UNDERSTANDING COFFEE PROCESSING

When discussing coffee there are some basics that can help give you a better understanding of what you are drinking and what was involved in making that delicious cup of joe. In this topic I want to introduce some basic concepts to expand your knowledge on different processing methods as well as cover some basics to help you to be able to pick up any bag of coffee and not feel overwhelmed.

Understanding origins and blends

Depending on who roasted your coffee you might notice ‘Origins’ followed by a ‘Process’ such as ‘Washed or Natural’ or maybe you have multiple ‘Origins’ such as ‘Ethiopia Washed’ & ‘Brazil Natural’ This is called a coffee ‘Blend.’ A blend of coffee is on most occasions determined by the roaster and decided on for many reasons. Some of these reasons have to do with seasonal availability, maybe there is an odd bag of coffee that needs to be used up and is incorporated into a seasonal blend, or on most occasions a coffee blend can offer a roaster freedom of expression, it can add that unique selection of different coffee from all over the world to create a blend of coffee only available from that roaster and sometimes that cafe.

Depending on the roaster you can commonly find an espresso blend, filter blend, single origin a decaf and maybe a seasonal blend too, we have covered seasonal blends and single origins but what is the difference between a filter blend and an espresso blend and where does decaf fit into all of this?

What is the difference between espresso roast and filter roast?

Both espresso and filter roasts are made by blending and roasting green coffee beans to brown.There are a couple of differences to keep in mind when distinguishing between the two.

Typically espresso roasts are darker roasted beans and the beans used are specifically chosen to compliment milk based drinks or to be drank alone as an espresso.Filter roasts are generally lighter in colour and are much more fruity and bright in flavour. You can have a really light espresso and you can even grind up an espresso blend and use it for filter, the tasting notes will change slightly as they have been roasted with the extraction method in mind but experiment with it, you might just like it.

What is decaf?

Decaf is the term used to describe a process that removes caffeine. This process is used with coffee as well as tea and is important to remember that some decaffeinated coffee can still contain caffeine after the decaffeination process. There are a couple different processes used to remove caffeine, some utilise chemical solvent and other processes utilise non-solvent methods. ‘Swiss Water Decaf’ use a popular process to remove caffeine without using any harmful chemicals. The entire process is complicated but in summary water is pushed through coffee to remove the caffeine and simultaneously some flavour as well. The water used contains both the caffeine and flavouring, it is run through a filter that isolates and traps the caffeine and the water containing just the flavour is returned back to the coffee beans. ‘Swiss Water Decaf’ removes caffeine content in their coffee to a target of 99.9% caffeine free. The goal of their process is to ‘remove caffeine without having any impact on flavour or roast profile.’ If you are interested in leaning more about this process check out the video below.

Circling back to coffee processing methods there are couple of basics we need to cover first.

Coffee starts off as a seed, this seed grows into a tree and on this tree is a cherry. this cherry is the fruit of the ‘Coffea’ plant and inside this cherry are usually two seeds covered in a parchment layer, this parchment layer itself is also covered in another layer known as mucilage. In-between the mucilage and the outer skin of the coffee cherry is the pulp of the fruit.

Before the cherry is picked all of the variables such as varietal, origin, masl (altitude) etc are predetermined. It is only after the cherry is picked that the different processing methods come into play and are defined by how the green coffee is removed from the cherry also known as the ‘Process’.

Natural

Naturally processed coffee is the oldest coffee processing method. Once the coffee cherry is picked it is sorted and only the most immaculate ripe fruits are used. The cherries are laid out on raised beds to dry and are turned intermittently to ensure even drying, as soon as the cherry is picked from the plant it starts to ferment. The fermentation is accelerated when the drying process takes place so this intermittent agitation also helps to prevent mould. The entire drying process is complete once the coffee beans moisture content reaches around 11%, which can take up to a month. After the coffee cherry is dry it is then run through a hulling machine or similar device to remove the fruit and parchment layer leaving behind only the green coffee beans.

Washed

Washed processed coffee is a much quicker process in comparison to naturally processed and the flavour profile is much more clean and can often offer a bright crisp acidity to the cup. The flavours present in washed coffee are less reliant on the sugars from the fruit instead the altitude, geographic location and washing method are much more perceivable to the resulting taste.

This process begins with picking ripe fruit, ensuring that the fruit is in fact ripe can be done so by colour, feel and a float test. After the most ripe fruit is selected it is quickly de-pulped, this is usually done by a machine called a ‘de-pulper' and happens between 8-12 hours after the fruit is initially picked. After the fruit has been de-pulped you are left with the coffee seeds surrounded by their sticky mucilage and this is transferred into a fermentation tank to rest over night.

Fermentation helps to loosen the mucilage from the seed and in turn makes it easier to seperate the two.

The following morning the coffee beans are submerged with water and agitated, this action removes the mucilage from the seed and is repeated multiple times until all the seeds are left in their parchment layer. This parchment coffee is now sorted and spread across covered drying tarps, they are constantly agitated and flipped around to ensure even uniform drying for up to a week before the desired moisture content of around 11% is reached.

In most cases the parchment is removed by a hulling machine leaving behind only the green coffee beans prior to export.

Honey

Honey processed coffee’s main point of difference is that it is dried in its mucilage layer. Depending on how and how long the coffee is dried will help to determine what colour the final product will be, for instance a yellow honey will be dried fairly quickly with lower levels of fermentation while a red or black honey will rely heavily on the fermentation flavours caused by a much longer slower drying out process.

Just like the washed and natural process the very first step is to pick the cherries, only the most ripe cherries are used and similarly to washed processes need to be de-pulped fairly quickly, Usually within 8-12 hours of picking. In this de-pulping process the skin and pulp is removed but the mucilage is left on the beans. The beans are then dried out with the parchment and mucilage still in tact, this drying process usually takes around 2-3 weeks before the beans reach a moisture content of 11%. When ready to be exported the parchment is removed leaving only the green coffee beans behind.

It is important to note that in all of these processes we have described them in a general way and each and every farmer processes their coffee slightly different. For example some farms can’t rely on using much water as it is scarce and so a dry de-puling machine is used in stead of a wet de-pulping method. In simple terms there are many ways to process coffee all of which result in different flavour profiles and curious coffee characteristics.