Understanding Coffee Blends
When we used to work behind espresso machines, we noted that a typical question that people would ask when they waited for their coffee was, “What blend do you use?” or “What’s in your blend?” That’s actually a pretty complicated question! You’d need a good 15 minutes to answer that properly.
The question of “What’s in your blend?” is complex because its correct answer needs to focus on not only the geographic areas that the beans in the mix derive from, but also the percentage of each bean in the mix and some discussion relating to their species. A truly comprehensive answer would also involve a comment on the degree of roast. More information than the humble accountant waiting for his coffee bargained for? You betcha!
Let’s look at each of the above components in turn.
 Mixing single origins: a blend is quite simply a mixture of beans from different countries. A blend can be in its simplest form a mixture of two different origins, say beans from Mexico and beans from Honduras. A very complex blend may be a mixture of beans from eight different countries (Muffin Break in Australia advertise on TV that their blend contains eight different single origins). Most typical blends that roasters create have about four beans in their blend.
 The percentage of each single origin in the blend is critical. For example, a Mex-Hon blend that has 50% Mexican and 50% Honduran coffee beans will taste far different to a blend that has 25% Mexican and 75% Honduran.
Coffee roasters will often keep the above information tightly under their hats. Like Colonel Sanders’ secret 11 herbs and spices and the fabled recipe for Coca Cola, information like this is a closely guarded trade secret.
 The species of coffee beans used in the blend is also pretty critical information when describing it. There are two main species of coffee tree that grow on plantations, Arabica and Robusta. Arabica coffee is coffee that grows on trees. Robusta coffee grows on a wild shrub or a vine, not so much a “tree.” The former is usually more expensive - quite simply because it tastes better than Robusta. However even though Robusta generally produces a bitter coffee that dries out a consumer’s palate, it is grown commercially as it is a key ingredient in instant coffee. But as we all know, there are exceptions to every rule. There are downright nasty Arabica coffees and truly beautiful robustas. An example of beautiful a robusta would be Indian Robusta coming from only certain plantations in that country. The flavour that these beans produce is strong without being bitter and their inclusion in a blend can boost character and flavour. These days I would welcome someone telling me that their blend had Indian Robusta in it, so long as the percentage of robusta in the blend did not exceed say 20-30%.
Robusta can often be distinguished easily in a blend. The beans are small and round, looking a little like a ball bearing. Arabicas are longer and look more like peanuts. They will not “roll” if they lie on their “crack” whereas a Robusta will roll over like a ball.
 The degree of roast relates to how long the beans have been roasting for and is usually determined by the colour of the bean. For example a light roast will be a very light shade of brown, a medium roast (where the beans have been roasting for longer) would be a rich, chocolate brown, a dark/full roast getting very dark brown, an Italian roast would be verging on black and a French roast very black and very oily. If you’ve ever wondered why the coffee in France tastes so shocking, next time you’re there just take a look at the colour of the beans in the hoppers that sit above the grinders on the café benchtops.
So if you’re working behind an espresso machine in a café and someone waiting for their coffee leans over casually and asks : “What’s in your blend?”, tell them that unless they have 15 minutes, you will give them a little more information each morning over the next week and then finally they might have their answer!
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