If you’re looking for the basics of what you need to know about coffee, here is the first in a series of posts that will cover the essentials of coffee knowledge. I try to include summaries including the broad strokes, while also going into more detail for those who are curious.
That being said, it is a crazy long post, and I’ll break with standard formatting and tradition by including a table of contents for those who want to pick and choose.
What is coffee?
Coffee, the beverage, is water that has been filtered through the ground up, roasted beans from the coffee tree. The beans are found inside of the coffee cherry, the fruit of the coffee tree. The flesh of the cherry is discarded after harvesting.
Coffee beans are seeds, like all beans are, and were originally roasted before shipping because the producing countries didn’t want to send viable seeds. The roasting process destroys the ability to grow, but also renders the bean edible and significantly changes the flavor profile.
The resulting dark brown liquid is called “coffee” and is one of the most widely consumed drugs in the world. Before you challenge me on coffee being the drug, consider what is considered a drug, then what the active chemical actually is. They’re not always the same, such as the plant that was recently legalized in many states.
It’s so popular that it’s actually one of the most valuable trading commodities – 2nd only to oil.
Factor 1: The Beans
What strains of coffee are there?
There are two primary kinds of coffee plants: arabica and robusta.
Arabica is considered the premium bean and is more finicky when it comes to farming, which is where the name “robusta” comes from – the robusta tree is comparatively more robust and can survive in broader, harsher conditions than arabica. Robusta takes 2 years to mature; arabica takes 4. Robusta trees need to be cross-pollinated, while arabica is self-pollinating.
Arabica beans have a nicer flavor, but are lower in caffeine. Arabica has between 0.8-1.4% caffeine, while robusta has 1.7-4% caffeine.
The catch is that, when coffee was first being popularized in the west, they decided that robusta was garbage and not to be used unless in dire situations.
Robusta’s flavor is considered more woody or earthy, but its detractors say it tastes like grains, rubber, and that it’s too bitter.
Robusta makes up 40% of coffee production, despite its bad reputation. Who produces most of it? Vietnam. Why? Instant coffee, where people are less particular about the quality and often just want a buzz.
As well, it’s used to cut into blends that are mostly arabica because they’re said to add a depth of flavor and create a nice crema (the foam on espressos). Some believe this is just to lower costs, but these are arabica purists… and when can purists be trusted?
There are also some lesser-known kinds of coffee beans, but I have less experience with them and had a hell of a time even discovering this one: Coffea Liberica.
Liberica coffee originates from Western and Central Africa, and the name appears to come from Liberia, one of the countries of origin. It’s quite rare, but considered to be tasty and even considered “great” by some. Its primary use seems to be to help replace some of the Coffea Arabica plants that were killed by “coffee rust” – a disease that severely affects arabica plants and has threatened to wipe out some varieties entirely.
How does freshness affect flavor?
I once horrified a friend when, in university, I produced a bag of years-old coffee from the cupboard. It tasted like rust and acid.
Clearly, freshness matters quite a bit.
This is an area of disagreement among roasters and fanatics, but there’s one thing they do agree on: it does go stale, and the fresher, the better, broadly speaking.
Even that general agreement has some hairsplitting: some believe that you should age the beans a small amount after roasting. In my post on “What makes coffee taste bad”, I talk about what Boot Coffee Campus said about their findings. See the following chart:
As you can see, the middle of week two (Day 10) has the peak combination of both flavor and freshness. Freshness does not drop uniformly – the rate slows until it hovers near the bottom of the graph.
This information, however, is typically not from independently funded research labs, but is instead from citizen scientists that also double as roasters. They do have their own economic interests and drives, so keep that in mind.
However, letting it rest a short while could help increase the flavor if stored right, just like liquors, beers (“green beer” is a thing), and many other products. The logic is sound.
From what I can tell, and this is likely contested, light- and medium-roasts will fare the best for freshness over time since dark-roasted coffee has its oil exposed to the air. Oil exposed to the air will oxidize and turn rancid much faster. No bueno.
And in case you’re wondering how you can use this information, here’s the best information I could find on how long different forms of coffee last before going stale:
|Coffee Type||Storage State||Duration|
|Green Coffee||Unroasted, whole beans||6-12 months|
|Whole Beans||Airtight, opaque container, room temp||Declines from ~7-10 days after roasting; |
~1 month later it’s drinkable, but bad.
|Ground Coffee||Airtight, opaque container at room temp||~1 week, probably less.|
|Cold Brew Concentrate||No water added; airtight container||~2 weeks; flavors will change after a week.|
|Cold Brew||Water added||~3 days|
|Brewed Coffee||Open cup / To-go Cup||15-60 min (most say ~30, or until cold)|
|Brewed Coffee||Sealed Thermos||4 hours, then the oils turn rancid|
|Brewed Coffee||Milk added, open cup||30 min max; 1-2 hours in a sealed thermos|
|Espresso||Open Cup||Until the crema (the foam) disperses;|
|Milk-based Drinks||Open Cup / To-go cup||General agreement: milk shortens shelf life. |
Let’s say: until it gets cold. After 2 hours, avoid drinking
- General agreement: most coffee lasts until it gets cold
- Adding milk shortens the life of a cup
- The more processing of the coffee, the shorter the span
- Unroasted coffee lasts longest
- Ground, air/light exposed, roasted coffee lasts the shortest
- Brewed coffee, in any form, is at the shortest possible, particularly espresso.
What about Grind Level?
When it comes to grind level, the main thing is consistency. You will see this all throughout this document, but that is the main lesson.
When it comes to the rate at which water can absorb solutes from coffee is determined by a) the surface area of the coffee it is in contact with, and b) the amount of time and pressure the water is under.
Pressurization tends to speed up chemical processes, and coffee is no exception. Espresso coffee is one of the finest grind sizes (almost a powder), and the water is quite hot (increasing absorption rate), and pressurized (further increases the rate).
French press, on the other hand, requires a coarser grind because it is steeping the coffee, known as “immersion brewing”. This gives it more time, and thus it needs to be less fine. If the coffee is too fine, it will easily become over-extracted.
Over-extraction is taking out more than we want, including more unappealing, bitter, hollow flavors, or it can even be tasteless. Under-extraction means that the stuff we want from the beans have not been adequately extracted, usually resulting in a sour, thin, salty, or acidic flavor.
Now, what happens when we take coffee that is inconsistently ground – big, medium, and small chunks all mingling together in the same brewing process?
As you might imagine, the small chunks will be over-extracted, the medium chunks will be just right, and the big chunks will be under-extracted. Overall, it’ll result in a subpar cup that doesn’t accurately represent the quality of the coffee being used.
How do you fix this?
First off, never, ever use a blade grinder. They are bad, and they should feel bad when used for coffee. They basically bash the beans until chunks fly off, and do it at such a rate that it can actually burn some of the coffee through friction. Terrible.
Instead, you want a disc or burr grinder. Yes, they’re more expensive, but you can get budget ones for under $100 on Amazon. They should get you a much more consistent result, not to mention more control over the grind level. Much more room for experimentation!
Note on bean storage: Dovetailing with freshness – never store your beans in the grinder’s hopper (where the unground beans go), as they will be exposed to both air and light, reducing freshness. Measure and grind the amount you want before pouring it into the grinder. Grind only what you need for that time for maximum quality.
Note on flavored beans: if you have beans that are flavored, this means they’re usually coated in some sort of oily substance that’ll give it the extra flavoring. Never use these in your expensive grinder, as it will be next to impossible to completely eliminate them from the grinder’s innards, meaning it’ll taint your future grinds for months to come.
What’s the difference between decaf and caf?
The obvious answer is that decaf coffee is coffee without caffeine. How different it is from the original is dependent entirely on the process used to decaffeinate.
Caffeine is water soluble, meaning water can absorb it. However, water is not a selective medium, so it will pull out some of the 1000+ components in the beans that we want to leave for future enjoyment.
Instead, they use other mediums to extract the caffeine, such as CO2, methylene chloride, activated charcoal, and ethyl acetate.
All methods are used with unroasted beans and must remove 97% of caffeine in the US, and 99.9% in the European Union.
The most clever approach I’ve found is one that they will use one batch to soak in their liquid solution and pull out everything that the beans will give up – not just caffeine. They will then chemically treat the solution to pull out the caffeine but leave everything else.
Then this solution is reused to extract only the caffeine from the beans because it’s already saturated with the other components.
A clever workaround that leaves the treated beans with all their desired traits and no caffeine!
My personal belief/blasphemy: given all the effort put into keeping the flavor intact, blind taste testers will probably have a difficult time differentiating decaf from regular. According to some forums, they believe the flavor is largely the same, but decaf can lack body.
For more reading on decaf specifically, check out my post dedicated to it.
What’s the difference between instant and regular?
TL;DR of how instant coffee is made: they create a very saturated coffee, then use one of two methods to suck out all the water, leaving dry crystals of coffee.
The first method is spray-drying: using hot air jets to dry droplets quickly and evaporate the water.
The second method is freeze-drying: the concoction is frozen, cut into small pieces, then dried under vacuum conditions at a low temperature.
According to Healthline:
- Instant may contain even more antioxidants than regular.
- Instant contains less caffeine (surprising, given it’s largely made from robusta beans), with 30-90mg per cup; regular typically contains 70-140mg per cup.
- Instant has more acrylamide; a chemical you don’t want, but is so small that it’s negligible compared to other dietary sources, personal care products, and smoking. Just to be thorough, acrylamide is linked with nervous system damage and cancer. Again, it is not substantial enough to care.
- Instant contains all of the other benefits that coffee has, including enhanced brain function, metabolic boosts, reduced disease risk (particularly neurodegenerative ones and diabetes), improved liver and mental health, increased longevity.
Coffee purists will say that instant is only a last resort or restricted to specialty uses, like dalgona coffee. I think it has its uses in blended drinks and coffee-flavored beverages or foods.
If you come across someone who thinks something is completely useless for all situations, then they lack imagination.
What’s the difference between roasts?
When it comes to roasting, you want to develop certain flavors, while removing others.
Commercial roasting machines are often like a clothes dryer. The beans are held in a big drum that spins and treats it with hot air, making sure nothing stays still for too long in order to avoid burning.
People believe that you will lose the sweetness in darker roasts, and this may be a general trend, yes. However, in properly roasted dark-roasts, you caramelize the sugars.
The most common “roast levels” found are these three:
Light – Flavors are most distinct for the coffee. They are brightest and most acidic. From my other research, I found: low sweetness, full body, full aroma.
Med – More balanced and bold flavor, less acidic. Medium is recommended, as it has mild sweetness, full body, strong aroma.
Dark – Contrary to popular opinion, dark roasts do not have more caffeine than the others; some argue that dark roasts will lose caffeine in the roasting process. It’s said that this level of roast will leave you with more of the flavor of the roast and less of the unique attributes from the region and the bean itself. Full sweetness, full body, medium aroma.
However, there are more roast levels than just these three. If you want to get more details and a more thorough breakdown of the flavoring and roasting process, please check out this post dedicated to roasting at home.
Factor 2: Water
How important is water to coffee?
Before you roll your eyes, and even if you already have, consider:
Do you think that any water from any source will pull the best flavor and results out of any coffee?
Hell, some people don’t even find their tap water worth drinking straight, so the answer should clearly be a resounding “no” about all water being equal.
But fear not, you don’t need to install anything big, fancy, or expensive to improve your water quality.
Calcium and magnesium help to pull out the good parts of coffee, but there are diminishing returns.
Water also has a factor called “buffer ability” or “buffering”, which is its ability to maintain a neutral pH score (aka 7). If it has good buffer ability, then it can maintain its current pH without altering too much.
People generally believe (myself included before researching this) that if you add equal parts acid and neutral water, the pH will land exactly in the middle between the two. This isn’t the case in reality.
You may see some things talking about the “bicarb” or “bicarbonate” of the water, and this is also referred to as the “alkalinity” of the water. This is not the same as “alkaline”, apparently, which refers to how basic (high pH) something is. To be even more technical, water pH measures the hydrogen (acid ions) in the water; water alkalinity measures the carbonate/bicarbonate levels.
In short: Bicarb acts like a “sponge” to absorb acid without changing the pH of the water. If you were to continue adding acid, it’d oversaturate and change the pH. In this instance, we just want enough to control the acidity of the coffee a little.
If it’s too alkaline – too much bicarb – then there are no acids in it. It’s boring, flat, brown, still-water. Yuck.
How can you tell what’s in your water?
A TDS kit (Total Dissolved Solids) will tell you how much is in your water, but not specifically what they are. Could be calcium, magnesium, or some third variable that also conducts electricity.
An easier metric could be using a website, like EWG.org, to check your ZIP code to see what your water content is. Depending on your country and utility company, they will often provide you with a comprehensive breakdown of what’s coming to your pipes – if you ask.
A dropper kit is also a useful tool if you are certain the water has been treated or softened in some way. After adding the droplets to your water, it’ll change color and indicate total hardness and carbonate hardness. It’s not super accurate, but it’ll give you an indication of what you’re working with.
What levels should you be aiming for?
For calcium, 30-50mg per liter (ppm or “parts per million”) is considered good.
For magnesium, 15-30mg per liter should work.
There are also official coffee competitions that will tell you what levels they use for hardness, alkalinity, and so on. One such example is the SCA (Specialty Coffee Association).
But what about water filters, like Britas and such? They improve the taste of water if it has impurities (like chlorine) and can only soften it a slight amount.
I’ll repeat: Britas are unlikely to fix the problem because their effects are minor.
Why is hardness such an issue?
It’s not the flavor or hardness in itself – it’s the buildup of limescale in your equipment. Over time, hard water will damage, clog, or outright break your equipment.
If Britas don’t fix it, what will?
Commercial water softeners can help, but they’re much more expensive and essentially do the same thing as a Brita, just on a larger scale.
Then there are “reverse osmosis” filters, which basically press water against a mesh so fine that only H2O can fit through, and the rest runs off as waste. You’ll get water that’s almost entirely pure – which also isn’t desirable either. Remember the part above about bicarb and magnesium?
The minerals help in the absorption of desirable traits from the coffee. In addition, distilled water will actually pull minerals out of your body when you drink it, eventually depleting some of your body’s mineral stores. If you drank nothing but distilled water, you’ll eventually die (especially while fasting).
Finally, pure water can actually be corrosive to equipment in the same way it is for your body; it will constantly pull minerals from the metals in your machine.
If your water hardness is your primary issue, then a Brita will probably do the trick.
1) One of the most common, but least sustainable and least cheap, workarounds is the use of bottled water. In Europe, it’s required that they put the mineral content on the label of the water. In North America, it’s not so common. They’re a solution, but not a good one.
2) You could approach a small cafe nearby who takes their coffee seriously and treats their water. Ask them if you can buy some of their water, using your own jug. Not all will go for it, but if they do, it could be an affordable, sustainable approach that doesn’t break the bank and doesn’t need much effort.
3) Ask your roaster (supposing you buy from one) what their water is like. They should know the mineral breakdown, which can give you a target for your own water. If you can somehow copy their water composition, then you should get similar results and flavors as those they display on the bags of beans.
4) A more straightforward route: buy distilled water and a mineral water sachet to mix with it, like this. It’s also a good choice for those who want to hold that variable constant or to ensure that the water isn’t an issue. Looking now, it’s $15 for 12 gallons.
5) Finally, you could buy distilled water, Epsom salts (magnesium), baking soda (sodium bicarbonate), and combine them. The best advice one person gave was 1.3g baking soda and 4.2g Epsom salts for 5 gallons (18.93L) of distilled water.
While the last one may seem like a lot of work and precision, you only have to do it once every 5 gallons. The most expensive part is the distilled water and space to store a 5-gallon tank/jug.
To me, the best option to try would be the mineral water sachets to see if it makes a difference, then eventually upgrading to mixing your own if you notice a difference.
This is more than beginners would need, but for the sake of being comprehensive, here are charts made by Reddit User, Doc_Sevens.
These charts will be adding Epsom salts and Baking soda (in grams) to 1.89L of water to make a 10% solution. This means you’ll have half a gallon (1.89L) that can be mixed, 1 part solution, 9 parts water. For example, 50mL of the solution mixed with 450mL water.
Alkalinity: Adding Epsom salts (g) to 1.89L water for a 10% solution.
|Desired ppm Alkalinity|
|Initial dKH |
Hardness / Bicarb / Bicarbonate: Adding Baking soda (g) to 1.89L water for a 10% solution.
|Desired ppm Hardness|
|Initial dGH |
Factor 3: Equipment
What equipment is best?
This question is often asked, but it’s impossible to answer for everyone.
What clothes are the best? What car is the best? Even something as basic as “what’s the best way to drink coffee?” – you’ll never find answers to these things because the response should be “for what?”
Instead, I’ll address the most common machines that you’re likely to find at home.
Important Note: I’ll cover the strengths, weaknesses, and pitfalls as I see them and have read. Pitfalls are defined as ways that you can go wrong with the equipment and get worse results, i.e., common mistakes.
Reviews of the most common equipment types:
Drip Machine / Percolator
This is your standard, most ubiquitous machine in North America. It’s not the best coffee, but it’s also not the worst. It’s boilerplate coffee – your standard fare; nothing to write home about, except maybe to complain.
Percolators function by dripping hot water onto the ground coffee, which then slowly works its way through the filter into the coffee pot, which is on a hot plate. Largely automatic, there’s very little to do for the operator.
Put the filter and coffee in, fill with the desired amount of water, turn on, wait.
And that’s basically it. It’s easy to make coffee, and you can even program it to run at a certain time.
Strengths: It’s easy, it’s common, the required materials are minimal, and it’s easy enough to clean. Makes a lot of coffee; good for entertaining. I’m not sure I’d recommend using quality coffee in this method, but it’d be better than a tin of folgers.
Weaknesses: Makes middle-of-the-road coffee, and there’s little to do to affect the process.
Pitfalls: if you program it to make coffee in the morning, then your coffee will be sitting out all night getting stale. As well, most people don’t clean their machines as often as they should. Running it once a month with vinegar water should do the trick.
These have reached peak popularity a few years back (I hope), and fingers crossed it doesn’t continue increasing. I’d take percolated coffee any day over this.
One pod = a single cup of coffee. How much coffee is in one of those pods? Very little.
I have yet to thoroughly research pods, but part of me suspects that a portion of what’s contained is actually instant. I have no evidence other than the darkness of the coffee that results from such a small amount of beans.
In short, it is pre-ground coffee, and we can’t know how long it’s been sitting around.
They are packed in multiple airtight layers, but since none of them are bulging, we can expect that all of the CO2 had been let off before packaging. This means that it’s probably been stale since it was packaged.
The system works off of pressure, so they sometimes try to say that it makes “espresso-quality coffee”. That’s like saying that fillet mignon and reject cuts are the same because they both use beef and a grill. Don’t be fooled; the only parallels are that it is fast, and it uses pressure. (Imagine: “This beef shank makes fillet-mignon-style steak!”)
You’ll notice that the pitfalls are very few – the industry seems to have gone this route because it’s idiot-proof and very profitable. The “best” business model is selling the equipment, and then constant accessories/materials. Being a serious cash cow, it’s easy to see why several companies seem to be resistant to pods you can reuse and refill at home.
Strengths: Very convenient; easy to find; convenient for a single cup; cleanup is a breeze.
Weakness: Extremely wasteful; subpar coffee; expensive; you need a chunk of dedicated counter space for the machine; often doesn’t allow you to use your own beans.
Pitfalls: Needs to be cleaned semi-regularly, though the quality is low enough that you probably won’t notice for a long time if you neglect your machine.
This is one of my personal favorites, though I tend to drink too much coffee as a result.
This is an immersion method; the coffee hangs in the water for a certain amount of time. It allows for more control, since you control time, water, and the beans. Yes, this means it’s slightly more work.
I use one daily, and the extra work is in a few small areas.
- Grinding the beans – I do it every few days and store it in a small, airtight jar at room temp in a cupboard.
- Watching the clock – they recommend ~2-4 minutes for immersion, depending on your grind coarseness (Remember: coarser = longer).
- Cleanup: you don’t need to use soap every time, but usually just dumping the beans, rinsing the glass part out, and disassembling the filter so you can get all the beans out. Since you don’t want rancid old oils in with your new batches, it’s best to wash with soap. If you’re lazy, a good, deep cleanse once a week would suffice if you use it daily and rinse with hot water each time.
Given the extra control, you can make a much better cup. However, with control, you lose convenience. It is cheap, and the filters last indefinitely; manufacturers may disagree (definitely without vested interest /s), but generally, 6 months is recommended.
Strength: Far more control; can make a stronger cup; can make larger volumes (depends on your french press); fairly easy to clean; not too expensive; very little need for continual purchases (filters, pods, etc.)
Weakness: Fragile; not the best for larger groups; you may end up drinking more coffee (if that’s a weakness)
Pitfalls: You can over- or under-extract if you don’t watch the time or coarseness uniformity; it requires some experimentation with grind levels.
This is probably the cheapest, closest thing you can get to a homemade espresso.
The whole thing is on the stove, heating the water in the bottom until it forces steam up through the coffee grounds in the center compartment, which then collects the dense coffee in the top compartment. Ingenious, really.
It’s pretty easy, durable, and compact. You’d need finer-ground coffee for this one, as it is only being exposed to the steam for a limited time, so similar levels to espresso.
For ease of use, it’s quite good. There are no filters, but you have to make sure you thoroughly clean it after each use due to the same issue of rancid oils lingering, or lingering moisture rusting the equipment.
It also requires slightly more hands-on time, as you have to fill the water compartment, pack the coffee grounds into the coffee receptacle (the “filler plate”), then screw it all together and place it on the stove.
Over-boiling doesn’t post much risk if you step away for a minute, but it’s best to avoid the fire hazard.
The cup quality is fairly consistent but will depend largely on the quality of your beans and the level of grind.
Strengths: not much skill needed; fairly consistent, high results; the cheapest, easiest, closest thing to espresso you can make at home.
Weaknesses: Requires thorough cleaning with a toothbrush (including taking off any rubber seals); otherwise, it will start to produce worse and worse coffee.
Pitfalls: Not a deep or regular enough clean, allowing rust and rancid oils to build up and taint future results.
By far, hands down, my favorite coffee maker is the Aeropress. It’s compact, it’s durable, it requires very little in terms of filters, and can make your cup as strong or weak as you want it. Perfect for travel, and I missed having it when I forgot to pack it.
There are two methods of using it: one is percolation, the other is immersion. This means you can steep your coffee if you want, or you can just let it drip through at the pace of gravity. See #7 and #8 in this post for more detail.
Better still, if you’re in a hurry, you can use the plunger to force the water through faster, also making it easy for cleanup. Screw off the filter holder, hold it over the trash or compost, and pop the coffee puck out, filter and all. One quick rinse and onto the drying rack. So easy and good.
I honestly don’t know why this hasn’t beaten pods into extinction. I guess boiling your own water is too much of a hassle.
Strengths: Compact, durable, filters are cheap and last a long time; good control over the coffee, capable of making a quality cup; can be immersion or percolation; can add spices to change the flavor (cinnamon, etc.); extremely easy setup, cleanup, and maintenance.
Weakness: Must boil your own water; it’s made of plastic (polypropylene; BPA-free since 2014, but I personally avoid mixing plastics and hot liquids); requires filters (cheap, one package lasts months).
Pitfalls: It requires a little bit of coffee awareness to maximize results, but it’s hard to go too wrong. Since it can easily be taken apart, essential components may occasionally get lost if not careful or while traveling.
Similar in capacity to the Aeropress for customization and the ability to make a quality cup, only more so. It’s a percolation-style brewer that sits on top of the coffee receptacle (cup or pot) and flows water through a standard coffee filter, like those used in a drip coffee machine.
There are competitions to see who can make the best coffee by using the same beans for everyone. Each barista must choose the grind level, water temperature, and pouring method.
Believe it or not, just those variables are enough to taste the difference due to extraction. Personally, I’m not sure if I could taste the difference, but I’d give it a shot.
Its downfall is that the pourover equipment can be a little expensive if it’s ceramic, or flimsy and cheap plastic, which… again, not a fan of plastic. As well, it’s not very compact in most of its forms compared to the Aeropress, though it is much smaller than any machine.
But hey, some consider it the gold standard for making coffee. To each their own.
Strengths: relatively little equipment; relatively compact; ceramic, silicone, or plastic; sometimes collapsible (silicone); lots of freedom for the brewer to experiment; capable of making very good coffee. Easy cleanup.
Weakness: requires a bit more hands-on time and experimentation; uses large filters. Not much to complain about, I just find them clunky.
Pitfalls: If you have no idea what you’re doing, it’ll still come out alright. Ceramic ones are breakable. Not many pitfalls.
Very good for making European-style and white coffees (lattes, cappuccinos, and such). It’s the only legit way to get a quality espresso, but it depends entirely on the quality of the equipment and the skill of the operator.
Most budget machines won’t yield great results, as they tend to heat a basin of water and then siphon it off for whatever function you opened up. The pressure can be inconsistently all over the place, meaning your espresso pulls won’t be cafe grade. Likely far from it.
It requires some finesse and expertise to do well; microfoam in the milk is difficult to get down, and I still don’t really know all the mechanics behind pulling a “God Shot” – another term for a “perfect” espresso shot.
They take up plenty of space, the decent ones are in the range of thousands of dollars, and they require regular maintenance.
All that being said, when the coffee is good, it’s very good.
If you can afford a decent-or-better one, and you have the desire to experiment and study the craft, you may want to consider one. But is the price tag worth the gains? That’s up to you. You may be ahead to support a quality local cafe.
Strengths: Best/only way to make quality espresso shots; capable of making silky microfoam; a wonder of coffee science/engineering. Lots of customization and variability for those citizen scientists among us. They can also be a nice addition to the decor.
Weaknesses: Expensive, massive, loud, requires regular maintenance, and expertise. If you want to deep dive into coffee, this would be a good venue – but otherwise, stay away.
Pitfalls: Not maintaining it well enough, not cleaning it well enough, not using the good water (hard, distilled, etc.), not purging the lines between shots or after steaming. There are plenty of dangers, as they are finely crafted machines. In general, don’t buy one unless you are committed to coffee and want to drop around a grand or more.
How does brewing work?
As covered in the “Beans” section, grind level determines how long it will take to extract the good stuff from the beans. If non-uniform, it will extract at different rates and either pull too much or too little from the beans.
This affects flavor because too little extraction means it will often taste sour and thin. Extract too much and you’ll get the right consistency, but it’ll have some of the more acrid, bitter flavors.
For more detail, consult the Beans section (above).
The ideal temperature for the coffee slurry (when the coffee grounds are already in the water) is 195º-205º (90.5ºC-96ºC) – which is just shy of boiling. Good machines should allow the target temperature to be programmed in.
However, in this video, they demonstrate that if you take boiling water straight from your kettle (212ºF/100ºC), just the simple act of transferring the liquid into a preheated french press caused the liquid to fall within the upper range of the ideal brewing temperature. This was without any coffee added.
With the addition of coffee, they found that it was similar, but still dropped an extra degree (F). They also checked with a non-preheated french press, and it dropped yet another 5ºF.
In short, if you go straight from boiling into your desired brewing method, the act of pouring and the addition of the room temperature coffee will bring it to the desired brewing temperature for the coffee-water slurry.
In other words, no need to be overly cautious about temperature. Make it hot, preheat your container with a rinse, then go to town.
How does temperature affect flavor?
Well, when it comes to chemical reactions, dissolution included, heat tends to make processes go faster. Too cold, and you won’t get all that you’re looking for in a standard time frame. Too hot and it will denature proteins and destroy compounds that fill out the flavor. And yes, apparently that extra 17º-7ºF (9.5-4ºC) makes a difference to the more sensitive compounds. If you don’t buy that, then let’s go with “it’ll over-extract if you go too hot”. This should only be a problem if you’re using a boiling brewing method, like Turkish coffee or Cowboy coffee (#4 and #21, respectively, in this post).
Cold just takes a long time, and might not grab some of the solutes that need higher temperatures, which might explain why cold brew tends to be sweeter, even though it’s been brewing for longer than 12 hours.
Go straight from boiling into a preheated brewing container, whatever it may be. Just rinse the brewing method with hot water for 30 seconds, swishing it around, then proceed with the brewing. Don’t fixate too much, just control it as best you can; the other variables are probably more important.
Well, the fun thing (and I mean this sarcastically) is that coffee ratios are most often talked about in terms of weight and not volume. Yes, it’s more precise, and yes, you’ll get better results.
But it’s annoying because… well, many of us don’t have food scales, and many of us would rather not have to measure precisely before our first cup of coffee. Regardless, it’s the best approach.
It’s an important factor when it comes to flavor because too little means a thin coffee that’s almost akin to wasting those beans. Too much and the coffee probably can’t even absorb that much, again leading to waste. Or the flavor may end up too intense.
A general rule I’ve come across is of a coffee:water ratio of 1:17 (so 20g coffee would need 340g water)
Here’s a chart to experiment with brew strength. It’s intended for french presses, but it’s a general guide for strength.
|Brew Strength||12oz / 3 cup (French press unit)||34oz / 8 cups (French press unit)|
|Mild||Coffee: 3 Tbsp (18g)|
Water: 300mL / 10oz
|Coffee: 9Tbsp (55g)|
Water: 900mL / 30oz
|Medium||Coffee: 4 Tbsp (23g)|
Water: 300mL / 10oz
|Coffee: 11 Tbsp (68g)|
Water: 900mL / 30oz
|Strong||Coffee: 5 Tbsp (30g)|
Water: 300mL / 10oz
|Coffee: 15 Tbsp / 89g|
Water: 900mL / 30oz
Degassing is a stage just after roasting where the beans let off a significant amount of CO2. This is partially why the bags have those special holes on the front – they are a one-way valve that allows the gas to escape.
Gas is still being emitted for up to 14 days after roasting. If you recall from previous sections in this article, the middle of the 2nd week is the best compromise between a mature flavor and freshness, which likely has a connection to the gas.
When brewing with freshly-roasted, freshly-ground, fresh-as-fresh-can-be beans, you’re going to get something called “bloom” in the brewing. The “bloom” is when a lot of bubbles escape, giving the appearance of pop rocks, minus the sound. This is because grinding the beans increases surface area and increases the rate of CO2 escaping.
Let it bloom
You don’t want the CO2 to be in there for two reasons:
- CO2 has a sour flavor, which is not something we generally want in coffee. Don’t get me wrong; I believe sour has its place, such as with the lemon coffee I’ve seen around Asia. Just probably not something you want every time.
- The constant bubbling of the gas will limit the amount of exposure to the water, meaning that it could lead to an imbalanced exposure. This is the same issue as when using non-uniform grinds.
No special equipment, you just need to add enough water for 30 seconds and let it bubble for a bit. Take the opportunity to re-boil your water if you like, but that doesn’t even seem necessary.
Straight from boiling, wet the grounds, wait 30 seconds for the bubbling to die down, then add the rest of your water.
No muss, no fuss.
I think the best way to approach this is with another chart. Yes, another chart.
There are just too many methods, and each requires a different amount of time to play within. They are all affected by your grind level, so I’ll also include the suggested coarseness and the time you should expect for each example. This is not meant to be exhaustive.
|Coffee Type||Grind Level||Time|
|Drip Coffee / Flat-bottom filters||Coarse to Medium Grind||N/A|
|Drip Coffee (conical filters)||Fine Grind||N/A|
|Pour Over (Chemex, Hario V60) (Cone shape filters)||Medium to Medium-fine Grind||N/A|
|French Press / Immersion Methods||Coarse Grind||3-4min|
|Aeropress (standard)||Fine||<1 Min|
|Aeropress (Inverted)||Medium to Medium-Fine Grind||2-3+ min (coarser for longer)|
|Moka Pot||Fine to Extra Fine Grind||Until water has evaporated/stopped flowing|
|Espresso||Fine to Extra Fine Grind||20-30sec|
|Turkish Coffee / Cezve / Ibik||Extra Fine to Powder||Grind – 3-4 min|
|Boiling methods (e.g., Cowboy coffee)||Extra Coarse||Bring to boil, add coffee, wait 3-5 minutes |
(very few sources with precise time)
|Cold Brew||Extra Coarse||12-24 hours|
What determines strength (flavor and caffeine)
Pretty much all the factors discussed will affect the strength of coffee. But which one do we mean: strength of caffeine or flavor?
Here’s how each of the most-relevant factors contribute.
- Grind: The coarser the grind, the longer it will take to extract what you want from the bean, including caffeine. As well, inconsistent grinds will mean that you’ll get all the caffeine from some portion, and a fraction from other bits. Again, it’s always important to have a consistent size of granule when grinding.
- Bean Variety (robusta or arabica or blend): robusta has roughly twice as much caffeine as arabica.
- Instant or Regular: Instant tends to have less caffeine, but it also has more flexibility because you can always add more until you have a coffee sludge. That being said, a standard cup of instant has less caffeine than an average cup of coffee.
- Time – If you under-extract, you’ll end up with less caffeine. This means taking too little time for the level coarseness will result in less caffeine.
- Temperature – The colder the water, the longer it’ll take to pull things out of the beans.
- Roast: I’m throwing this in here just because it’s such a pervasive half-truth. People believe that lighter roasts have more caffeine, but it doesn’t seem to be a significant difference. The fine folks at Kicking Horse Coffee show that darker roasts lose more mass because they lose more water during the roasting process – not caffeine. If you measure by scoops, light roast will have marginally more. If by weight, then dark roast will have marginally more. You will not notice.
- Roast: I go into more detail in this post.
- Light Roast: Mild Sweetness, Full Aroma, Full Body
- Medium Roast: Mild Sweetness, Very Full Aroma, Strong Body
- Dark Roast: Full Sweetness, Full Aroma, Medium Body
- Bean Variety: Arabica is the more common, palatable variety. Robusta has an earthy, woody flavor.
- Grind: This is mainly to do with consistency – again. I know I’m bludgeoning this home, but inconsistent grinds suck. They will affect the flavor negatively.
- Time: This is more to do with your method and extraction rates. If it’s uniform consistency, then you’ll have to do some experimentation and check the time necessary for your method, but too much or too little time will affect outcomes.
- Temperature: Too hot, and it’ll break down some of the more desirable flavors (unlikely). Too cold, and you’ll probably fall into the “under-extracted” territory.
A comprehensive TL;DR for this post is impossible, but I will recap by saying some of the basics:
- Distilled = Bad
- You want some minerals in it and buffer capacity (bicarbonates)
- Brewing Temperature
- 195º-205º (90.5ºC-96ºC)
- Whatever you do, keep it consistent
- Actively avoid blade grinders; opt for burr or disc grinders
- Whatever you use, clean it regularly; do a cursory amount of research
- Look up the suggested grind levels and their associated brew times
- Robusta has twice the caffeine of arabica
- Instant has less caffeine than regular
- Decaf still has a small amount (3% or less in the USA; 0.1% or less in the EU); the process is safe
- The “bloom” is when the grinds let off CO2 for the first thirty seconds of brewing before adding the rest of your brewing water. Add enough to wet the grinds, then wait for it to slow bubbling.
And that’s all I have to say on this area of the basics of coffee. Hopefully, you learned a lot and found this interesting!