All About Coffee Beans | From Coffee Cherry to Beans

The coffee plant is a special crop which, starting in Ethiopia, has now covered large areas of tropical and subtropical cultivation. Coffee trees belong to the family Rubiaceae and the tribe Coffeeae.

Currently, more than 100 species of the genus Coffea are known. The evergreen coffee plants produce white flowers which, after fertilization, produce mainly red fruits called coffee cherries.

Coffee trees can naturally grow to over 30 ft/9 m. But producers prune and stump plants short to conserve the plants’ energy and to help to harvest. Smaller trees have better yield and quality in a limited space.

The coffee tree is unique because it grows in a continuous cycle. So, it’s usual to see flowers, green fruit and ripe fruit simultaneously on a single tree.

The unripe cherries are green; over time, they turn red, yellow, orange, or even pink, depending on the variety. And as they ripen, they grow increasingly sweeter.

It takes nearly a year for a cherry to mature after first flowering, and about 5 years of growth to reach full fruit production.

The beans we roast, grind, and brew to make coffee are the seeds of a fruit. The coffee plant produces coffee cherries, and the beans are the seeds inside.

The National Coffee Association USA states that the average coffee tree produces 10 lbs of coffee cherry per year, which results in around 2 lbs of green beans.

Coffee cherry (coffee bean is actually the seed inside of a coffee cherry) is a fruit, or berry of the coffee tree, growing in clusters along the plant’s short stems.

Each tree is covered with green, waxy leaves growing opposite each other in pairs. Coffee cherries grow along the branches.

The fruits are similar in appearance to berries. They start green, and as they ripen, they turn redder. After being picked, the skin and pulp are removed and what’s left is the seeds.

The seeds are eventually roasted, and are then known as “coffee beans”. After harvesting the coffee cherries, there are different ways to produce coffee beans.

The different parts of the coffee cherry have an impact on the processing methods and as a result on your coffee’s final profile. Let’s take a look at the basic anatomy of the coffee cherry to better understand our daily brew.

The main parts of the coffee fruit or cherry are a coffee bean (seed): the silver skin, parchment, pulp, and the outer skin or pericarp.

Anatomy of a coffee cherry – courtesy www. Researchgate. Net

Outer Skin (Exocarp or Pericarp)

Exocarp is the outer skin of the fruit that covers coffee cherries. When fruits only start to develop and grow, they have green skin, but when they mature, it turns yellow and eventually becomes red when the fruits are ripe.

Mucilage or Pulp (Mesocarp)

Mucilage or mesocarp is also known as the “flesh” of the coffee fruit. The main thing about this part of a coffee cherry is that it is very sweet due to the high sugar content and it has a great impact on the taste of the bean.

During the honey process method, at the drying stage, if they leave this mucilage with the bean the coffee will develop a natural sweet note.

Pectin Layer (Parenchyma)

It is the protective layer of the coffee bean and is made up of cellulose. It is located beneath the mesocarp and surrounds the coffee seeds (beans). It is a sticky, honey-like layer and is also called the parenchyma.

This third layer of the pericarp protects the beans and is primarily made up of cellulose with small amounts of pectin.

Parchment (Endocarp)

It is the innermost layer of the pericarp and is the layer that covers and protects the bean, has a pale yellow colour and is of a hard and fragile consistency when it has dried. It is formed from 3 to 7 layers of sclerenchyme cells.

The coffee bean coated with this protective layer is often called parchment coffee and in some countries, it is the way coffee is marketed. The parchment layer should be removed before roasting the coffee.

Silver Skin (Epidermis or Perisperm)

The perisperm or epidermis is also known as silver skin, which is the outermost layer that surrounds the seed.

Some remains of the silver skin remain adhered to the bean and detach themselves totally or partially during the coffee roasting process.

Coffee Bean (Endosperm)

Most coffee cherries contain two beans. The only exception to this is a peaberry that is a natural mutation. With all the coffee that is harvested each year, about 5% of berries have a single bean inside which is called a peaberry.

Endosperms usually have a hard consistency and greenish or yellowish colour. The chemical content of the endosperm is very important since it is the foundation of the flavour and aroma of roasted coffee.

Centre Cut (Embryo)

The centre cut hold the embroy. The embryo is the second inner part of a coffee bean & is the heart of a coffee bean. It is located on the convex face of the endosperm.

The embryo is composed of a hypocotyl (embryonic axis) and two cotyledons and has a length of 3-4 mm. It grows and develops due to the nutrients that it gets from the endosperm that surrounds the embryo.

A Peaberry is a natural mutation. With all the coffee that is harvested each year only about 5% has a single bean inside which is called a peaberry.

Peaberries can be an anatomical variation of the plant or they can form when there is insufficient pollination and one ovule isn’t fertilized.

Sometimes the seed simply fails to grow due to genetic causes or environmental conditions. Peaberries usually occur in the parts of the coffee plant that are exposed to severe weather conditions.

There is some debate over whether peaberries have a sweeter and more desirable flavour. Regardless of whether you think they taste different, their rounded shape allows for better rolling in the roasting drum.

Peaberries are kept apart from other beans to avoid an inconsistent taste after roasting and are sometimes sold at a premium.

Coffee is consumed for its stimulating and refreshing effects, which are influenced by a complex mixture of biochemical constituents.

Coffee is often used as an antioxidant, but more importantly coffee is a good source of chromium and magnesium that assist in controlling blood sugar by ensuring proper usage of insulin.

The main constituents of coffee are caffeine, tannin, fixed oil, carbohydrates, and proteins. It contains 2–3% caffeine, 3–5% tannins, 13% proteins, and 10–15% fixed oils.

In the seeds, caffeine is present as a salt of chlorogenic acid (CGA). Coffee also contains oil and wax.

Amino Acids

Amino acids are important for protein building in the human body and are present in coffee beans too.

Free amino acids disappear from coffee beans during the roasting process, but still, there are plenty of these acids in your coffee. It contains glycine, glutamic acid, and aspartic acid.

Carbohydrates

Carbohydrates make up about 50% of a coffee bean and the soluble sugars of roasted coffee contain soluble sugars of glucose, sucrose, and fructose.

Green coffee contains 6–7% of sucrose as soluble sugars & a low amount of glucose. Most of the carbohydrates present, such as cellulose and polysaccharides consisting of mannose, galactose, & arabinose, are insoluble.

Fibre

Coffee beans have nutritious indigestible dietary fibres. Traces of fibre have been found in brewed coffee. They help in keeping control of your cholesterol and absorption of nutrients.

Minerals

While the amount is rather small but a variety of minerals are found in coffee beans.

These include minerals such as zinc, calcium, phosphorous, magnesium, and potassium. Moreover, there are vitamins like thiamin, folate, vitamin B-6, niacin, and riboflavin as well.

Caffeine

10% of the caffeine and about 6% of the chlorogenic acid are present in a coffee drink. During the roasting process, the caffeine level in beans decreases.

Now, that you know the coffee beans let’s read and understand the different types of coffee. When you ask what different types of coffee are? It may refer to various things like:

• The type of coffee plant
• The level of coffee roast
• The coffee brewing method used
• The type of drinks prepared with the brewed coffee

The difference between broad categories of hot or cold coffee will depend on the type of base coffee, whether you added the milk, the ratio of coffee to milk, and other ingredients.