grown under slightly different conditions (soil, climate, altitude, etc.). Blending the crops achieves a consistent taste in the coffee.
Coffees are also blended to create unique coffee flavors, which can become "branded" in people's minds as specialty coffees. For example, Starbucks uses a blend that is a well-guarded secret in the coffee industry. But the taste of Starbucks coffee is unique. The Starbucks brand also connotes a coffee with a high caffeine content.
Obtaining a truly distinctive taste in a coffee blend may require as many as five coffees. To "design" a coffee blend having specific characteristics requires expertise in knowing the characteristics of the original coffees, and in understanding how the characteristics in those constituent coffees will work together in the final coffee blend.
Blending the coffee beans before the coffee-roasting process is easiest. However, all of the constituent coffees in the blend will be subject to the same degree of coffee roasting. If you have enough knowledge how the roasting process affects the characteristics of each constituent coffee, blending can be done after the roasting process. In this way, each coffee can be "custom roasted" so as to achieve a boutique flavor in the final coffee blend.
For example, "Melange" (meaning simply "mixture") is a coffee blend used for filter-drip coffee brewing. It consists of different coffees, each roasted to different degrees. This requires that the coffees be roasted individually.
If you want a dark roasted coffee flavor with an acidic coffee "snap" and good coffee "body," a mixture of 40% Colombian Tuluni coffee (roasted Full City style), with 30% Mexican Tres Flechas coffee (roasted French style), and 30% Kenya Estate coffee (roasted City style) will achieve this in the final coffee blend.
If you want a coffee blend to have a bittersweet coffee flavor with more moderate coffee acidity, you can try a blend of 60% Colombian coffee roasted Full City style, and 40% Kenyan coffee or Bright Central American coffee roasted City style. (Note that "City style" is a lighter coffee roast than "Full City" style.)
Another coffee blend used for filter-drip coffee brewing is the Mocha-Java coffee blend. Originally, the Mocha-Java coffee blend was made from Yemeni Mocha coffee and Indonesian Java coffee. Today, a Mocha-Java coffee blend is usually a combination of Indonesian coffee with either Yemeni coffee or Ethiopian coffee, blended 50/50.
Some other common coffee blends are Harar coffee with Sulawesi coffee, both roasted City style, and blended 50/50, and Harar coffee with Sumatra coffee, both roasted Deep Full City style, and blended 50/50. Note that in these coffee blends, since the roasts are the same, the coffee beans can be blended prior to roasting.
An Espresso coffee blend usually must be blended for balance so as to ensure a quality favorable for the final espresso filtre. Most Espresso coffee blends are based on high quality Brazilian Arabica coffee combined with African coffees or Central American coffees. These later coffees offer some acidity; a desirable trait of a good espresso. Robusta coffee is used to produce the "crema" and increase the espresso body.
For a sweeter or more aromatic espresso, Central American coffees (at most 25%) can be used in the blend. For more body, together with sweetness, Indonesian coffees (Sulawesi coffee or Sumatra coffee) will work nicely in the blend. An aggressive bite is achieved by using dry-processed Ethiopian coffee (about 25%) in the blend.
A very nice, smooth espresso coffee blend can is obtained by mixing: 50% Brazilian Dry-process coffee with 25% Guatemalan coffee, and 25% Colombian Wet-process coffee. A more aggressive espresso taste can be obtained by using 50% Brazil Cerrado Dry-process coffee together with 25% Sumatra Mandheling Dry-Process coffee, and 25% Ethiopian Sidamo coffee or Yemeni coffee.
For a good decaffeinated espresso, try 50% Brazil SWP Decaffeinated coffee together with 50% Sumatra SWP Decaffeinated coffee, or try 50% Sumatra Decaffeinated coffee together with 50% Ethiopian Decaffeinated coffee.
The number combinations possible is limited only by the imagination. Creating a distinctive coffee blend is a matter of deciding what characteristics in coffee most appeal to you, and choosing the constituent coffees and roasts to best highlight those characteristics.
...written by your friends at The Coffee Brewers