insight-coffee-101-from-plant-to-market

From Plant to Market

In various countries, in many areas of the world, coffee is the only source of income. A coffee tree is fruitful about 5-6 years after it’s planted. Its fruit is harvested and the beans are processed until they’re ready for market.

The life expectancy of a coffee tree is 20-25 years, and then they’re cleared and new trees are planted. The lives of most workers who are very poor and exploited by plantation owners, are focused on growing coffee.

The taxonomy of the Rubiaceae family was published by Carl Linnaeus (a Swedish researcher) under the title Species Plantarum in 1753. This same book is used by botanists today. The Rubiaceae family includes more than 500 genera and over 5,000 species of coffee trees.

The coffee plant genus contains more than 25 species grown in different parts of the world. Coffee beans grow on bushes and on trees that can be as high as 30 ft (9 m).

Generally, coffee plant leaves are green, but in some species their color varies from purple to yellow. Arabica and Robusta are the two main commercial species of trees developed in the world. A third, Liberica, is marketed in small amounts, but is economically insignificant.

coffee-berry

The Coffee Berry

The fruit of the coffee tree is cherrylike and the coffee is produced from the beans inside the “cherry.” Each fruit contains two coffee beans, covered with four layers.

Each bean is individually covered with a shiny greenish-yellow layer called the silver skin. The second thin, protective layer is called the parchment, which is similar to the skin of a pe anut (in the peanut the skin covers both halves).

The parchment is covered with a fleshy layer called “pulp” that is wrapped with the fruit outer skin. A unique phenomenon in coffee beans is the Peaberry – a coffee fruit in which each berry fruit holds only a single small, round coffee bean.

Only about 5% of the coffee cherries produce a Peaberry. arabica

ARABICA (The Pampered Tree)

As the most common coffee tree, the Arabica is about 65% of the coffee marketed in the world. It’s often called the “spoiled” coffee bean because it’s very sensitive to any change in weather conditions and grows in altitudes higher than 2,600 ft (800 m).

One frosty night is enough to destroy the annual yield. It’s also very sensitive to pests and diseases, but despite all the difficulties it causes growers, it’s a profitable crop. In general, Arabica coffee quality is considered to be very high and better than that of the Robusta (however, its quality doesn’t always measure up).

It contains a low amount of caffeine, has a rich taste, tantalizing aroma and pleasant acidity that leaves a slight taste of caramel in the mouth. Arabica is grown mainly in South America and in eastern Africa.

The two most common species of the Arabica tree are Typica and Bourbon. There’s been an attempt to hybrid Arabica trees with Robusta to overcome and improve the resistance of Arabica to pests and diseases, and to introduce more vigorous species that will be more productive with an improved taste. robusta

ROBUSTA (The Durable, “Robust” Tree)

The Robusta tree is grown mainly in Asia, South Africa and to a lesser extent, in America. It’s considered a much stronger, heartier tree than the Arabica (as implied by its name).

It’s more resistant to diseases and pests and in some regions can reach a height of more than 26 ft (8 m). It requires more precipitation and can be grown at sea level.

The Robusta is also more resistant to weather changes than the Arabica. While Arabica beans are rectangular and elongated, the Robusta beans are small and roundish.

The amount of caffeine in Robusta beans is almost twice as much as in Arabica, its taste is full and bitter, with low acidity, that leaves a slight astringent taste in the mouth.

Robusta vs Arabica

Robusta-vs-Arabica

Harvesting the Beans

harvesting-coffee-beansThe ripe cherry fruit is red. Not all of them ripen at the same time.

Three most common methods were developed to pick the majority of the fruit at its peak of maturation and to prevent rot.

Selective Picking

Skilled pickers harvest the beans, moving from one tree to another, selecting and picking each ripe fruit. It requires several picking rounds to obtain the best quality beans and to complete the harvest.

By using this method, growers improve the quality of marketed coffee and get maximum fruit production. However, this method is very expensive and not all growers can afford to use it.

Stripping

With this method, all fruit is picked in a single harvest. The harvest is planned for a date in which most of the fruit will be ripened.

The disadvantage of this method is that some of the fruit is unripe and some is overripe. Sorting occurs after the harvest. The fruit quality is lower and the yield is smaller than using selective harvest, but the cost is very low.

Mechanical Harvesting

In this method a big dune buggy-like machine drives over the trees, grasping each one and shaking it. Only ripened fruit falls into the machine’s container and the unripe fruit remains on the tree until the next harvest.

This newer method is better, the bean quality is good, and operation of the machine is very cheap. However, the machine itself is very expensive and not affordable to all growers.

Even more prohibitive, it can’t be operated on a mountain slope, a common coffee-growing terrain.

Fruit Processing

There are two main processing methods to extract beans from the coffee fruit – the wet and the dry process. The coffee taste is significantly affected by the method used. Each method has its advantages and disadvantages.

Washed (Wet) Process

Immediately after harvest, the beans are inserted into a large water tank. The spoiled cherries float to the surface and are removed. To release the ripe beans, the dipped cherries are pulped by mechanical crushing.

washed-process

The released beans are covered with pulp remnants of a sticky, jelly-like wet substance. To remove the remnants, the beans are fermented in a tank for 12-36 hours.

Later, they’re washed again and dried for several days in the open air or by a special drying machine. The dry beans remain coated with the parchment layer (termed “parchment coffee“).

In the past, removing the parchment was done manually, but it’s currently done by a peeling machine. After cleaning and sorting the beans by size, they’re ready for market.

Unwashed (Dry) Process – Natural Process

Drying in the sun is an age-old method, common in poor countries because it doesn’t require any special appliances. It’s also called natural processing. unwashed-process After the harvest, cherries are placed in the sun to dry in a 4″ (10 cm) thick layer on a clean surface – either on roofs or an allocated concrete surface.

For uniform drying, the workers frequently turn the spread beans with rakes. The drying process takes about two to three weeks. The fruit color changes to brown, its humidity drops to lower than 12% and one can actually hear the movement of the beans inside the dry fruit, when shaken.

Once the skin is fully dry, the pulp and parchment are removed from the bean.

Because this entire process is so lengthy, the beans absorb flavor components from the fruit and taste differently than in the washed process, containing more body and lower acidity.

Honey Process or Semi-Washed Process

In addition to Washed and Unwashed processes there is also Honey Process or Semi-Washed Process.

In this process the producer does not remove the entire mucilage layer, but dries the berries with some of the mucilage layer still surrounding the beans and they absorb part of the mucilage layer taste.

This process is very delicate, the beans must be turned constantly, otherwise the mucilage will ferment and decay, a process that will destroy the beans.

It is in use on specific plantations in various countries, such as Panama, Costa Rica and Indonesia.

Cleaning & Sorting

The processed fruit requires a second cleaning. During harvesting the beans are picked along with branches and leaves.

During the drying process, dirt and stones become mixed with the coffee fruit. And during the crushing and peeling process, broken beans and parchment remnants continue to contaminate the beans even further.

coffee-sorting

First, weeds and leaves are cleared by bellows. Then the beans travel along a conveyor belt while workers on both sides remove defective coffee beans. This process is repeated once more in some places where quality standards are exceptionally stringent.

Advanced mechanical methods used in some plantations increase the productivity by 200-300-fold more than in the old manual methods. In the current method the beans flow from a thin plastic sleeve into a glass tube in which a photoelectric system identifies defective beans, stones and other dirt pieces by their color and shape, and blows them from the tube.

Bean Classification

How do you judge good coffee?

This is the million dollar question (or maybe more). Many people in the world are skilled in determining coffee quality. In the end, customers and large commercial companies make the determination, but the road to the customer is long.

Coffee, one of the leading commercial products in the world (see Coffee in the World, page 153), is spread all around the globe.

Ideally, a uniform method to classify coffee would be used to allow fair trade. In World War II each country built a different classification scale.

Since then, there has been no global classification system for coffee suppliers – each country uses its own method. The standard scale used by major coffee suppliers – Brazil and Colombia – was adopted by many suppliers, and is determined by the percentage of defective beans and by bean size (screen size). Larger beans are considered of better quality.

Other classification methods used by coffee merchants around the world include screening by color, defects, cultivation altitude and region of growth, flavor and more.

Classification by Number of Defective Beans

One of the most common methods to determine coffee quality is by using a 10.6 oz (300 gr) coffee sample and measuring the amount of inedible and defective materials it contains. Each country has its own “defect” scoring table.

In Brazil, for instance, one negative score is equal to one black bean or to five broken beans, whereas a stone in the sample contributes two negative scores. Coffee quality is determined by the total number of negative scores.

However, different scoring values are used in different places around the world.

Classified by Size

Beans are placed on a vibrating conveyor belt, equipped with a perforated sieve with various hole dimensions. At the beginning of the conveyor, the holes are small, getting progressively larger along the belt.

bean-size

The measuring unit is usually 1/64″, thus referring to size 17 is 17/64″ (6.75 mm). Bean sizes range from 12-20. Generally, small beans (smaller than size 12) are unmarketable while size 20 beans are the largest.

Although grading by size is common in many countries, the relation to size differs among countries. Size 17 and larger is considered the best in some countries, but will be considered only good in others.

Classified by Altitude

Another sorting method is by plantation altitude above sea level – the higher the plantation, the harder the beans. Therefore, growers use the term “bean hardness” to grade the altitude of a coffee plantation.

grading-by-plantation-altitude-in-Guatemala

Very hard beans, graded SHB (Strictly Hard Beans) are usually grown at an altitude higher than 4,000 ft (1,200 m) and considered the best beans.

The coffee bean grading scale based on altitude in Costa Rica includes only two levels: SHB – above 4,000 ft (1,200 m) altitude and SH – from 2,600-4,000 ft (800-1,200 m) altitude. The scale in Guatemala plantation contains 8 levels.

Tastes of Coffee

It’s very difficult to describe the taste of coffee in writing. The SCAA (the Specialty Coffee Association of America@) created a structure to define coffee flavor “The Coffee Taster’s Flavor Wheel” which helps cuppers to describe coffee taste.

tastes-of-coffee

I have worked a lot with the SCAA coffee flavor wheel and I have trained cuppers to use it. The coffee flavor wheel is one of the best tools for cuppers to identify coffee flavor. For beginners or home users I have created a simple way to look at coffee taste – the coffee flavor pyramid.

To simplify matters, we can divide coffee taste into two categories – the actual taste and how it feels in our mouth.

flavor-pyramid

Cuppers describe the actual taste by comparing it to the four basic tastes we know- sour, salty, sweet or bitter (the existence of “umami” as a taste is debatable, and, I think, not relevant to coffee).

They also describe how the coffee feels in the mouth, in five basic terms: acidity, aroma, body, flavor and aftertaste.

If cuppers want to take taste description deeper to a second level, they will compare it to fruits, flowers, nuts, etc. Professional cuppers use another third level to describe sub-flavors.

For example if we taste flower, the sub-taste can be rose or jasmine.

  • Acidity

    It is the most significant coffee taste. It’s also mouthfeel. It describes the coffee’s crispness, not real acidity, but a feel of freshness under the tongue and inside the mouth. Comparing the acidity level between coffee varieties is fairly easy.

    Acidity in coffee feels delicate and soft, whereas coffee without acidity feels smooth and unified.

    For example, good South African Arabica coffee is very acidic and Robusta coffee from Indonesia is known for its low acidity. Coffee loses its acidity in time.

    Terms used to describe the level of acidity are: poor, soft, delicate or intense. Usually, acidity in the espresso cup is a good and positive flavor, but over acidity or sour coffee could imply a spoiled coffee.

  • Body

    This refers to the richness of coffee or to the "heaviness" (thickness) perceived in the mouth (which has nothing to do with weight). The coffee’s body characteristics depend on its source.

    Indonesian coffee is known as "heavy," whereas coffee from Central America is known as medium and at times even light. Descriptors use the terms full, medium, light, smooth, thick, rich and deficient/poor.

  • Aroma

    It is the pleasant scent of coffee. When the cup is near the nose, we’re flooded with the smell of coffee.

    Everyone knows the engulfing sense when a fresh package of coffee is opened. The terms used to describe the aroma are: juicy, spicy, floral, or even brackish and earthy.

  • Flavor

    It is the taste in the mouth after the acidity, aroma and body are neutralized.

    The terms used for better description of flavor are: piquant, chocolatey, fruity, flowery or terms describing bad coffee taste: heartburn, bitter, old, musty or moldy.

  • Aftertaste

    It is the lingering taste remaining in the mouth after swallowing. Sometimes it disappears after a short time and Sometimes the taste stays for quite a while.

Tasting Coffee – Cupping

Tasting takes coffee one step closer to the customer. This has to be done at each of the three major stages in the process: when the farmer sells the green coffee to the supplier, when the supplier sells the coffee to the dealer, and when the dealer sells it to the roaster.tastes-of-coffee-cupping

The tasting procedure, called “cupping,” is used to classify the green beans and confirm their quality. Those are the major checkpoints, but there can also be as many as five or even seven steps in the selling process.

Still, the last step is always the roaster. Although time consuming, the process ensures each purchaser they’re getting the quality beans they paid for.

However, despite the best efforts of coffee growers, unexpected problems can occur throughout the processing stages – prolonged fermentation, wetting the beans during transportation or other mishaps that can potentially change the quality of bean taste, even when to the eye, bean size, color and purity seem good.

To decide whether or not to buy the beans and how to estimate their worth, coffee merchants are accompanied by teams of professional cuppers.

In addition, many organizations in the world conduct tasting competitions and grade the best growers and their merchandise. In commercial cupping a small sample of green coffee beans is roasted in a small lab roaster, ground immediately, infused in just off-boiling water and tasted.

The tasting test for the end customer is somewhat different. After the beans are roasted to the required stage, they’re kept for a few days before tasting.

Cupping is considered an art. The cupper must be able to taste between 20-30 types of coffee without losing the ability to recognize the unique quality of each type. The evaluation of two cuppers is never identical, but must be very similar.

The Amazing 4 Cup Espresso Flavor Experiment

Espresso is a very complex beverage. Espresso’s taste is influenced by many parameters like suitable grinding, the quality of the espresso machine, brewing time, the barista’s skills and more.

One of the best ways to demonstrate the vast range of espresso flavors is the amazing “4 Cup Espresso Flavor Experiment.” Prepare one espresso shot, but instead of making it into one espresso cup, replaced the espresso cup every 6 seconds. You will get 4 espresso cups with a small amount of coffee in each one of them.

Now taste them from the first cup to the last. You will get a different taste in each cup. The taste will change from the first cup that will be intensive, full of flavor with good body and acidity – to the last one that will be watery and bitter. Hence we can understand that when we drink a quick espresso, we actually drink a composition of all four cups.

The Cupping Process

The table is usually set with several cups, each labeled with a number, to avoid identification of the coffee type. A sample of the roasted coffee and a sample of the green coffee bean are set in saucers for visual impression.

Every cupper receives an evaluation form for comparison in which he notes his impressions while tasting (a sample form is presented in the Appendix). When a single origin is tasted, it’s customary to compare it to a known typical batch.

cupping-process

On the other hand, in competitions, there’s no need for comparison since the objective is to identify the best batches among the cupped samples.

Usually, cuppers use a flat, wide spoon made of non-reactive metal. The spoon shape increases the amount of particles spraying into the mouth with what we call a “slurping” action.

Cupping stages of the green bean: (SCAA defined standards for professional cuppers1)

1 – The beans are roasted to “City” stage.between 8-12 min.

2 – The beans are coarsely ground to French press size.

3 – The cupper smells the ground coffee sample and the bouquet impression is recorded. This action is termed “dry coffee aroma.”

4 – A full teaspoon of coffee (8-8.5 g) is placed into a 150 ml glass. Hot filtered water just off the boil (196-203°F [91-95°C]) is added and after about three minutes, the coffee settles down and most of its particles sink to the bottom of the cup. A thin layer of ground coffee particles floats on the surface of the liquid. This is called the crust.

– The cup is brought to the nose and smelled – this is called the aroma “before the break.”

– “Breaking the crust” – at this stage the crust is broken with a spoon, creating a “knock” of good coffee smell. The aroma released is called “after the break.”

7 – The teaspoon is washed in water and the action is repeated with each glass. The cuppers must note all their impressions on the evaluation form. (see example for Cupping Form, page 211).

8 – At this stage the crust is removed from the coffee with a teaspoon and five minutes later, the coffee temperature has dropped until it is suitable for drinking.

Now comes the moment of truth – the tasting! This method is known as the Three “S’s”: “Smell, Slurp and Spit.” All the activities are noisy and create a unique environment for coffee cuppers.

The teaspoon is filled with coffee, brought to the mouth and smelled noisily, while inhaling deeply through the nose to sense the aroma.

The coffee is slurped noisily, accompanied by a deep inhale (very much like sipping soup without table manners). The coffee is swished around the mouth.

The coffee is spat out into a spittoon.

9 – The results of the cupping are recorded.

10 – This procedure is repeated with another cup of the same batch, and in each tasting, the cupper concentrates on one taste at a time. One tasting determines the acidity and another determines the body (writing down the feeling is essential).

11 – The mouth is washed with water (some claim that sparkling water is better) before another batch is tasted.

Each batch is tasted by several cuppers, and the results are compared at the end of the process. Generally, the results are different, but close enough to reach the right decision about the coffee quality.