With the engaging popularity of various brewing methods, preparing coffee seems easy as you only need basic ingredients; ground coffee and water. However, it is not that simple because brewing the perfect coffee sometimes requires a lot of work.
In the world of coffee brewing, there are many factors you need to understand. One of them is controlling your brew using proper extraction.
The start of learning and mastering your coffee is by having a careful understanding of coffee extraction basics. Extraction is indeed the most important aspect of coffee brewing. It can either make or break the flavor of your coffee. But if you give the effort to understand what it is and how to manipulate it entirely, you can brew the best coffee you possibly can.
Let’s take a look at this article and further explore extraction. We included the Coffee Brewing Control Chart to determine the relationship between percent extraction and total dissolved solids at a given brewing ratio.
What is Coffee Extraction?
Coffee extraction is a process of extracting soluble compounds from ground coffee. It is simply referred to as brewing coffee since it involves a combination of ground coffee, water, and time.
But some science goes behind this concept as many reactions happen during this process. In coffee brewing, extraction is needed to dissolve those beans’ different organic complex compounds that are developed from roasting.
So, what happens is that the solid components of ground coffee are transformed into liquid. Since the flavors are easily dissolved with hot water, this produces a coffee extract. This extract is composed of water-soluble compounds that directly influence the taste and aroma of the coffee.
[embedyt] https://www.youtube.com/watch?v=lKzzqTlo_BA[/embedyt]Extracting the Chemical Compounds
While professionals tend to approach extraction as chemical analysis, you can start by just having relevant information and understanding its principle.
There are a lot of helpful descriptive guides that you can use to evaluate your coffee. Wherein the body, aroma, acidity, flavor, and aftertaste are the categories used to define a good coffee. But in extraction, your extracted coffee is expected to contain these essential compounds.
Acids – Acidity is a vibrant sensation that brightens the taste of your coffee. You need to extract the right amount of it to avoid a dull and lifeless brew. Acidity is an important compound that lifts and completes the full potential of your coffee.
Caffeine – Caffeine is often recognized as a bitter-tasting stimulant. You also need to extract this compound to be mixed with other ingredients and balance the coffee flavor. Besides contributing to the overall taste, caffeine is the suitable compound you need to jump-start your day.
Lipids – The lipid content of a brewed coffee plays an important role when perceiving mouthfeel. Coffee and tea are unique complex compounds that make your mouth perceive them weirdly. Lipids are a typical component found in coffee oils, which is a function of the composition of the bean and the conditions of extraction.
Sugars – A well-balanced extraction tends to results in a sweeter and more flavorful brew. The sweetness, viscosity of your coffee is also an essential factor in improving extraction. It is introduced to balance the unpleasant elements like bitterness and astringency.
Since the coffee has the body, acidity, flavor, and aroma derived from hundreds of extracted compounds from the roasted beans, it’s essential to have relevant information on how to manipulate the variables that affect extraction.
The Coffee Brewing Control Chart
Coffee professionals and experts widely use the Brewing Control Chart to evaluate their brews. You can also use its graph to understand the concept of coffee brewing clearly.
For example, what happens if the TDS/Total Dissolved Solids and PE/Percent Extraction are not within the ideal region? By looking at the graph, you already have a baseline for the result you can expect. You just have to taste the final product to verify the calibration of the coffee.
It’s confusing at first, but it’s worth it if you will put the effort to study and understand it. In the end, you can control your brew and have a good cup of coffee.
The control chart below can be boiled down to basic measurements. Ideally, extraction is conveyed by a lot of variables. The brew ratio, extraction percentage, and the ideal level of extraction are the important measurements that determine the extraction.
Brew Ratio
A coffee to water ratio that creates a coffee that suits your taste preference. Your recipe should have the correct balance between the amount (by weight) of grounds and the volume of water poured over that ground coffee.
Strength
It is the aspect of explaining the soluble concentration of your brew. However, remember that strong coffee isn’t always the result of high extraction, neither the result of a high concentration of caffeine.
In this case, strength is technically used to demonstrate the concentration of the extracted soluble compounds within your brew. Looking at the chart below, the standard optimum percentage of soluble concentration ranges from 1.2%-1.45%.
Extraction Percentage
The percentage of the dissolved solid particles out of ground coffee tends to be around 18–22%. This is the ideal extraction yield %, according to the Coffee Brewing Institute. Under and beyond these values are usually seen as under-extracted and over-extracted.
Total Dissolved Solids (TDS)
TDS is a measurement referring to the calculated number of coffee solids that have been extracted into the water. Using a refractometer, you can measure the TDS in your brew and be interpreted in PPM (parts per million).
On the other hand, the TDS% is the coffee solids’ concentration measured in percentage. It indicates the strength of your coffee, ranging from 1-12%, whereas the higher the TDS percentage, the stronger the coffee is.
The strength (TDS) of the brewed coffee is plotted on the vertical axis. The extraction percentage is on the horizontal axis. And finally, the brew ratio represents those red diagonal lines. The ideal goal is to get into the ‘Optimum Balance’ area.
While the flavor wheel features dozens of flavor attributes, this coffee brewing control chart only points into two details, bitter and under-developed.
Under-developed Area– Providing flavors interpreted as sour or grassy caused by low extraction. That is because the needed coffee flavor has not been extracted.
Bitter Area – Introducing unpleasant and unfavorable elements due to high extraction. The coffee has been extracted beyond the recommended time, making it more bitter.
Optimal Balance Area – It is your ideal brew, where it has the right balance between sweetness, bitterness, and acidity.
Note: Although you may find it relevant in its time, according to SCA, this classic chart lacks applicability in this modern brewing era. There is a constant shift in consumer preference, new brewing techniques, and increased demand for unique coffee. In this case, it’s challenging to develop this chart better. Luckily, current research is underway to work on updating and expanding the classic Coffee Brewing Chart.
How to Calculate Extraction
Extraction is usually conveyed by extraction (soluble yield) percentage. Supposed you want to know how many percent of coffee (soluble) particles have been dissolved in the water, you can start by experimenting with your dosage.
Extraction yield% is computed by dividing the TDS (g) by the Dose of Ground Coffee, then multiplying by 100%.
Extraction yield% = TDS (g) /Dose (g) x 100%.
Let’s take an example. Let’s say from your dose of 20 grams. A refractometer is used to measure the amount of Total Dissolved Solids (TDS) in your brew. You ended up with a total of 4 grams of dissolved solids in your cup from the refractometer reading.
Using the above equation, you can calculate the extraction yield, which is 20%. (4g / 20g x 100% = 20%).
You can also use the formula provided by the BaristaInstitute to compute for extraction rate or extraction yield. In this case, as mentioned, the TDS % is usually the range for different types of coffees from 1-12 %.
Let’s say you ended up with a total of 40grams of brewed coffee, having a dose of 20 grams. You want to know the extraction yield% when the refractometer measures a 10% TDS. By using the formula, the extraction is 20%. (Extraction Yield% = 40g x 10% / 20g = 20%)
But what if you want to decide on the amount of ground coffee based on the given chart above? You can use this formula derived from the above equations.
[Ground coffee (g) = 1000 (TDS) / Extraction + 2(TDS)].
If you need to brew a coffee within the Optimum Balance area, you may want to have a TDS% of at least 1.25 and extraction% of 20. By doing the math and using the chart as your guide, you can easily determine the ideal dosage before you start brewing, which is approximately 55.5g. [Ground coffee = 1000 x 1.25 / (20 + (2(1.25))].
However, in reality, these numbers are just your guide. Aiming for a particular value doesn’t guarantee the perfect coffee. Since not all coffees are the same, you can still have a balanced extraction if you focus on the variables that get the highest or ideal percentage extraction.
How does Extraction Affect Coffee Taste?
You need to extract the flavors, acids, oils, and other elements from the grounds. However, these compounds have different mouthfeels and are not all dissolved at the same rate.
Some flavors, such as the acidic and fruity notes, are pulled out first because water can dissolve quickly. The oils and sugars follow it as they take a little more time to come out. And then, finally, the bitterness is extracted last because it takes a longer time to dissolve. Once you understand this process, it can lead to getting a balanced extraction.
Controlling the extraction allows you to create a coffee that suits your taste preference. However, while its concept is always straightforward, you may still find it more challenging to execute. So, you need to understand the concept of extraction as it is the most important aspect of brewing coffee.
Balanced Extraction
This level of extraction happens if you pay attention to the critical variables that contribute to perfect extraction. Balancing countless variables allows you to achieve a well extracted, delicious coffee. Remember that the sugar levels, acidity, and bitterness of the brewed coffee are also correlated with the extraction percentages, and balancing these compounds requires significant work.
While higher extraction percentages don’t really mean a stronger brew, it positively responds to higher sugar levels in coffee. But in the end, understanding these aspects help you brew better coffee.
Clarity and Transparency – The clarity in your cup tells you what your coffee really tastes like. It may depend on many variables, such as the brewing method or type of bean, in achieving clarity and transparency. But overall, a balanced extraction also gets the flavor you want from coffee.
Sweetness – You know you did a good job when you brewed an excellent and smooth coffee with a fruity and floral flavor that dominates bitterness. That is because of the extracted oils and lipids that provide a decent cup of coffee, which leaves you wanting more another sip.
Acidity – A balanced extraction tends to deliver a complex overall flavor with the right mixture of bitterness, sweetness, and acidity. While acidity is one of the most important elements in coffee, too many acids can negatively affect your coffee experience. It can be either good or bad, light or heavy on your tummy, depending on your tolerance. But luckily, proper extraction is one of the ways to brew less acidic coffees.
Over-Extraction
Over-extraction happens when too many soluble materials are extracted out of the ground coffee. This gives you an awful coffee taste because that unpleasant bitterness and astringency overpower the sweetness and acidity of your coffee.
This level of extraction occurs because your grounds are too fine and your water is very hot. The beans that are ground into an extremely fine powder have more surface area for water to extract the flavor faster.
Other variables contribute to it, such as the extraction time, pressure (in espresso), grind size, brewing technique, etc. But luckily, we can extract the right amount of flavor to make an enjoyable cup possible by controlling these mentioned variables.
Signs Your Coffee is Over-Extracted
According to the baristahustle, three things distinctly indicate over-extraction. If your brew is bitter, drying, and hollow, then you’ve probably over-extracted your coffee.
Bitterness – Over-extraction results in bitter coffee. While the bitterness in your brew comes from caffeine, most of the time, it is the result of improper extraction. If your cup of joe has a dominant taste of bitterness, it is because you extracted a bunch of bitter chemicals from your grounds during the brewing process.
That’s not the only aspect that contributes to your coffee’s flavor profile. A darker roast, for example, also influences the perception of bitterness. If you want to know more about it, we have written an article on the Reasons why your Coffee Tastes Bitter.
Dry Mouthfeel – Dryness in your coffee is a sign of over-extraction. It is described as an intense sensation that makes your mouth feel dry. It’s like eating raw fruit or something similar, making you feel like all the moisture is sucked up throughout your throat.
This sensation lingering in your mouth is called “astringency.” It is caused by chemicals responsible for dryness in coffee. It tastes the same as the aftertaste of unsweetened black tea. The best way to experience it is to grind and brew green coffee.
Empty Flavor – Over-extraction doesn’t only provide overpowering and dominant taste. Too many complex compounds can eliminate other flavors and make your coffee just tastes empty and lifeless at all.
For example, caffeine is a tiny element of your coffee, but it is the most important compound determining the coffee’s unique identity. Over-extracting a wide range of elements can weaken the structures of other compounds, resulting in a dull and unexciting coffee.
The fact that coffee has thousands of complex compounds, these compounds have different chemical bonds and effects. And it’s still difficult to understand their relation and reaction to each other.
An overdosed flavor reacts with other ingredients and produces a new perception of taste. You can’t obtain the perfect balance and consistency and probably can’t recognize the right recipe if there are too many flavors in your brew’s composition.
Under-Extraction
On the other hand, under-extraction occurs when you haven’t extracted enough soluble compounds out of the grounds. Ground coffee has many flavors to offer, but leaving those essentials behind those beans makes an unbalance and undesirable coffee flavors.
This level of extraction happens if your grounds are too coarse. You can’t easily extract out the needed flavor from your coffee. The too coarse grounds also affect how quickly you can make yourself a cup of coffee as this kind of grind consistency takes time to brew. The water can’t dissolve enough stuff from the grounds.
Many variables affect under-extraction. Luckily there are some indicators of under-extraction you can use as a guide.
Watery – While the lack of flavor is usually caused by various factors such as water temperature, coffee to water ratio, etc., weak coffee is primarily the result of under-extraction. Under extracting the flavors from the grounds gives a lifeless and tasteless coffee. You can’t enjoy drinking your favorite drink if it’s incomplete at all. Based on the discussion above, it’s from an under-developed area.
Sourness – The sweetness and slight bitterness are the things that you need in your cup of joe. But if you’re not paying attention to proper extraction, your coffee will have a sour taste instead. Sourness is not the ideal flavor you want in your brew. It is usually defined by the beans’ freshness, but you can also get it from under-extraction.
Saltiness – You can’t literally taste like you poured a bunch of salt into your cup, and there should be factors contributing to this aspect to make sense. However, under-extraction can still provide a salty flavor under some circumstances. If you can get a sour coffee, then it’s possible to have a salty brew as well. Acids and salts tend to be dissolved faster than sugar, and this salty flavor is sometimes derived from the sourness of your coffee.
Conclusion
There you have it! In the end, you have a rough guide and a baseline you can use to describe how good your coffee is. It’s easy to match your brewing technique and delicious coffee simply by using the principle of coffee extraction and the brewing control chart above.
However, we have only discussed the good and the bad extraction. Remember that many variables affecting it, such as extraction time, temperature, grind size, and so on. Give the effort to explore and experiment with them by adjusting one factor to another. After all, understanding extraction and other variables contributing to it allow you to brew better coffee.
Like this Article? You Might Want to Read: 10 Brewing Mistakes that could Potentially Ruin your Coffee