Coffee Beans – From Picking to Roasting

Clusters of coffee beans UK grow along the branches of trees. The exocarp is the cherry’s skin, which is bitter and thick. The fruit beneath, the mesocarp, is lovely and has a texture similar to that of a grape. Then there’s the Parenchyma, a sticky, almost honey-like covering that shields the coffee beans within the coffee cherry. The beans are protected by the endocarp, a parchment-like envelope that protects the green coffee beans, which also have a final membrane termed the spermoderm or silver skin.

Coffee is often chosen manually in one of two ways. Cherries can be stripped off the branch in bulk or individually using the selective picking method, which guarantees that only the ripest cherries are harvested.

Processing of Coffee Cherry

They must be processed promptly after they are plucked. Coffee pickers can harvest between 45 and 90 kg of cherries each day, and however, only around 20% of this weight is coffee beans. Cherry juice can be extracted in one of two ways.

The Dehydration Process

This is the simplest and most cost-effective method, as the collected coffee beans UK are left out in the sun to dry. They are kept in the sunlight for around 7-10 days and are turned and raked regularly. The objective is to reduce the moisture content of coffee cherries to 11%, at which point the shells will become brown, and the beans will rattle inside the cherry.

Wet Procedure

The wet procedure is distinguished from the dry method by removing the pulp from the coffee cherries within 24 hours of harvesting the coffee. After removing the outer shell and pulp, the beans are sent to fermentation tanks, where they might sit for up to two days. Naturally occurring enzymes dislodge the beans’ sticky parenchyma, subsequently dried in the sun or with mechanical dryers.

The dried coffee beans are then hulled, eliminating all layers. After that, the coffee beans are moved to a conveyor belt and graded according to their size and density. This can be done manually or automatically with the aid of an air jet to separate lighter weighing beans deemed inferior. Countries that harvest coffee ship it unroasted; this is called green coffee. Annually, around 7 million tons of green coffee are exported worldwide.

Roasting Coffee

Coffee roasting alters the chemical and physical properties of green coffee beans and is responsible for the coffee’s flavour.

Green coffee beans are cooked to around 288°C in big rotating drums, and the drums’ revolving motion prevents beans from burning. The green coffee beans initially become yellow and have a popcorn-like scent.

After approximately 8 minutes, the coffee beans ‘pop’ and double in size, indicating that they have reached a temperature of 204°C; they then become brown due to the release of coffee essence (inner oils). Pyrolysis is the term used to describe the chemical reaction that results in the flavour and aroma of coffee when heat and coffee essence combine. A second ‘pop’ indicates that the coffee is fully roasted between three and five minutes later.