- Coffee flavors are composed of the taste, the aroma and the texture.
- The design of the brewing equipment, the brewing method and the type and porosity of the filter have an impact on coffee flavor.
- If you know the main cues (e.g., filter porosity, shape of brewer, etc.), you will be able to understand any brewing method, even if you have not tried it yet.
...if you have time, dive deep into the full article
What is the best way to make coffee?
This is one of the frequently asked questions when I am talking with people about coffee and the differences of how we brew it, for instance, in Italy or over here in Costa Rica.
My simple reply is: “It really depends on what you want!”
Rather than asking for the holy grail of brewing a good cup of coffee, the question should rather be:
What is the best way (or the best brewing method) to make coffee with, so that by using it, it will give you the flavor profile that you personally want?
Let’s imagine you have only one type of coffee available. By using different brewing methods you can alter the flavor profile of this same coffee. I could make now a coffee brewing method comparison and explain for each of them what flavor profile they provide in the cup. But I prefer to take another approach with you.
In order to understand how a specific brewing method affects coffee flavor, first, it’s important to understand the composition of coffee flavor and how this interacts with the brewing tool. In other words: what parts of the brewing tool affect the flavor-contributing compounds of coffee?
Where does the flavor of coffee really come from?
First off, flavor always describes the overall perception of a beverage or a food, which includes the tastes, the aromas and the texture (also called body or mouthfeel).
In coffee, tastes, aromas and body come from different compounds and only their interaction contributes to what we call coffee flavor. Let’s take a closer look at these three components:
The basic tastes in coffee such as sweetness, acidity, bitterness or saltiness come from solids, which are present in the coffee grinds or particles. As soon as water comes into play, these solids are dissolved from the coffee grounds and “transported” to the final coffee beverage, usually strained through a filter before.
The amount of and what specific taste-contributing compounds are dissolved from the coffee grinds depend on a variety of factors such as the roasting and the actual brewing process, among other things.
Aromas are much more complex and it is said that coffee has more aroma-contributing compounds than wine. A certain degree of aromatic compounds is trapped in the raw (green) coffee bean at a very low level. Indeed, when you take some green coffee beans in your hands and smell them, the aroma is quite uniform.
The real transformation comes as soon as the beans enter the roasting drum. Different chemical reactions occurring inside the beans cause to create a myriad of aromas. Depending on the roasting degree, aromas can vary in their intensity.
The intensity of aromas in a cup of coffee really depends on the roast and the freshness of the beans as well as the clarity of the cup (I will come to this in a few moments).
Especially the freshness plays an important role as coffee aromas are usually very volatile.
Body doesn’t refer to a taste, but to a feeling you will have in your mouth. Body is the texture of coffee and is composed of solids which are not soluble in water. There are mainly two compounds which are not soluble in water and give coffee its texture:
- Organic matter (very tiny coffee particles as a result of the grinding)
- Coffee oils
- Melanoidins (contributes to the brown color of coffee)
The tiny particles are called fines and are created when coffee is ground. You can see them, for instance, when you prepare a French press or a Moka pot coffee. At the bottom of the cup, you usually see a fine layer of coffee particles.
Coffee oils also contribute to the texture of coffee but in a more smooth way. While fines may give you quite a rough feeling in your palate, oils are like eating a spoon of honey, just smooth. Oils are easily recognizable as they are floating on the surface of coffee as a shiny layer. Just imagine a cup of water with some oil drops in it.
Disclaimer: I’ve often read that shiny coffee beans (which means that oil is on their surface) are a good thing. But the opposite is the case. When coffee beans have oil drops on their surface, these oils can start to oxidize providing rancid aromas and tainting the beans and thus affecting the overall coffee flavor negatively. I know that we usually like shiny things, but in coffee, this is not what we are looking for ;)
Now, what about the brewing method?
Now that you know which compounds contribute to the flavor profile of a coffee, we should talk about the brewing method/tool. What the brewing tool really does is to take these compounds and put them in a relation to each other.
That means that there are some brewing tools which contribute to a more aromatic cup, while there are others which contribute to a bold cup with a lot of texture (body or mouthfeel) and, of course, everything in between.
The interaction between the flavor-contributing compounds and the brewing tool is mainly influenced by:
- The design of the brewing tool
- The brewing methodology and the filter porosity (Drip, Immersion, espresso machine, Vac Pot, a combination of them)
The design of the brewing tool
Each brewing tool has a specific design and a way coffee is brewed. Depending on the design, the barista (you) has to adapt the brewing process and technique in order to get a good cup of coffee. Before choosing a brewing tool, look for the following things:
- Does the brewing tool have a direct heat source or not?
- What kind of shape does the brewing tool have?
Does the brewing tool have a direct heat source?
Examples: Moka/Stove Top Pot, Vac Pot
A direct heat source such as a stove or a gas-powered flame can be a good and a bad thing. It all comes down whether you can control it properly and thus control the temperature. Keep in mind that the temperature is fundamental for the extraction of flavor-contributing compounds.
Universally recommended is a brewing temperature range between 92 and 96 degrees Celsius. If you can control the heat source to remain within this range, excellent! If not, no worries, but you should be prepared for a coffee that could be over-extracted and thus has more bitter notes than it should.
An example is the famous Moka Pot, a tool I grew up with in my Italian family. As it is difficult to control the brewing temperature, it can result in an over-extracted coffee. Another example is the Vac Pot. It has a direct heat source, but due to its open design, you can use a thermometer to control directly the temperature of the brewed coffee particles and thus adjust the flame output accordingly.
What kind of shape does the brewing tool have?
That is a rather tricky question to answer because every brewing tool is unique and therefore contributes to the versatility of coffee preparation. In my opinion, the most important factor to understand as a barista is how the shape of the tool affects the flow of water through the coffee bed and thus the evenness of extraction.
As a consequence, you might look for changing some brewing parameters in order to improve your brew.
Good examples are drip brewers. While there are drip brewers with a perfect V shape, there are others which are also cone-shaped but come with a flat bottom. In both cases, the flow rate of water will be different and therefore the barista has to adjust some brewing parameters accordingly in order to get a good brew.
What is the brewing methodology to extract the coffee and the porosity of the filter?
Although, I have listed these two factors separately, in the explanation it is important to bring them together because they certainly interact with each other and are the most important factors which impact the flavor profile of the cup regarding the brewing tool.
In Everything but Espresso – Professional Coffee Brewing Techniques Scott Rao explains that the brewing methodology determines how many insoluble, (body-contributing compounds - fines and oils) are “trapped” in the coffee bed and thus how “clear” a coffee is.
Here we come back to what I have explained to you in the above. By choosing a determined tool you basically are choosing the relation between soluble and insoluble compounds and thus how clear you want your drink to be.
Rao points out that immersion brews like French Press or AeroPress release most of the insoluble compounds to the cup as they have a direct contact with the filter and pass through the mostly very porous filter.
On the other hand, drip brewers like Chemex or V60 trap a good amount of these compounds in the bed, providing an average mouthfeel to the drinker, while steep and release systems (Vac Pot, Clever Drip) can give you a relatively clean cup.
But this is only one side of the medal because the porosity of the filter has to be taken into account, as well. It is the most important factor to determine how clean a cup is or not.
For instance, most metal filter comes with relatively large holes and therefore allow coffee particles (fines) to pass more easily. Whereas a fine-meshed paper filter commonly used in a Chemex will result in most of the insoluble parts being trapped in the coffee bed. The consequence is a clear cup with a tea-like texture.
Let’s wrap this up
You have learned in this post where the flavor-contributing compounds come from and how they interact with the brewing tool. Rather than explaining each tool one by one, I preferred to explain the common cues so that you are able to have an idea of what to expect from a tool even if you don’t know the tool itself.
It is important to remark that the brewing tool is only one of a variety of factors which impact the flavor of coffee and that, depending on the tool, the barista has to decide which brewing technique to adopt and whether to change other parameters in order to get a good cup. Furthermore, the quality of the roast is paramount especially for the solubility of taste-contributing compounds.
As Rao suggests, the main issue is how clear or not your final cup will be. That is not a matter of what is best or not, but what you or your customer like most.
So what is the best way to make coffee for you?
Ask yourself what you enjoy and choose the tool(s) accordingly.
If you reached the end of this post, I’m really happy and want to thank you for that. I appreciate any comment about this article or recommendations to improve it. Or if you’ve missed something, just write me.
Stay caffeinated ;)
Shelton, C. (12 de Mayo 2016 ).Coffee Science: What Affects the Flavor of Coffee? [Blog] Perfect Daily Grind. Available at: https://www.perfectdailygrind.com/2016/05/coffee-science-affects-flavour-coffee/ (Accessed on 2017, June 10)
Rao, S. (2010). Everything but Espresso - Professional Coffee Brewing Technique. Canada.
Title picture by Nathan Dumlao on Unsplash
Corrected & Revised by Andrea Letzner