Coffee processing is the method of turning coffee cherries into the beans we all know and love. The goal is to extract the coffee seeds (beans) from the cherry, and the processing method plays a huge role in shaping the final flavour of your coffee. Think of it like grapes and sultanas—both come from the same fruit, but the flavours are completely different.

Understanding how coffee is processed begins with the coffee cherry itself. It looks like a regular cherry but contains two seeds. From the inside out, there are the coffee seeds (or beans), a parchment skin covering them, a sticky mucilage layer, the flesh of the fruit and the outer skin. The mucilage and flesh contain the highest concentration of sugar and are the most active elements in terms of imparting flavours into the coffee beans during processing. There are three main methods of processing: Unwashed, Semi-Washed and Washed.

Glossary Of Terms:

• Pulping: The process of removing the outer flesh of the coffee cherry from the seeds.

• Fermentation: A process used to break down the sticky mucilage layer to make it easier to remove.

• Hulling: The removal of the parchment skin that covers the coffee beans.

UNWASHED (AKA Natural or Dry Process)

In the unwashed method, the whole cherry is dried with the fruit still attached to the seed. This process allows the beans to absorb more of the fruity flavours over a longer period. It’s the oldest and simplest technique that works best in dry climates where the cherries can slowly dry without rotting or developing mould.

Once the cherries are dried to about 10-12% moisture, the dried fruit is removed from the seed using a machine called a huller. This machine works much like a parmesan cheese grater. The dried coffee is placed around a rotating perforated cylinder that peels away the dried fruit. The beans are then cleaned, graded for size and quality, and sold to coffee buyers. You might have come across terms like 'Grade 1', 'AA', or 'Fancy'—these refer to different grading systems used in various coffee-producing countries.

As this method has an extended period of contact time between the coffee bean and the coffee fruit, it tends to produce bold, fruity and often wine-like flavours, making it popular among those who prefer rich, complex coffees. Although this is the simplest method, it also has the greatest risk of producing undesirable flavour profiles.

SEMI-WASHED (AKA Honey Process, Pulped Natural or Wet-Hulled)

The semi-washed method involves partially removing the outer skin of the coffee cherry while leaving the sticky mucilage and some fruit intact during drying. This method creates a balance between the fruity sweetness of natural coffees and the cleaner flavours of washed coffees.

In the honey process (also called Pulped Natural), the coffee cherries are de-pulped, leaving the mucilage on the beans as they dry. The term "honey" comes from the sticky appearance of the beans during this stage—not because actual honey is involved. The amount of mucilage left can affect the flavour; more mucilage can lead to a sweeter, more syrupy flavour.

A variation of this method, known as wet-hulling, is unique to Indonesia. Here, the cherries are de-pulped and the mucilage is washed off. The coffee is dried until it reaches about 30% moisture and then the parchment is hulled while the beans are still damp. Because the beans are still quite soft at this stage, they can become slightly mis-shapen. The reason for hulling while the beans are still wet is Indonesia’s high humidity. Farmers are concerned that leaving the beans to dry too long could lead to mould, so they speed up the process.

Semi-washed coffees often have complex, honey-like sweetness and are popular for their balanced flavours that fall between natural and washed coffees.

WASHED (AKA Wet Process or Fully Washed)

The washed process is the most common method for producing high-quality coffee. It involves removing the fruit and sticky mucilage from the beans early in the process, allowing the flavours of the bean itself to shine through.

First, the cherries are de-pulped and the beans, still covered in mucilage, are soaked in water to ferment. This fermentation process breaks down the mucilage so it can be easily washed off. There are two types of fermentation: dry fermentation (without water) and wet fermentation (soaked in water). Dry fermentation is faster but riskier, as it exposes the beans to air and higher temperatures. Wet fermentation is slower and allows for more control. The goal is to stop fermentation as soon as the mucilage breaks down, because over-fermentation can lead to unpleasant flavours, like alcohol or yeast (think vegemite).

After fermentation, the beans are rinsed and dried. If the weather is favourable, this is done outdoors on cement patios or raised drying beds. Raised beds allow air to circulate around the beans, ensuring even drying. In areas with less predictable weather, mechanical dryers (similar to large tumble dryers) may be used.

Once the beans are dried to the desired 10-12% moisture level, the parchment skin is removed and the beans are cleaned and sorted.

Washed coffees are known for their clarity, clean taste and bright acidity. They tend to highlight the natural flavours of the coffee variety and the region where it was grown.

Processing Risk Factors

Each stage of processing carries risks that can affect the coffee’s quality. Picking cherries that are too ripe or under-ripe can lead to poor flavours. Fermentation must be carefully monitored; too short and the mucilage won’t break down properly; too long and the coffee can develop off-putting fermented or alcoholic flavours. Drying is also crucial; if done improperly, the beans can develop mould, or dry unevenly, which can affect the coffee's shelf life and flavour.

Every step in processing requires careful attention. When done correctly, it leads to high-quality coffee. When mishandled, it can result in defects that spoil the final cup.

So, HOW DOES THIS AFFECT MY CUP OF COFFEE?

Different processing methods result in different flavour profiles, so choosing coffee based on its processing method can help you find what you like best:

• Washed Process: Known for clean and sweet flavours. Ideal if you enjoy a clear, well-defined flavour.

• Semi-Washed (Honey Processed): Produces rich, honey-like sweetness and a slightly heavier body. Great for those who enjoy sweet but balanced coffees.

• Unwashed (Natural Processed): Offers bold, fruity flavours, often with wine-like complexity. Perfect if you prefer intense, rich coffees.

At Omar’s, we appreciate all processing methods but tend to favour Washed coffees for their sweetness, clarity, and ability to highlight the coffee's origin. There’s no single “best” method—it’s all about your personal preference.