Why does this page exist?

Every time I visit a new city, I always have some lengthy paragraph of stuff to say about the coffee world there. If you know me, if we’re going to be talking about coffee, it’s going to be specialty coffee. It’s hard to explain the whole idea of specialty coffee without taking up a big chunk of the blog, which is exactly why I decided to create a dedicated page about it. However, because I’m aiming to fit a lot of things about coffee on this page, it won’t go too in-depth with everything.

Table of Contents

1. Countries of Origin
2. Species of Coffee
3. Coffee Varietals
4. Processing
5. Roasting
6. Resting
7. Brewing
8. Espresso
9. Percolation Brewing
10. Immersion Brewing
11. Closing Notes

Countries of Origin

Coffee likes to grow in tropical environments with stable temperatures, so we often see them growing in parts of the world like Brazil, Peru, Ethiopia, Kenya, Vietnam, and even in Yunnan, China these days. These coffees all have unique flavour profiles respective to their regions.

Higher altitudes generally lead to slower cherry maturation, which allows more time for sugars and complex flavours to develop. These higher elevation coffees also tend to have brighter acidity and more aromatic complexity. Lower elevation often gives milder, earthier, and less acidic coffees. Of course, when it comes to plants, soil plays a large part. In regions like Ethiopia and Central America, volcanic soil (rich in potassium and phosphorus) is quite beneficial for growing coffee. The composition of soils (and hence, their nutrient density), affects bean density and sweetness, with slightly acidic soils (pH 6-6.5) being ideal.

Species of Coffee

Ever seen the words “100% Arabica” plastered all over a coffee shop or a bag of coffee beans? Arabica is just one species of coffee out there in the world. Unfortunately, Arabica also holds roughly 60-70% of the market, and Robusta holds another 30-40%. This leaves just 1-3% for smaller species like Liberia and Stenophylla. I think it’s unfortunate because the smaller market-share coffees could be carrying some seriously interesting flavours that we’ve been missing out on. See Coffea Stenophylla, known as the “Forgotten Coffee”.

Let's talk about Arabica and Robusta.

Coffea Arabica, known for its aromatic and sweeter taste, is considered a mild and smooth coffee. The species requires a cool subtropical climate and must grow at high elevation (1000 - 2000 meters). Compared to Robusta, its crop yield is lower. On top of this, it's more susceptible to pests and rust (fungal infection).

Coffea Canephora, or simply Robusta, is generally known as the "stronger coffee" (more caffeine) of the two. It’s more bitter, has a thicker mouthfeel, and is much lower in aromatic qualities. Robusta is quite robust when talking growth conditions, requiring lower elevations (0 - 700 meters) and reproducing even in harsh environments and climates. It’s also rust-resistant, has double the caffeine (less pests), and even has a higher crop yield.

All things considered, Robusta seems like it should take the top spot — it's hardier, higher in caffeine, and easier to grow. But Arabica’s superior flavour profile is the main reason why it holds nearly twice the market share of Robusta. Robusta is also more bitter and has greater astringency, which makes it less appealing for high-end brewing. Instead of specialty coffee shops, we often see Robusta used in instant coffee or commercial blends at large chains.

Coffee Varietals

Coffee varietals are the sub-groups within a species. Think of how one type of apple tree might produce red apples, but another grows green apples. These different varietals of coffee give the producer the opportunity to grow cherries for a specific tasting note, sweetness, nuance, and body. Where the coffee is grown, and in what conditions, are important factors that influence the flavours of the coffee cherry. The following are just a few popular varietals today.

Processing Raw Coffee

Great job - you’ve successfully grown a batch of some high-quality coffee cherries. But now we have to process them; get them to a state where we can start to roast these coffee beans. Coffee processing removes the coffee seed from the pulp, mucilage, and parchment.

There’s three main coffee processing methods these days: natural, washed, and honey processes. Each of these methods change the sweetness, body, and the acidity of the coffee.

Washed

Coffee cherries first undergo a density test, where cherries that sink in water are chosen. These cherries are depulped (all non-bean parts are removed) and set to ferment in a tank of water from anywhere between 18 to 72 hours. This fermentation stage helps to break down the cherry’s mucilage, changing the bean’s flavour profile. The beans are now set to dry until they reach a moisture content of around 11%. Washed coffees tend to have a bright acidity with white wine undertones. Think citrus, floral, green apple, and tea.

Natural

The natural, or dry, process involves spreading the coffee cherries in a thin layer across a flat surface under the sun. For 3 to 6 weeks, farmers rake the beans back and forth throughout the day to prevent mold. During this time, the coffee beans ferment, allowing the sugars and mucilage to latch onto the beans. Once they reach 11% moisture levels, the beans are depulped and then stored. Natural coffees often have fruity and sweet tasting notes. Common descriptors include berries (blueberry, strawberry, etc), tropical fruits, molasses, and dark chocolate.

Honey

When done correctly, the honey process combines the best of washed and natural processes. The process involves depulping first, leaving a small amount of mucilage left on the beans. Once dried, the remaining mucilage is removed and the beans are stored. Oftentimes, honey processed coffees are referred to by colors - black, red, and yellow. These colors are often how much mucilage is left on the bean after depulping; black with the most, and white with the least. Yellow honey gives mild fruit, citrus, and floral; red honey gives a sweeter red fruit and brown sugar; black honey is the sweetest, having jammy fruit and a full body flavour.

Once processing is complete, the potential for flavour is set - no new flavours develop in our bean from this point on. What follows from here though, is the highlighting of these flavours and tasting notes through roasting and brewing. Let’s grab our bag of green beans and move onto the next section.

Roasting Coffee

Roasting coffee is an incredibly complex task; you need to know the bean density and hardness, preheating, airflow patterns, drumspeed, cooling, and so many more variables (RoR curve?? Development time???). To be honest, roasting beans is far above my coffee nerd paygrade, so here’s just the basics.

During roasting, green coffee beans are poured into a large rotating drum filled with hot air. The air ensures even heat distribution, while the spinning drum keeps these beans moving so they roast uniformly such that they don’t burn. As these beans heat up, they change physically and chemically; at around 196°C (385°F), a popping sound called the first crack is heard. This signals that the beans have reached a light roast. From here, roasting longer produces a medium roast (often ending before the second crack), and dark roasts go well into the second crack or past it (around 224°C / 435°F).

Light

The choice for specialty coffee - light roasts preserve the bean’s origin and process characteristics. Compared to the darker roasts, these coffees have more acidity and can offer more unique flavours as they haven’t been roasted away.

Medium

The step between light and dark roasts. It’s a common roast profile with a more rounded flavour profile. While this roast still preserves most of the unique flavours, it starts to develop more of the “standard” bitter coffee taste. A darker medium roast is sometimes called a “city roast”.

Dark

Low acidity, heavy body, and thicker mouthfeel. Has very little of their origin characteristics left, but pronounced smoky and nutty flavours of these coffees are enjoyed by some. Pro tip, if you're in Japan (particularly around Nagoya), try to find a cafe that serves Ogura toast. Medium-dark and dark roasts pair incredibly well with these thick slices of toast, lathered with butter and sweet red bean paste.

Now I might be a little biased, but doesn’t light roast sound great? It preserves the natural characteristics of coffee and it’s a whole lot less bitter. Unfortunately light roasts lose when it comes to financial cost. In terms of shelf stability, while dark roasts degas faster (release CO2 more quickly; too much loss = loss of flavour), that also means they achieve a flavour equilibrium sooner. Dark roasts also mask inconsistencies, making it easier to cover up lower-grade beans with dark roast’s characteristic bold, bitter, and smoky notes. The consistency of dark roasts make it the optimal choice for commercial coffee companies like Starbucks, Tim Hortons, and instant coffee manufacturers. Even in brewing, dark roasts are more forgiving; they’re less sensitive to grind size or water temperature variations, which helps to ensure a decent cup without trying too hard.

Because companies have been preferring dark roasts for most of the history of coffee, people have eventually come to associate the flavour of coffee to that of a dark roast. It also came with the unfortunate notion that darker and more bitter coffees are stronger, which is untrue; roasting for longer doesn’t magically create more caffeine, and in fact actually burns some of it off.

Watch James Hoffman’s video on roasting for a more thorough understanding of the whole roasting process.

Resting Coffee

Before your freshly roasted coffee can be used, we must go through a process of resting it. We do this because the coffee, after its long journey to get to this point, is tired and must take a little break before becoming hot bean soup in your cup. Probably not. When green coffee is roasted, it releases moisture and traps pockets of CO2 inside the bean. As time passes, the beans gradually degas and the CO2 escapes. This is the reason why many coffee bags come with a small circle in the back; a one-way valve to release gas. I mentioned earlier that too much loss = loss of flavour, but also if there’s too much CO2, we get a very sour and highly acidic flavour in our coffee. It’s for this reason coffee is generally rested anywhere from 7 to 14 days past the roast date, though some roasters might recommend some other range. You’ll notice that specialty bags of coffee will list the roast date rather than the best-by date because it's inherently more useful info to have if you want the best coffee.

Brewing Coffee

When it comes to brewing our coffee, we have a lot of options, but I'll only be covering the main three. I’ll cover these methods very briefly, and dive deeper into them after.

Espresso

When you take a bit of finely ground coffee, pack it down tight, and push hot water through it at about 9 bars of pressure, what comes out is a small, intense shot of coffee called espresso. Generally 16-20 grams of coffee in, and 32-40 grams of liquid out for a double-shot. People drink this as is, or combine it with various ingredients to get a drink they might prefer. More on this later.

Percolation Brewing

Percolation brewing is a more hands-on method where hot water is poured over coffee grounds and allowed to drip through, producing brewed coffee one drop at a time.

Immersion Brewing

With immersion, the coffee grounds hang out in a tub of hot water, slowly releasing its flavour. Like steeping tea, once finished, the grounds are separated out and a cup of joe is produced.

Espresso

Espresso is actually a recent revelation when looking into coffee’s history. Coffee is believed to have been first made in Ethiopia in the 9th century, but espresso only came into existence around 1900. Brewing espresso can be quite the task depending on how deep into the coffee rabbit hole someone is. At coffee shops where baristas can’t afford the time, they will most likely simply grind the coffee into the portafilter basket, tamp it (flatten the mound of coffee and compact it), and throw it into the machine for its 9 bar shower.

Coffee nerds like yours truly follow a much more complicated process. A lot of tools and variables come into play when pulling a shot. Dialing in the brew isn’t something I’ll go over in this article, but to satiate your thirst for knowledge, I’ll list off a few things that we might be interested in.

Finally, a shot of espresso is born. It’s beautiful; the rich orange crema and how dense it looks, the way it mixes into the espresso. Remember the part about degassing after roasting? Crema is actually the CO2 from the beans. The fresher the coffee, the more CO2 is generally produced - but as explained before, crema being CO2, can actually make the coffee taste sour if there’s too much of it.

Some people like to enjoy espresso as-is, but I find that adding some steamed milk can help to bring out the tasting notes that are otherwise buried behind espresso’s strong acidity/bitterness. Milk, when warmed to around 60 C, becomes sweeter and smoother as a result of its lactose breaking down into simpler sugars like glucose. But past this point (70 C+), the milk proteins can break down and start to produce sulfurous, egg-like odors. Steaming milk is also a topic that I don’t plan on going over here.

With this steamed milk, we can make a lot of drinks. Lattes, macchiatos, cappuccinos, flat whites, cortados, etc are all simply espresso + steamed milk. What differentiates these is the ratio of espresso to steamed milk. Lattes are generally a 1:3-4 ratio of espresso to steamed milk. Smaller drinks like cortados use a 1:1, but drinks like cappuccinos are 1:2 and with a lot more milk foam. Other popular options include ice cream (affogato), whipped cream (espresso con panna), water (americano), and even with ladyfinger biscuits to produce tiramisu.

Percolation Brewing

Also referred to as drip brewing/coffee or a pour over, hot water is added in stages over a period of a few minutes along with some sporadic agitation to improve extraction. Popular brewing materials for percolation include Hario’s V60 Dripper, or the Chemex. The grind size for percolation brewing is larger than that of espresso, but generally the same total amount of coffee is used to get a cup of coffee (pour over typically uses 5-6 grams per 100 mL). Percolation brewing has its own complicated variables like what shape the cone is, blooming, filter quality, agitation methods, and even how to pour the water into the bed of coffee.

As a quick note, blooming is the first pour in brewing, where just enough water is added to cover the coffee grounds to release CO2 from the grounds for better flavour later.

Immersion Brewing

Immersion brewing is all about letting our grounds soak and sit. The french press is the name of the game when it comes to this - just dump in the coffee and add hot water. All the grounds stay in contact with the water the whole time, which makes extraction more even and a bit more forgiving if the grind size or timing is off. Like with percolation brewing, there is also a blooming stage at the start. When brewing is complete, the french press comes with a handy plunger that pushes all the grounds to the bottom. Since the french press uses a metal mesh here instead of paper filters, the cup tends to be bolder, with more oils and a thicker mouthfeel. Lately, companies like Hario have introduced products like the Switch that combine the best of percolation and immersion brewing by attaching a valve to the bottom of the cone to restrict the flow of water.

Various other brewing methods exist like coffee socks, cezve (Turkish coffee), cold brew, siphon, phin filter (Vietnamese drip coffee), and so many more. If you’re out and come across a new brewing method, try it out! In a world where espressos and pour overs dominate the market, sometimes a Vietnamese egg coffee can hit the right spot.

Closing Notes

There’s still so much I haven’t been able to cover in this overview. I do want to write about how I find cafes, what I look for when buying beans, and a deeper dive into dialing in espresso. This is my time writing about one of my hobbies, so I hope it was somewhat easy to follow. It’s hard to determine if I’m giving too much detail or not enough. I’ll come to learn the more I write, so do stay tuned!

If there’s any takeaway from having read all this, I hope that it’s an understanding that coffee is much more than a bitter drink that people deal with just for the caffeine. There’s a world of flavour that just needs to be explored and if you’re just getting started with coffee, I’m getting excited for you because there’s so much to experience and enjoy.