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What Is Coffee?

You drink it every day, but how much do you know about coffee?

by Maciej Kasperowicz | June 05, 2019

Coffee is a part of our everyday life, so why do we know so little about it?

Coffee is easily one of the most popular beverages in the world, but it’s also one of the least understood. When confronted with the question of what coffee is actually made of, many people (at least those not in coffee growing countries) have no clue, and the words we often use to describe it, like, in English, “coffee bean” just lead to further confusion. So, to start our Summer School coffee education series from the beginning, let’s answer that very basic question: What is coffee?

Perhaps one of the main sources of confusion in coffee (and this one holds true in most languages), is that, like tea but unlike most other drinks, we use the same word to refer to the drink coffee as to the thing that the drink is made of. For example, we know wine is made from grapes, beer is made from grains and usually hops, and we add the word “juice” to most fruits to designate their drinkable form. Whereas coffee is made from... coffee. So the simplest answer to “what is coffee?” is “the brown drink we make from coffee beans.” But your fourth grade teacher wouldn’t really accept that definition, so we need to go further.

Okay, what are coffee beans? First of all, they’re not really beans, in the sense that they’re not in the same family as kidney beans, chickpeas, or any other kinds of legumes (and using the same word as we use for legumes for coffee is not something that’s done in, for example, Spanish or Italian). Coffee beans are actually the seeds of the cherry of a flowering shrub that grows in the tropics. Coffee comes from the fruit of a plant. Let’s get into that plant a little.

Coffee shrubs are part of the genus coffea, and while there are well over 100 species of coffea, we get the overwhelming majority of our coffee (like way over 99.9% of it) from just two, Coffea arabica and Coffea canephora. Most of what we call “specialty coffee” deals with Arabica beans, because those simply taste better, and even on many grocery store brands, you’ll find the label “100% Arabica” as a marker of quality. Arabica gets further broken down into varieties, which you know all about if you’ve ever paid attention to what kind of apples or wines you buy. In the same way that Macintosh, Pink Lady, and Honeycrisp are all different apples or Chardonnay, Cabernet Sauvignon, and Chenin Blanc are all different grapes, Arabica coffees come in varieties like Bourbon, Caturra, Gesha, and SL-28 that can all taste different from each other.

If Coffea canephora sounds unfamiliar, you might know it better as robusta, which is actually the most common variety of the species canephora —hence why the terms get used interchangeably. Robusta can be more caffeinated and easier to grow than Arabica, but the vast difference in flavor, especially its bitterness, makes it mostly undesirable for specialty coffee. There are wonderful hybrid varieties that use some robusta DNA to improve the growth potential of delicious arabicas, but we’ll get to those another day!

coffee cherries growing on the branch

Back to the physical plant, because while they vary in factors like height, width, leaf shape, and how many cherries can grow on one shrub — as well as other, more complicated factors — coffee shrubs all have a lot in common. They’re flowering plants, which means that once a year aromatic, usually white flowers appear on the branches. Afterwards, cherries will grow in place of those flowers. Once they ripen, those cherries are usually a deep-red color, though there are certain varieties that ripen to yellow, orange, or purple. Knowing that perfectly ripe color is important, as it allows coffee pickers (if well-trained and given the correct instructions) to only pick cherries off the trees when they're ripe and save the unripe ones for later, which will drastically improve the flavor we get from that coffee.

Unlike a regular cherry (which this plant isn’t closely related to), the coffee cherry usually has two coffee seeds growing inside, with notched flat sides that face each other. Those seeds take up way more space inside the fruit than the kind of cherry you’re used to, which, along with the relative hardness of that fruit, explains why coffee fruit isn’t a thing people really eat (as a vocab aside, fruits like coffee, cherries, peaches, and avocados, with a hard seed in the middle, are also called “ drupes,” and that’s a very fun word to say). When you get past the skin and mucilage (another name for that fruit pulp layer), the seed is surrounded by a protective layer we call parchment because of its texture when dried. Inside that parchment lies another very thin protective layer called silverskin, and finally we get to the seed. And that seed, after it has been separated from the fruit, dried, sometimes shipped across an ocean, and then turned brown in a roaster, is what we consume as coffee.

The word “coffee” has to do a lot of work. It’s a drink. It’s a plant. And even within those two definitions it exists in so many different states it can make your head spin. But knowing where coffee starts and where it ends puts you in a great position to begin understanding the journey in between, and why all these wonderful coffees can taste so different and unique.