The coffee "bean" is actually the seed of a drupe called the coffee cherry. It's a tropical fruit, growing best within the Tropics of Capricorn and Cancer, also known as the Bean Belt.
There are multiple species of coffee, and within those species multiple varieties. The two main species that are used for cultivation are the flavorful and complex arabica, and the hardier and more caffeinated canephora (robusta). In specialty coffee, the industry that roasts and sells coffees that score an 85 or above on a 100 point Q-grading scale at origin, the main focus is on arabica and its varieties. Common arabica varieties include bourbon, typica, caturra, catuai, SL28, pacas, maragogype, and gesha.
Now, the variety of coffee is important, because it essentially creates the boundaries of what flavors are possible in the bean. A bourbon can technically only produce a certain combination of chemical compounds as it fruits, meaning its flavor is typically at least somewhat distinct from other varieties. It would be fairly difficult, if not impossible, to make two different varieties taste alike in the cup by growing techniques alone. So, think of the variety as something like the artist's palette: it holds the colors which the artist can use, in limited quantity.
When it comes to origin, coffee is a lot like wine: the environment in which it is grown makes a difference in the flavor of the crop. Higher altitudes create slower, more dense growth, which makes for more complex flavors. The right humidity can influence the sugar content of the bean, making for a sweeter cup. These are essentially like the artists' brush strokes.
Give a dozen artists the same palette, and they'll all create a unique work, but the colors will be the same. If you haven't yet, try to take the opportunity to see how distinctly different two regions can be for the same variety of coffee. The difference between a Guatemala Huehuetenango and a Guatemala Acatenango can be striking, and those regions are only miles apart.
For these reasons, many passionate coffee roasters, dedicated to quality, are involved in direct relationships with their growers, working together to create a better quality product from the source. These coffees are often more expensive, but to some (including many of us here on r/coffee) the price is worthwhile.
After harvesting, the coffee must be processed, and as you may guess, processing also matters. There are quite a few ways to process coffee, but essentially the steps are as follows:
Most coffees taste pretty similar at the extremes of roasting. Very light roasts taste grainy, grassy, and vegetal, whereas very dark roasts taste bitter, ashy, oily, and smokey. This is more or less true for any coffee roasted these ways. In the middle, there is far more room for nuance, but generally, the darker the roast, the less the coffee tastes like the coffee, and the more it tastes like the roast. There is no correct roast; there are only personal tastes.
In roasting there are a few distinct markers of roast progression aside from color, smell, temperature, etc. The big two are the first and second crack (or snap, or pop).
First crack occurs as the bean loses moisture, but begins to expand as the pores inside fill with gases. Being that coffee is a brittle structure of cellulose, the bean actually cracks under the internal pressure. Around the time first crack starts, chemical reactions within the bean's structure begin, in a process known as pyrolysis. At that point, the beans are actually giving off heat energy. This is also around the time where Maillard reactions and caramelization of sugars are taking place, or finishing up. At this point, most people would consider the coffee to be drinkable, and the roast can be stopped and cooled. However, it's still a fairly light roast, will have a pronounced tartness or sourness, and may not be universally pleasing. If you want chocolate or toasty flavors in your cup, you have to go a bit darker.
Second crack typically occurs just a few minutes after first crack stops. At this point, the moisture content of the beans is getting fairly low and most of the expansion has stopped. From here on, you're going from a brown color toward black and getting further away from the distinct qualities of the beans from those early stages of production. Right around second crack, you can expect to be getting more dark chocolate flavors, more dried fruit (raisin or prune, as opposed to a big juicy tart cherry), even some hazelnut, but the acidity will be largely tamed and most of the sweetness will begin to disappear.
After second crack finishes, you'll begin carbonizing sugars, destroying acids, and the beans will begin exuding oil from their surface as the pores contract. Even further and you're burning oils, charring the beans, and leaving very little flavor from anything but the roast. Past that and you risk combustion, as the beans are heavily carbonized, most of the CO2 has been cooked out, and you've got a very low-moisture environment.
After roasting, the beans are quickly cooled to room temperature. From here, opinions differ, but my finding is that coffee tastes fairly smokey and roasty for 12-24 hours post-roast, flavors peak between 3-5 days, and fall off over the course of 2-3 weeks, at which point I would call it stale. Once stale, it's not like the coffee is undrinkable. It's the same way stale bread isn't inedible, it's just not as pleasant as the fresh alternative.
Starbucks seems to habitually sell months-old coffee in stores, going by the Best-By-Date-minus-34-weeks model of guesstimating a roast date. Ground coffee goes stale even faster, so I'd never purchase a bag of ground coffee myself.
So there's a general idea of what goes into the production of coffee up to roasting and just before brewing. There is far, far more to learn about the whole supply chain, especially how farmers deal with pestilence and disease in their crops, what geopolitical hurdles there are, all the different processing methods and such.
There's a lot more to coffee than country of origin or roast level, so welcome to the rabbit hole my friend - be prepared to be falling for a long time.
There are multiple species of coffee, and within those species multiple varieties. The two main species that are used for cultivation are the flavorful and complex arabica, and the hardier and more caffeinated canephora (robusta). In specialty coffee, the industry that roasts and sells coffees that score an 85 or above on a 100 point Q-grading scale at origin, the main focus is on arabica and its varieties. Common arabica varieties include bourbon, typica, caturra, catuai, SL28, pacas, maragogype, and gesha.
Now, the variety of coffee is important, because it essentially creates the boundaries of what flavors are possible in the bean. A bourbon can technically only produce a certain combination of chemical compounds as it fruits, meaning its flavor is typically at least somewhat distinct from other varieties. It would be fairly difficult, if not impossible, to make two different varieties taste alike in the cup by growing techniques alone. So, think of the variety as something like the artist's palette: it holds the colors which the artist can use, in limited quantity.
When it comes to origin, coffee is a lot like wine: the environment in which it is grown makes a difference in the flavor of the crop. Higher altitudes create slower, more dense growth, which makes for more complex flavors. The right humidity can influence the sugar content of the bean, making for a sweeter cup. These are essentially like the artists' brush strokes.
Give a dozen artists the same palette, and they'll all create a unique work, but the colors will be the same. If you haven't yet, try to take the opportunity to see how distinctly different two regions can be for the same variety of coffee. The difference between a Guatemala Huehuetenango and a Guatemala Acatenango can be striking, and those regions are only miles apart.
For these reasons, many passionate coffee roasters, dedicated to quality, are involved in direct relationships with their growers, working together to create a better quality product from the source. These coffees are often more expensive, but to some (including many of us here on r/coffee) the price is worthwhile.
After harvesting, the coffee must be processed, and as you may guess, processing also matters. There are quite a few ways to process coffee, but essentially the steps are as follows:
- Separate the harvest by ripeness. Most fruit is hand-picked, and mistakes do happen. Machine harvested fruit will have a greater mix of ripeness, which is not ideal for optimal flavors. Separation can be done by hand or by using a gravity separator which dumps the harvest into a water channel, where the overripe coffee and some debris floats to the surface, and the ripe and underripe cherries, plus dense debris like stones, sinks. The floaters are skimmed off and typically composted, the sinkers are separated again using a steel plate with some varying sized holes punched into it, which dump the smaller underripe cherries and stones, but retain the plumper ripe cherries.
- The ripe cherries are then "depulped," meaning the seeds are squeezed from the fruit, still covered in a layer of parchment and some sticky mucilage. The seeds can then be washed further to rid them of mucilage, fermented naturally to increase sweetness, or dried as they are. The different processes at this point will influence the character of the flavors that end up in the dried green coffee, sort of a finishing step in the raw material production. Some farms will dry the coffee seeds within the cherries before further processing, typically referred to as "natural process" coffees. In any case, the final stages include removing the seeds from parchment and drying them to a desired moisture content, before packing them for shipping overseas.
Most coffees taste pretty similar at the extremes of roasting. Very light roasts taste grainy, grassy, and vegetal, whereas very dark roasts taste bitter, ashy, oily, and smokey. This is more or less true for any coffee roasted these ways. In the middle, there is far more room for nuance, but generally, the darker the roast, the less the coffee tastes like the coffee, and the more it tastes like the roast. There is no correct roast; there are only personal tastes.
In roasting there are a few distinct markers of roast progression aside from color, smell, temperature, etc. The big two are the first and second crack (or snap, or pop).
First crack occurs as the bean loses moisture, but begins to expand as the pores inside fill with gases. Being that coffee is a brittle structure of cellulose, the bean actually cracks under the internal pressure. Around the time first crack starts, chemical reactions within the bean's structure begin, in a process known as pyrolysis. At that point, the beans are actually giving off heat energy. This is also around the time where Maillard reactions and caramelization of sugars are taking place, or finishing up. At this point, most people would consider the coffee to be drinkable, and the roast can be stopped and cooled. However, it's still a fairly light roast, will have a pronounced tartness or sourness, and may not be universally pleasing. If you want chocolate or toasty flavors in your cup, you have to go a bit darker.
Second crack typically occurs just a few minutes after first crack stops. At this point, the moisture content of the beans is getting fairly low and most of the expansion has stopped. From here on, you're going from a brown color toward black and getting further away from the distinct qualities of the beans from those early stages of production. Right around second crack, you can expect to be getting more dark chocolate flavors, more dried fruit (raisin or prune, as opposed to a big juicy tart cherry), even some hazelnut, but the acidity will be largely tamed and most of the sweetness will begin to disappear.
After second crack finishes, you'll begin carbonizing sugars, destroying acids, and the beans will begin exuding oil from their surface as the pores contract. Even further and you're burning oils, charring the beans, and leaving very little flavor from anything but the roast. Past that and you risk combustion, as the beans are heavily carbonized, most of the CO2 has been cooked out, and you've got a very low-moisture environment.
After roasting, the beans are quickly cooled to room temperature. From here, opinions differ, but my finding is that coffee tastes fairly smokey and roasty for 12-24 hours post-roast, flavors peak between 3-5 days, and fall off over the course of 2-3 weeks, at which point I would call it stale. Once stale, it's not like the coffee is undrinkable. It's the same way stale bread isn't inedible, it's just not as pleasant as the fresh alternative.
Starbucks seems to habitually sell months-old coffee in stores, going by the Best-By-Date-minus-34-weeks model of guesstimating a roast date. Ground coffee goes stale even faster, so I'd never purchase a bag of ground coffee myself.
So there's a general idea of what goes into the production of coffee up to roasting and just before brewing. There is far, far more to learn about the whole supply chain, especially how farmers deal with pestilence and disease in their crops, what geopolitical hurdles there are, all the different processing methods and such.
There's a lot more to coffee than country of origin or roast level, so welcome to the rabbit hole my friend - be prepared to be falling for a long time.
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