Everything about Coffee Processing

October 08, 2020

If you have been enjoying lots of single origin coffees, you probably notice the word ‘Processing’ stated on the label.

This post we breakdown all types of coffee processing & important things that you need to know. It's quite a long one, do make yourself a coffee first before you start this post. Let's go!

 

liberica tree

Coffee beans come from the seed of coffee cherries, it needs to be processed to turn into green beans in order to make it stable for storage and export to all around the world 🌏

Of course, there are dozens of methods to process the coffee cherries. Let’s start with the most commonly seen processing, Washed! 💦

 

washed coffee

Washed Processed

Coffee cherry has 2 layers to remove, cherry skin & parchment. In between them, there is mucilage that’s sticky flesh covering the parchment.

Once cherries are picked, it goes into a floatation tank to separate ripe & unripe cherries. Ripe cherries sink to the bottom and unripe cherries float on top. 

 

depulper

Depulper machine removes cherry skin

Next, the ripe good cherries go into depulper to remove the outer cherry skin, then the seeds (with mucilage & parchment on) goes into fermentation to remove the mucilage. 

The aim for the washed process is to remove all the mucilage from coffee seed before its dried. Fermentation breaks down the mucilage and makes it easy to wash away with water.

After fermentation & mucilage removed, the seeds (with only parchment on) are then going to drying stage until it’s around 12% humidity. 🌞

Once done drying, it’s rested (with parchment) for 1-2 months to stabilise for export. In the end, it’s hulled to remove parchment, sort, grading and bag it up for export. 🚢

 

washed drying coffee

Washed beans with parchment on drying bed

As the mucilage is removed in the early stage of the process, washed coffees often exhibit delicate and soothing aromatics.

You’ll usually find more pronounce floral qualities like jasmine note in washed coffees and delicate fruity notes like peach, apricot and cherries etc. 

You can check out all the washed coffees here. Next, it's a simpler one, the honey processed

 

 

honey processed coffee

 

Honey Processed 🍯

One of the most common questions we got is, is Honey Processed means honey added into processing?

Nope, there is no honey added for the honey process, but rather the colour and smell of beans (with parchment during drying) that resemble honey! It will cost a fortune if honey is added 😅

 

Hand picked only the ripe red cherries

After ripe cherries are picked, the cherries will depulp right away to remove the outer cherry skin. Then the beans (with mucilage and parchment) is left overnight for fermentation and it’s bring to drying on the patio or raised beds, usually takes about 7-14 days of drying depending on the weather.

Once the beans are dried to 11-12% moisture level (a safe moisture content for storage and shipping), its rest for 1-2 months to stabilise, then hull to remove parchment, grading sorting and bag up for shipping.

 

drying on raised bed

On the exact opposite of washed, the honey process does not involve water during the entire processing. This saves water and time for coffee producers.

The concept of Honey Process is similar to other processing like pulped natural from Brazil or giling basah (Wet Hulled) from Indonesia, but there are differences in fermentation and drying stage. We can also call them semi washed too.

 

honey processed coffee beans

As the beans are ferment without washing the mucilage, the sugars in mucilage will go into the beans and this increase the sweetness & body of the coffee.

If you compare with the same beans, honey processed coffees have better sweetness and fuller mouthfeel than washed coffees. Also, you’ll find more complexity in honey processed coffees too 😋

Check out all the Honey Processed (semi washed) coffees here.

 

natural processed coffee

Coffee cherries dry in whole

Natural Processed ☀️

Like its name, natural process is pretty straight forward and also does not involve water (like honey process) to process the coffee cherries. 

Once ripe cherries are picked, it goes straight to drying in whole cherries. As there are more layers in cherries (with cherry skin, mucilage & parchment), it takes the longest time about 3 weeks to complete the drying stage. 

 

natural processed coffee cherries in whole

Whole coffee cherries after 3 weeks of sun dry.

After sun drying, it goes to resting, hulling, sorting, grading and in the end bag up for export. 

As the coffee cherries are dried in whole, all the sugars in cherry skin & mucilage go into the beans. Also, the fermentation process happens simultaneously throughout the drying stage. 

 

hulling

Hulling to remove dried cherry skin.

As a result, you’ll get a much sweeter & greater complexity in the cup. Also, the natural process coffees have better mouthfeel like thick fruit juice 😋

If you have been tasting lots of natural processed coffees, you’ll notice there are similar characteristics like mango, pineapple & tropical fruits flavour profile 🥭🍍🍌

Check out all the natural processed coffees here 

 

My Liberica documentary shows washed, honey & natural processes 

Wanna try all 3 different processing of coffees at once? The Liberica Trio has all 3 washed, honey and natural process coffees in medium roast, the perfect combo for coffee tasting. Check it out here. 

 

anaerobic & carbonic meceration

Coffee cherries after anaerobic fermentation in Sabarica.

Anaerobic & Carbonic Maceration 

At this point, you probably notice that we mentioned 'fermentation' in every processing.

The fermentation stage in coffee processing places a very significant role, it’s the stage where beans develop a better complexity in flavours and aromatics 😋

The main challenge is to control the rate of fermentation. Oxygen and temperature are the main drivers of fermentation, it’s difficult to control the rate as most fermentation is done in an open area and fluctuating temperature.

Under ferment will result in coffee that’s lack of flavours and taste boring, whereas over ferment results to the intense flavour of fermentation like dried mango or worse rotten flavours 🥴

 

fermentation tank

The aim of anaerobic and carbonic maceration (CM) is to control the rate of fermentation, usually done in an enclosed stainless steel fermentation tank and indoor to keep a stable temperature throughout the fermentation.

Once the seeds enter into the fermentation tank, it’s sealed up to ensure no air goes in. During the fermentation process, the sugars are broken down by bacteria and carbon dioxide is released. A one-way valve on tank releases excess carbon dioxide that builds pressure while preventing oxygen from going into the tank. 

 

fermentation tank

Anaerobic natural (in whole cherry), water filled to top ensure zero air in  fermentation tank

After fermentation, it goes straight to drying, resting, sorting, grading and lastly bag up for export. The photo shows the cherries that had done anaerobic fermentation in whole cherries In Ranau Sabah ⛰

The difference between anaerobic and carbonic maceration is that CM involves carbon dioxide pump into the tank to ensure no oxygen is present during fermentation, while anaerobic does not pump CO2 in.

 

Sun dry on raised bed after anaerobic fermentation

Sun dry on raised bed after anaerobic fermentation

One key difference between anaerobic & CM compare to normal fermentation is that there is pressure involved during the fermentation inside the tank. The pressure from CO2 buildup forces all the flavours and sugars into the beans. 

As a result, this amplifies the intensity of flavours and sweetness to the next level. Also, it gives superb complexity of aromatics like a floral & super juicy cuppa 😍 

If you love super intense fruity floral coffees like us, you have to check out anaerobic processed coffees here ☕️

 

defects

Defects 🥴

In every agriculture products, there are definitely defect produces. Hence, sorting & grading are ways to eliminate defects and separate into different sizes. Same goes to coffee beans! 

In coffee farms, cherries pickers are trained to pick only the ripe cherries. But for sure, unripe cherries may accidentally pick and go together with ripe cherries 😕

 

remove unripe beans

Remove unripe floating coffee cherries.

The floating tank is the easiest way to remove unripe cherries (quakers). Of course, sorting during the drying stage is also a way to remove unripe cherries for honey and natural processed. 

Other defects include empty shells, insect damage, mould & fungus etc. Yes, it’s bad to drink these defects. 

These defects can only be removed by labour hand sorting 👐🏼  Of course, there are machinery like density bed to sort it, but humans touch is still crucial during the coffee processing 🤚🏼

 

cupping

Cupping to score the coffee

One of the main criteria on high quality specialty grade coffee (cupping score 80 points above) is minimal to zero defects. The higher the cupping score, the lower the defects 🤗

As you can imagine, the lesser the defects in the beans, the more labour work go into sorting. A batch of beans would have gone through several times of sorting to ensure zero defects. 

The removed & rejected defect beans are usually sold to local traditional or instant coffee makers at dirt cheap low price. 

 

Sorting in every stage ensures zero defect coffees

As a result, it’s very costly & labour intensive to produce zero defects in specialty grade coffee. The more sorting, the lesser defects, the higher the cost, the higher the price. 

This is why specialty grade beans cost way higher than commercial grade beans, you pay what you get 😉

Now you know why there are cheaper range of beans from big brands and supermarket shelf. You know what you can find inside 🤢

 

Defect beans

Defect beans to remove in after roasting by Ghostbird Coffee

One easy way to spot defects is by checking the beans one by one before you grind it. Any beans that look weird and lighter colour (quakers) are defects 🤏🏼 

The unripe beans, quakers have high acid content than full ripen beans. This is why you heard that people get stomach upset after drinking coffee. It's definitely low commercial grade natural processed beans that have loads of quakers, you can imagine drinking a cup of acid ☠️  Moral of the story, stay away from commercial beans.

Thankfully, all our roasters do a final last sorting after roasting to ensure as little defect as possible goes into the coffee bag 🙌🏼 

 

 drying bed

Drying bed in My Liberica

Drying & Shelf Life 

The drying stage is a crucial yet challenging stage in coffee processing. It also the stage that takes a longer time and lots of labour 💪🏼

The ideal drying duration range from 7 days to 21 days, depending on the methods of processing. The beans must be spread thinly on drying bed and turned regularly to ensure even drying and prevent mould or rotting. 

 

green house

The photo shows how farmers in Ranau, Sabah dries all the coffee beans in handmade greenhouse and raised beds. This not only slows down the drying process, but it also gives protection from rain & wind 🌧

There are also mechanical drying with large dryer like pulped natural process. Due to the extreme large production in Brazil, mechanical drying is the only way to cope during harvest season. 

The duration of drying directly affects the shelf life of coffee beans. Research suggests that slow drying (ideally in greenhouse & raised beds) best retain the good flavours of coffee in green raw beans form.

 

Beans in parchment spread thinly on raised bed.

Cup of Excellence (COE) or higher priced coffees like gesha and rare varietals, these coffees are definitely slow dried in a greenhouse to best preserve the aromatics. This best practice helps to farmers to sell at a better price, as more people appreciate the good work of coffee farmers in todays world.

The top grade best in the world coffees can taste as good even after 6-7 weeks past roast date, some even still taste fantastic after 2 months or more with proper storage! 😍

These slow dried green beans can remain in a good state for more than a year after harvest, some even up to 18-20 months with proper storage 🙌🏼

On the other hand, pulped natural coffees typically have a shorter shelf life. As the moisture of beans are force dried by heat, this damages the cells of beans and unable to retain aromatic for too long. Most Brazil coffees (especially the commercial grade) is best finish within 3-4 weeks after roast date. 

Check out all the slow dried Worlds Best Coffees here.

 

taiwan gesha

How to buy coffee beans based on Coffee Processing & Flavours 🧐

The type of Coffee Processing methods directly affect the aromatics and flavour profile of coffee. 

If you have been drinking lots of single origin coffees, you can roughly picture of how the coffee taste like by just checking on the processing method & varietals 😉

 

gesha washed coffee

If you like coffee with lots of fruity notes, you’ll notice that most natural processedcoffees have vibrant fruity sweetness & juicy characteristics, like berries, strawberry & mango juicy notes you can find in Ethiopian natural coffees.

As for washed coffees, it’s common to find subtle fruit characteristics like peach, nectarine or apple notes, sometimes with some floral qualities like lavender and jasmine in Kenyan washed coffees. 

 

brazil pulped natural coffee

You can find lots of chocolate dominant flavour profile in pulped natural Brazils or Indonesian giling basah coffees that pairs very well with milk. That’s why you’ll find these coffees are commonly seen in espresso blends 😋

If you are big fan of super intense fruity and sweet coffee, Anaerobic coffees is the one to go for! 🙌🏼

 

anaerobic coffee

Of course, the roast level will also affect the flavour profile of coffee. Darker roast coffees will have more pronounce chocolate note and more subtle fruity floral notes.

That’s why high quality single origins are all light & medium roast to best preserve the beautiful fruity floral aromatics 😍 

To make it easy for everyone to find coffee beans in store, you can filter the coffee selections by Coffee Processing right at the bottom of sidebar (or topbar on mobile), check out all the coffees here.

 

blaq coffee

Like many coffee professionals, we have been tasting so many different coffee that we can tell which processing it is by just tasting it!

It takes a lot of practice and lots of variety of coffee tasting to train your palate, but eventually you'll get to identify the unique flavours of each processing. 

The best way to tell is to try out the same coffee with different processing methods, there you’ll easily notice the difference of the flavour profile from coffee processing.

For that, our Blaq Coffee tasting subscription box is the best way for you to explore variety of coffee processing at once. We pick a range of coffees with different flavour profile and processing every month. Of course, it's freshly roasted & delivered to your door, once a month. Check out the Blaq Coffee tasting box here.

Now that you know more about coffee processing, make sure that you check on it when you purchase coffee beans. Happy tasting!



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