Once you have developed a feel for how different coffees taste, you can combine them to enhance desirable elements and reduce aspects you don’t like. You can blend coffees from different countries or coffee beans processed with wet and dry methods. You can even blend two different roast levels of the same bean.
Why Blend
Commercially, blending is done for two reasons. First, blending can be used to achieve a uniform taste profile using beans from various estates. This is especially important when a signature taste profile is important for branding (think Sumatra or Java blends).
Despite what large coffee companies would have you believe, there is tremendous variety in taste within the coffee beans of a country or region. So many factors influence the final taste of the coffee beans that it’s impossible to isolate and control for them all. These factors include obvious ones like annual weather conditions, soil differences, and altitude. They also include the type of processing used on coffee cherries, how long coffee cherries sit before and after being processed, and storage conditions. Two coffee estates sitting next to each other can produce vastly different tasting beans. Large brands will buy both crops and blend them.
Second, blending can be used to highlight positive taste attributes of different beans while compensating for less desirable qualities. The Mocha-Java blend is an example of this. It combines the fruity taste notes of Yemeni coffee with low-tones of Java coffee. I should note that simply referring to “Java coffee” implies blending has already occurred to achieve a uniform taste associated with Indonesia’s biggest island. Another example of this is the ubiquitous Breakfast Blend.
For large brands, blends become signature tastes and the taste profiles or blend ratios can even be proprietary. Blending allows the brand to keep the same taste that customers have grown to expect even when weather or political conditions changes the supply of beans from a certain region or country. Blending can also help to reduce costs by allowing companies to mix cheaper robusta beans with arabica beans while preserving a particular taste.
For the home roaster, blending is more about experimenting to achieve a truly remarkable cup of coffee. You control all of the factors associated with your coffee, from blend ratios to roast levels. You can really hone your taste palate and play with all the aspects of roasting in a way not available to store-bought coffee drinkers. See if you can replicate a favorite brand, or develop your own blend to give to others as a gift.
Blending Starts With Cupping
Blending starts with a refined sense of the taste profiles for various coffee beans. Because of this, blending requires you to master coffee tasting, or cupping, first. For a detailed description of how to do a coffee cupping, click here.
Start a coffee journal. Keep track of tasting notes as you roast your beans. Take note of the origin of the beans down to the farm or estate. Note whether the beans are dry-processed or wet-processed. Write down your impressions of the taste and feel of the coffees. Over time, you will develope a sense of what you like and don’t about different coffee beans. Then you can start to blend beans to bring out their best qualities.
Ideas for blending
Include your blends in your coffee journal. As you develop a sense of what flavors you like and don’t like, you’ll be able to replicate the tastes with different beans. One downside to using fair trade or micro-estate coffees is that a particular bean may be out of stock the next time you order beans. You can use your journal and blending to compensate. Here are three ideas to get you started.
Base blend
This method starts with a solid bean as the base layer and adds other flavors to complement.
- 40% Java Sunda Mitra. Full body with lots of fruit and citrus flavors.
- 25% Papua New Guinea Kainantu Sero. Medium body and fruity tones.
- 25% Peru Caserio Buenos Aires. Less body, more cocoa and nutty taste.
- 10% Ethiopia Agaro Kedamai. Very bright.
Roasting level blend
This method involves blending the same bean but at two different roast levels. For example, use a cinnamon roast and a city plus roast. This method is easy to start with because it only requires one type of bean.
Mocha-Java Blend
As I noted above, this blend is one of the more well-known blends. The Mocha aspect comes from Yemeni coffee beans. Mocha, also known as Mokha, was once a major coffee port city in Yemen. The political situation in Yemen makes Yemeni coffee hard to come by, and the city of Mocha hasn’t been used as a coffee port for many years. But if you can find Mokha beans, combine them with a blend of beans from Java, Indonesia for a flavorful combination.
When to Blend
For the home roaster, there are two times to blend. You can blend together before roasting, or you can wait and blend them together after roasting. There are, of course, advantages and disadvantages to both methods.
Pre-Roast Blending
Blending beans pre-roast will ensure a thorough mix of the component beans. This is especially true if you’re using a drum roaster. As the beans rotate in the drum, they will mix completely to allow an even combination across the entire batch.
Pre-blend roasting allows you to ensure all batches receive the same level of roast, which can impact taste. I should note, however, that different beans will crack at different points. Pre-blend roasting is less time consuming because the two elements, mixing and roasting, will happen simultanenously. It’s also less time consuming because you only need one roasting cycle to achieve your desired result.
Post-Roast Blending
The advantages and disadvantages of blending post-roast are basically flipped from the ones for pre-roast blending. In other words, the act of blending will require more work on your part to ensure an even mixture. You can use a large mixing bowl and spoon and stir the beans by hand. You could even use your roaster’s drum and rotate the beans by hand to achieve an even mix.
On the other hand, blending beans after roasting allows you to roast each component bean to the highest quality. Different beans might require different roasting treatment to bring out their best flavor. You can roast larger beans and smaller beans separately, or give wet-processed and dry-processed beans different roasting profiles.
Blending post-roast does mean you’ll have to roast multiple batches before you can blend. You’ll need to label several storage bins to keep track of all these beans. And you’ll have to let your roaster cool between roastings, meaning this method will be more time consuming. One thing I recommend against is using different roasters to try to speed up the process. This introduces too many variables into your experiment and will make blends extremely difficult to replicate a second time.
Which Coffee Blending Method is Best?
Home roasters are usually working with small batches of a pound or less. For this reason, it’s largely a matter of preference. Home roasters with time on their hands should try post-roast blending. Roasters with limited storage space or time may want to opt for pre-roast blending.
Regardless of which method you use, the small batches typical of home roasting do require a high degree of precision in measuring your blend components. In a pound of coffee, the difference between 40% and 25% is less than 2.5 ounces.
Use a high quality kitchen scale and measure using grams, which will give you a more precise measurement than ounces. Remember that coffee beans lose weight during roasting. For that reason, make all your calculations either pre-roast or post-roast depending on the blending technique used.
Argument Against Blending
Some purists argue against blending at all. Each coffee estate’s product has its good and bad notes. Blending obscures these origin differences. You can learn to appreciate the subtle differences of various beans. You can also learn to change the taste of a bean by altering your roasting profile to bring out its maximum potential. I say don’t knock it til you’ve tried it. There’s no right way and no wrong way to do this since you’re the ultimate judge of what coffee works for you.