Coffee – Origin and Varieties

When going to the store to buy coffee, many people face the dilemma of what kind of coffee they should buy. They are exposed to numerous coffees, such as Vietnamese, Ethiopian, Java – Indonesia, or Brazilian, and the selection of different roast levels. Sometimes, we buy one based on marketing and end up disappointed with the final result.

Maybe looking at coffee and answering a few questions about it and what happens during brewing will help us make more informed decisions.

What is Coffee

The berries are harvested from Coffee plant species that can reach heights of up to 9 meters and have a lifespan of up to 100 years. However, the actual production period is between 5 and 20 years.

The fruits of the coffee shrub are known as coffee cherries, and each cherry generally contains two coffee seeds or beans. The beans look like real cherry pits, and only about 5% of the cherries have one seed, called peaberries. The fruit is small, like an olive, and green turns red during ripening.

There are about 50 species of coffee beans, but only two of them are the main ones, Coffea arabica and C. Canephora, and they supply almost all of the world’s consumption.

Arabica is wider spread than Robusta (the main variety of C. canephora) and has a milder and more aromatic aroma. At the same time, it needs specific climate conditions to grow and extra care. The ideal conditions and some of the differences between the coffee varieties are as follows.

History of Coffee

Coffee origins trace back centuries to the region of the Ethiopian plateau. As the legend goes, the goat herder Kaldi first discovered the potential of these beans. After eating the berries from a particular tree, he noticed that his goats became so energetic that they did not want to sleep at night.
Kaldi told the abbot of the local monastery about his observations, and he decided to make a drink with the berries and found that it kept him late in the night. The abbot shared his experience with the other monks at the monastery; they also tried it, and coffee cultivation and trade began.
By the 15th century, coffee was already famous in South Arabia, and about one hundred years later, coffee was already known in Persia, the Middle East, and Turkey. In that part of the world, coffee houses became critical social centers, places for discussion, and social gatherings.

Coffee expansion soon found its place in Europe, though it was initially considered suspicious and declared the “bitter invention of the Satan” – Venice, 1615. Even the pope, Pope Clement VIII, had to express his opinion about the “devil’s liquid.” After he tried and liked it, he declared that it tasted so good that it couldn’t be Satan’s invention, so he gave the coffee papal’s approval.

Bu mid-17th-century coffee houses started popping up in Central and Western Europe, becoming part of everyday life.
Coffee’s popularity continued to spread; the Dutch were persistent in their cultivation efforts, initially in India and later in Indonesia, known as the island of Java.

The New World

Around that time, coffee was making its way to the New World. By the mid-17th century, coffee was already in New Amsterdam – New York, but it did not become popular until the late 1700s, after the revolt against the high tea tax imposed by King George III.

Gabriel de Clieu, in the early 17th century, brought the seeds to Martinique from France, whereby at the end of the century, they already had close to 20 million trees, spreading around the Caribbean and South America.

Another story says that the governor Maranhão e Grão-Pará in northeastern Brasil sent Francisco de Mello Palheta to settle a dispute between French Guiana and Dutch Guiana. The real reason was to obtain coffee seeds from French Guiana, and thanks to his good looks, he did. The governor of French Guiana had already refused his request to get some sources. Still, his wife was charmed by senior Palheta, and she could sneak some seeds in a large bouquet, and the Basilian billion-dollar coffee industry was born.
By the end of the 18th century, coffee had become one of the world’s most profitable export crops.

Bean Belt

The coffee Bean Belt is a particular geographic region with a suitable climate for growing coffee, and it is known as the Bean Belt region.
In general, the decision to produce Arabica or Robusta is determined by the coffee trees’ latitude. Within the Bean belt, the coffee produced in different areas has a distinctive flavour profile particular to that region, which makes it more exciting to find the perfect brew.

These days, the demand for coffee is comparable with the oil demand market, and coffee is currently the world’s top ten most sought-after commodity.

Can you imagine a world without coffee?

How coffee beans become coffee

After coffee cherries are picked up and bought at the processing facilities, they undergo a few different processing steps before the coffee is ready to be shipped.

Extraction process

The two main extraction processes produce different flavour profiles.

The washed method involves washing fruits with water and removing everything except the beans. After washing, the beans dry for about 30-40 days. The resulting taste is a pure bean with a lighter, more tea-like floral aroma.

Natural method – There is not much human interaction involved in this process.

The cherries are left outside for 10-30 days, and during that time, they slowly start to decay. That’s a normal process, and what is happening is that the fruits are undergoing fermentation – a bacterial process that influences the taste of the beans.
The next step is to remove the skin and the pulp from the beans. That step is similar to the washing process, but the beans have additional flavours, such as sweetness and creaminess, caused by the fermentation.

During the natural fermentation, the producers control fermentation development using open tanks, different vessels, and techniques to contain the coffee.

If one desires a sweet and less intense cup of coffee, choosing the natural extract method is the way to go based only on the extraction process.

Anaerobic-environment fermentation

There is another fermentation method called anaerobic-environment fermentation, where some producers attempt to control the oxygen level of the process.

The vessels in which the coffee cherries are fermented don’t contain any oxygen. The oxygen is removed at the beginning of the process. The holding tanks have a valve that stops the CO2 from seeping in and releases the increased oxygen level from fermenting.
Some producers use this fermentation type to enhance coffee cherries’ flavour by adding additives like tropical fruit or molasses.
This process is called anaerobic impregnation.
During that fermentation, a naturally fermented coffee-cherry liquid is produced with a high alcohol content, and it can be served as an excellent addition to coffee tasting.

Coffee Origins

Coffee origins are an essential part of the flavour profile. By origins, I mean the trees are grown at what altitude, not just geographic location.

For instance, coffee grown in a low-altitude environment like Indonesia has a high growth rate and lots of oxygen, and the beans will be less dense than those grown at high altitudes. Predominant flavours are – earthy, sweet, low acidity, and have a more bland character.

Coffee grown in high-altitude environments, 4000-6000 feet above sea level, like in Kenya or Ethiopia, doesn’t have access to the same level of CO2 and, therefore, less energy. That lack of oxygen leads to a process called anaerobic respiration. This process causes the formation of lactic acid, which imports more flavours into the coffee—citrus, chocolate, vanilla, spice, nuts, creaminess, and balanced bitterness.

So far, we have covered two components influencing the coffee flavour: fermentation and origin. Based on that, we can choose what type of coffee we would rather have. Let’s say I’d like a light, fruity, and creamy flavour in my coffee; in that case, I will go with beans that went through a natural process and higher elevation.

Roast

The roast is a scale of roasted levels, from light to dark, depending on how the beans are cooked in the oven.

The roasting process allows the cooking of the bean’s natural flavours to be extracted.
Roasting coffee causes the sugars, fats, and starches contained in the bean to emulsify, caramelize, and release. The resulting coffee oil contributes additional flavour to the coffee.
The roasting process starts with lower heat, and gradually, it increases to 390-480Fº, which allows the heat to penetrate the center of the bean slowly.

As the cooking continues, the coffee beans start changing colour and swelling. At some point, a loud cracking noise can be heard; the sugars begin to caramelize, and the coffee is considered roasted, but it is still at level one.

As the cooking continues, the colour darkens, and the sugars caramelize. Usually, during this step, the roasting is stopped before the second crack noise is heard. At this point, we have a dark roast, and if the cooking continues, all the sugars will be caramelized, leading to a very bitter taste.

The next step is called degassing.

The degassing phase is critical, and coffee production should not proceed to the next steps until all of the CO2 has been released. The usual wait time depends on the coffee, which can be from a few hours up to 24 hours for most brands.
If you decide to brew coffee straight from the roaster, you will consume elements that make the coffee seem woody, bitter, and flat.

Roast Levels

Roasting is an integral part of forming the final flavour profile of the coffee beans, as different chemical compounds – flavours are extracted at other times.

Lighter roasts are usually more acidic than darker roasts.
Darker roasts have a fuller flavour but less caffeine than light roasts.
Over-roasted coffee has a smoky, burned flavour, probably not that desirable in the coffee.

Note: Coffees with the same roast might have different flavours from different origins.

Maillard Reaction

Let’s examine the chemical process during roasting. The Maillard reaction is responsible for sugar caramelization and some other chemical reactions.

In this process, the sugars are combined with the amino acids, introducing new flavours, such as caramel and chocolaty aromas.
During the dark roast, the Maillard reaction is more prolonged; therefore, this type of roast will have more savoury tones, but at the same time, we will have less real bean taste.

Generally, we can summarize the roasting process as follows:
At the beginning of the roast, the dominant flavours are that of the bean – floral and acid. We get new flavours with longer roasting, like caramel, fruit, chocolate, and spicy. The more we continue with the roast, the more the coffee taste changes to a bitter and harsh charcoal taste.
Based on the extraction method, origin, and roasting scale, we can decide on the type of coffee we might buy.

If I want coffee that tastes sweet, not too acidic, or bitter, I will use the natural method, high altitude, and medium roast.
If I want a dark cup of coffee, I might choose a washed, low-altitude, dark roast.

Coffee Grinding Options

Deciding on the coarse level of coffee grinding is one essential step toward the expected quality of the final brew. Grinding aims to break the beans and expose them to flavour extraction during brewing.
We increase their surface exposure and extract all the desirable flavours into the water by turning them into smaller particles.

If we look at what is in the cup of coffee, we might be surprised that more than 98% is water.
That’s why finding the right size will significantly determine the quality of the final brew.

Here are some suggestions for finding the right timing, equipment, and coarseness for coffee grinding.
If the ground coffee is too delicate for the brewing method, the final result will taste more bitter. If the coarseness is too large, we may have an under-extracted flavour.

Decide what brewing method you want to use that will help determine the coarseness level. Use a good quality grinder; cheap ones will likely produce uneven grinding particles. Ideally, grind the beans right before brewing. Always keep the grinder clean.

Coffee Grinders

Coffee grinders: If money is not the primary concern when buying a coffee grinder, go for Burr Grinders.
There are two types: Wheel Burr and Conical Burr will grind coffee evenly and not overheat and affect the flavour.

Many people prefer the Conical Burr as it is not messy and less prone to clogging.

Caffeine – The Trickster

Caffeine is a methylxanthine alkaloid that occurs naturally in tea, coffee, nuts, or leaves of several plants native to South America and East Asia.
It is a central nervous system stimulant structurally related to adenosine, with a similar molecular structure.

To understand the importance of their relationship and how caffeine works, let’s first see what adenosine does.
Adenosine is a central nervous system neuromodulator that has specific receptors. When activated, the neural activity slows down, decreases the adrenaline, and makes you feel sleepy.

According to an article on the McGill University website, “caffeine acts as a blocker to the adenosine effects. Activating numerous neural circuits causes increased production of adrenaline, improves the awareness, and gives the body the feeling of “more energy.”

Another independent study, published in Physiology & Behavior, 2017, came to a similar conclusion about the effects of caffeine on our nervous system.

the increased anxiety-like behavior and depleted cognitive functions under stress conditions were improved …

Physiology & Behavior

Caffeine may also positively affect slowing down and protecting cognitive decline. In 2017,  Boukje van Gelder and her colleagues reported the results of a 10-year study on the effects of coffee on 696 men. They found that men who drank coffee had less cognitive decline than those who didn’t. The researchers observed the most significant impact on people who drank three coffees daily compared to those who had fewer or more coffees daily.

In a recent article, Dr. Uma Naidoo, a nutritional psychiatrist and a faculty member at Harvard Medical School, also mentioned a few key ways coffee can support the brain:

• Caffeine increases serotonin and acetylcholine, which may stimulate the brain and help stabilize the blood-brain barrier. 
• The polyphenol micronutrients in coffee may prevent tissue damage by free radicals and brain blood vessel blockage. 
• High concentrations of trigonelline are found in coffee beans, which may also activate antioxidants, thereby protecting brain blood vessels.

According to her, not every coffee substance is helpful. For example, unfiltered coffee contains natural oils called diterpenes, which increase LDL cholesterol levels — potentially resulting in the thickening and hardening of the artery walls in the brain. Choosing dark roast freshly ground coffee may reduce the unwanted chemicals in your brew.

Based on the studies mentioned above, the benefits of caffeine don’t mean we have to drink coffee all day long. Overindulging in caffeine-laden drinks can harm the body, causing increased adrenaline and cortisol levels.

Overexposure to stress hormones, including cortisol (the main stress hormone), can cause trouble within almost all body processes, increasing the risk of weight gain, sleep problems, and anxiety and inhibiting insulin effectiveness, increasing blood sugar (glucose) levels.¹

I guess moderation is vital to everything, so the question is, how many coffees are you supposed to have? There are many variables to be considered, but generally, the recommended amount of coffee is two a day and no more than four. Once in our body, caffeine is absorbed within about 45 minutes after consuming and peaks in the blood anywhere from 15 minutes to 2 hours. That will depend on the person’s caffeine tolerance; some people can drink coffee all day without side effects, but most will feel jitters after the fourth or fifth coffee.

It is also essential to understand that caffeine does not give us extra energy; it fools us and stops the brain from thinking, “I’m sleepy, I’m tired, I need a nap.”

Caffeine Effects

Caffeine levels in certain products

Brew

Finally, we brew some coffee, but what method should I use? What about the water-to-the-c coffee ratio? I want my caffeine. OK, go ahead and have a cup of coffee.
Let’s see if these previous questions make any difference in the final brew.

Bean Chemistry

There are two parts to a roasted bean – solubles and non-solubles.

Non-solubles – give shape structure and are left behind after brewing.

Solubles – all the extractables provide colour, aroma, and flavour.

The percentage of the solubles (colour, texture, flavour) in a cup of coffee depends on the yield and concentration of the brew.

Soluble yield is focused on the type of flavours extracted. For instance, the bitterness is extracted later in the process, and different desirable aromas are pulled at other times within the brewing process. Let’s say we have three coffees brewed for 2-5-10 min. The first might have an underdeveloped- weak flavour, the second – is just right, and the third will have lots of bitterness.

Time is also one crucial factor to consider, among others.

Soluble concentration is about adjusting the amount of coffee needed, hence the required materials.

Time, water, and quantity are necessary not because they create the best coffee, no such thing, but because they can adjust the brew to our liking.

There are other ways to measure these variables; I will briefly mention some. For more detailed information on these parameters, check Martin Lersch’s detailed posting on his blog.

Parameters influencing the final brew

The BR—Brew ratio measures the amount of water to coffee: the weight of the coffee X 16.7 = water needed.

The multiplier can vary between 14 and 17. To determine how much coffee we need for our brew, we divide water volume by 16.7 = coffee.

TDS measures total dissolved solids and solubles in the final product. Typically, there are 1.2-1.5% of total dissolved solids, which means that only 12-15 grams of extracted solids are out of 60 g per 1000 ml.

EE – Extracted yield – calculated from the amount of solids extracted from the coffee grounds.

EEY—Effective extraction yield—measures the effectiveness of the solids extraction in the brew. The choice of brewing method will also affect this.

PSD – particle size distribution is about Grind size. Particles of the ground coffee have different sizes; it is accepted that they should be smaller than 100µm. The exaction occurs on the surface of particles smaller than 100µm, meaning any particles bigger than 100µm are not part of this process and become wasted coffee.

The mineral content of the water can influence the brew as well.

Water temperature – can lead to different flavour profiles. Different temperatures extract various chemical compounds, and the optimal temperature is around 93º-99ºC.

• For instance, if we do cold brew, the final flavour is not so sweet or bitter, as the extraction of the compounds depends on the water temperature.
  

Methods of Brewing

Immersion method

There are different methods of brewing coffee; some require more manual control—Pour-over and Immersion steeping—and others not so much—percolation, vacuum filtration, and pressurized infusion.
Is one better than the other? I’m not sure, but let’s see some of the differences between the manual ones as we have more control over them.

The French press is using the immersion method to brew coffee.

The preferred grind is a coarser coffee ground with a longer brew time. Adjusting the course grind to finer will make the brew fill stronger, and if it is too harsh, change it to a coarser grind.
This method allows coffee and water to stay together for a longer time, around 4-5 minutes, which extracts every soluble from the coffee in the water. It results in an oily brew with a good body and thick texture.

Pour over method

It uses medium-coarse to medium-fine grind.

This method is entirely different. After you place the coffee in the filter and pour the water, the water goes through it immediately, extracting only the available coffee components. The interaction of the coffee and the waters lasts only for short moments instead of more extended time in the full immersion method.
The speed of coffee extraction is faster, but if one is pouring the water too fast, it might extract the flavour too quickly and potentially brew inferior coffee.

Note: A critical step with this method is to wet the beans for 20-30 sec before pouring the water, allowing the coffee beans to degas the trapped CO2.

Another note here is that when we pour water over the coffee, we have to make sure the filter is not clogged and the water doesn’t go over the sides of the filter.
If you are after a pure bean taste, go for Pour-Over. If you’re after a more complex, thicker texture, the Immersion one is probably a better option.

Instant Coffee

Instant coffee is a fast and easy way to have a cup of coffee. In short, it is made from brewed coffee that has had the water removed. To make instant coffee, add some water to hydrate the powder.

• The first “instant coffee,” called coffee compound, was made in Britain in 1771 and had a patent granted by the British government.
• During the Civil War in 1851, cakes” of instant coffee were shared in rations to soldiers.
• David Strang from New Zealand invented and patented instant or soluble coffee in 1890.
• Japanese-American chemist Satori Kato invented the first successful method of creating a stable soluble coffee powder, who exhibited it at the Pan-American Exposition in 1901.

Instant coffee is usually made from Robusta beans. One of the reasons why Robusta is the bean of choice is that it is easier to grow and has a higher caffeine content than the Arabica bean. An essential consideration is the loss of some caffeine while making instant coffee.

The beans are roasted, finely ground, and then brewed to remove water. The solution is then dried by one of two methods:
– Freeze drying or Spray drying, and what is left is an extract of crystallized coffee grounds, which are rehydrated before use.

• Freeze drying

• Spray drying

There is one more method called agglomerate, which is the same as the spray-dried coffee process but has one difference.

• Coffee oils or other liquids are added to the spray-dried coffee while spinning in a tumbler, forming little instant powder granules instead of the powder that looks like instant coffee.

There are a couple of considerations on which method to choose, related to the cost and the flavour retained. In a nutshell, spray drying is a cheaper technology, and freeze-drying has the full flavour aroma of the coffee.

Spray drying process advantages and disadvantages.

Freeze-dried products advantages and disadvantages

The following steps in making instant coffee involve Aromatization and Packaging.

• Aromatization: Captured aromas lost during the early steps of the manufacturing process are sprayed on the dry coffee particles. This may be done during the packaging operation.
• Packaging needs to be done under low humidity conditions in a moisture-proof container to keep the product dry until purchased and opened by the consumer. Instant coffee is very susceptible to volatile oxidation and flavour release.
  • An increase in moisture content to 7%–8% is reported to be responsible for instant coffee “caking,” turning flowing powders or granules into a pastry or solid mass.
    Coffee must also be packed in jars with no more than 4% in-pack oxygen content and preferably less so that the shelf-life to acceptable quality is maintained for up to 18 months. If the moisture content is less than 5% w/w, it may last a few years.

Decaffeinated and Instant Coffees

Decaffeinated instant coffee was introduced by Nestle company in 1986.

In 1903, Ludwig Roselius, the head of the coffee company Kaffee HAG, accidentally discovered the secret to decaffeination. A shipment of coffee had been swamped by seawater in transit – leaching out the caffeine but not the flavour.
He created a method to steam the beans with various acids before using the solvent benzene to remove the caffeine.
These days, benzene is not used anymore, and a few different steps are taken than in regular coffee production.

One crucial step in decaffeination is starting when the coffee beans are still green.

According to Chris Stemman, the executive director of the British Coffee Association, “If you were to try and decaffeinate roasted coffee, you’d end up making something that tastes a bit like straw. That’s why, with 99.9% of decaffeinated coffee, the process is done at the green coffee stage. ²”

Methods to remove caffeine from coffee

There are different methods to remove caffeine almost completely. I’m using the word “almost” as a small amount of caffeine remains.

• Methylene chloride is a clear, colourless liquid used not just for the decaf process but also as an industrial solvent, paint stripper, and paint thinner.
• Ethyl acetate, meanwhile, is a natural fruit ether usually made from acetic acid, which in turn may be produced from natural ingredients or petroleum derivatives.

1. The Direct solvent-based process involves soaking the bans in either methylene chloride or ethyl acetate solvents. The prohibitions are then heated to remove the caffeine-soaked solvents.
2. Indirect solvent process: Coffee beans are soaked in hot water for several hours, and after they are removed, the water is treated with solvents, which adsorb and remove the caffeine. Then, the beans are added back to the water.
3. Non-Solvent Process – Both methods are similar in that the C02 binds with the caffeine molecules, drawing them out of the non-roasted bean.

Ultimately, if we chase the all-elusive perfect cup of brew, we will never be satisfied with the final product. But we will have fun if we look at the “chase” as a journey of discovering new flavours and experiences.

That also reminds me of people asking the bartender, “Can you make me your best drink.” Well, I’m afraid there is no such thing. The best drink is what you feel while drinking at that particular moment.
The same principle can also be applied when you are going to your local store looking to buy the best coffee, and since no such thing exists, as everyone has different tastes, I believe the questions we should ask ourselves are:

• What do I feel like drinking today?
• What flavours do I like to taste in my coffee?

Hopefully, having more information on what to look for in coffee will help us narrow our choices.

1. https://www.healthline.com/
2. https://www.bbc.com/future/article/20180917-how-do-you-decaffeinate-coffee