Continuing on in a little series I have been trying to compile throughout this blog, called a spotlight on processing. My aim here is to shed some light on different processing methods, explain their characteristics and some pros/cons of each method. Leaving you, the coffee lover with a little bit more knowledge when you select the coffee's you drink.
So far we have already covered Giling Basah/ Wet Hulled and Dry/Natural process. Click the links if you missed out on these interesting methods.
What is washed process?
Washed process, fully washed, wet processed. These are different terms you may see on a coffee bag. Here's a secret, they all mean the same thing, and are describing how the bean was processed. In other words what method was used to remove the pulp, mucilage, parchment and silver skin that covers those little seeds we call coffee beans.
The method used to do this impacts the final flavours in the cup of coffee you consume, this is why it is vital to know a little bit about processing and also why you will often find this information prominently placed on a coffee label.
Washed process coffees are revered around the world for their quality, are a favourite among speciality roasters, baristas and consumers alike, prized for clarity, complexity and acidity.
These clean, complex flavours that are considered the natural characteristics of the bean (seed) it's self, are less effected by the other parts of the coffee cherry, because they are removed early in the drying phase, unlike natural/dry process.
A washed coffee is a coffee that has had its pulp and mucilage removed before the drying phase begins, leaving only the parchment and silver skin intact with the bean.
Step by step.
- Harvesting: Like with all coffees, the cherry's are harvested from the coffee trees.
- Sorting: The cherries are placed in water, the best cherries will sink as they are denser than water while any unripe or defective cherries will float to the top. The floating cherries are removed and sold as lower quality coffees.
- Pulping: Removal of the pulp (skin) of the coffee cherry is carried out using a machine called a depulper. This machine basically squeezes the fruit seperating the seed, parchment and mucilage away from the outer layer. In quality coffees this will be done within the first 8 hours of harvesting, leaving it for even one day will start to impart undersired flavour into the final cup. In high quality operations, the coffee is usually passed through a sieve or coffee screen to remove any excess husk or cherries where adiqate pulping didn't occur in the machine.
- Fermentation: This will vary depending on regions but the principle is the same. Allowing the microorganisms to break down the sticky mucilage so that it is easier to remove. The process normally takes around 24hrs but will depend on temperature, humidity and volume of coffee. This is usually carried out in big tanks, where the coffee is kept until sufficient fermentation has occured allowing the mucilage to be washed off the beans. While washing the mucilage off the coffee, it also allows another chance to sort any beans that float indicating defects.
- Drying: The final stage of this processing method is the drying stage. Care and attention must be paid throughout this stage regardless of drying using the sun, or a mechanical dryer. The beans are extremely susceptible to microorganisms or physical deterioration/damage at this point. Beans must be raked several times a day to ensure drying occurs evenly. This process continues until a desired moisture content of around 11% is achieved. This usually takes 1-2 weeks and will depend on the climate at the time of drying. Mechanical dryers can also be used or a mixture of both.
The beans are then transported to mills, where when they are milled/dry hulled, removing the parchment and ready to be sold.
Pros
- Washed coffees are prized globally for their clarity and acidity.
- Generally fetch higher prices when sold. compared to naturals or semi washed coffee.
- More consistency and control over the end flavour in the cup.
- Results in a complex cup.
- Cuts drying time down to almost half.
- Less risk of beans spoiling from an adverse fermentation.
- Allow farmers to control the fermentation, creating new and unique flavours and opening up avenues to unique processing methods.
Cons
- Uses large amounts of water, which can be scarce and valuable in a lot of coffee growing regions.
- Produces large amounts of coffee waste water, which if not treated properly is damaging to local waterways and soils. If not treated properly it can cause detrimental effect to future crops as well as other impacts for local communities.
- Produces large amounts of solid waste from the coffee cherries. However, if treated correctly this can also become an organic fertilizer to be used as a benifit for future crops.
Conclusion
If your tastes prize clarity and acidity, over deeper sweet jammie flavours, then chances are washed coffee is for you.
Personally I gravitate towards washed coffees for lighter roasts and filter coffee. If I'm planning on basing something around milk based beverages, I tend to lend myself toward the naturals. For me washed coffees can be lost in milk, however are perfect for black coffee. Don't forget, every rule has its exceptions, and those above comments have many.
The best part about the world of coffee is the variety, so get out there and try different processing methods to see what flavours you lean towards. Try them as espresso, filter, milk based, cold and hot. Then you can experience the difference for yourself.
Lars x
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