The washed process is by far one of the most popular in specialty coffee. By removing all the fruit, skin, and mucilage from the beans, coffee tastes much cleaner and brighter – two attributes of many which both coffee professionals and consumers favour.

Despite its positive impact on coffee flavour and quality, however, the washed process is not without its limitations and challenges. One of the biggest that has been discussed for years now is the large amount of water required to carry out this process – which some producers already have little access to.

At the same time, coffee farmers have started to adapt to the ongoing effects of climate change. Depending on their geographical location, this could mean increased or reduced access to water sources. In turn, this could ultimately force them to “redefine” washed processing methods or find alternatives altogether.

To learn more, I spoke to Régine Léonie Guion-Firmin, a coffee quality expert, and George Ngure, a coffee specialist and washing station manager.

You may also like our article exploring trends in experimental coffee processing.

The washed process: A breakdown

Now more than ever, specialty coffee producers use many different processing methods. But no matter which ones they choose, the overall goal is to improve coffee quality and develop specific flavour profiles.

Alongside a growing number of experimental and advanced processing methods, there are also more traditional techniques. These are:

• Natural – the cherries are fully intact while drying (including skin and mucilage)
• Pulped natural – producers remove the outer skin and some mucilage from the cherries before drying
• Honey – various levels of mucilage are left on the cherries as they dry
  • Black: most similar to natural processing, with almost all mucilage left intact
  • Red: less mucilage left on cherries
  • Yellow: producers remove more mucilage compared to black and red honeys
  • White: similar to washed processing, when most mucilage is removed

In addition to these processing techniques, the washed process is one of the most popular in the coffee industry. Also known as wet processing, this method involves removing the fruit of the cherry, including the skin and pulp. This leaves only the parchment and silverskin on the beans.

The pulped coffee is then placed in water tanks, which helps to loosen any remaining mucilage. Here it technically ferments, but it’s not to be confused with intentional and controlled fermentation processing methods.

Following this, the wet parchment travels through washing channels. Running water and brushes push the coffee through the channels, while it’s also pre-graded according to density. In some cases, washed coffee is also soaked overnight to fully remove all mucilage. We refer to this as fully-washed coffee.

The final step of the process involves drying parchment coffee on raised beds before it is milled and ready for export.

Why is it so popular?

In certain producing countries, many farmers favour washed processing methods. One of the most notable is Kenya, which is largely down to the country’s colonial history.

Régine is also an authorised SCA trainer in Kenya. 

“Essentially, British colonial powers wanted to sell coffee on the market faster,” she says. This is because it is easier and quicker to dry washed coffees compared to other processing methods as you remove all the mucilage.

“Additionally, many people used to believe that natural processing was ‘bad’,” she adds – a statement which has of course now been widely disproved.

Across the global coffee industry, the washed process has become so popular because of the highly desirable sensory profile it tends to result in. Most washed coffees are well-balanced and bright with a very clean finish – and generally considered a “true expression” of terroir.

That doesn’t mean, however, that this process isn’t without its significant challenges.

“The washed process is expensive to carry out,” Régine says. “Drought or no drought, it’s expensive for producers.”

George manages a coffee factory (or wet mill) in Kenya.

“We were paying monthly water bills of up to 500,000 Kenyan shillings just for pulping and washing the coffee,” he says. “In that regard, we would rather switch to natural processing.”

This is because the washed processing method uses high volumes of water at almost every stage of the process. From pouring the cherries into the pulping machine to placing pulped cherries in fermentation tanks to transporting wet parchment coffee through washing channels, producers need access to a lot of water.

“And afterwards, you have to recycle the used water because you can’t put it back in rivers or lakes,” Régine adds. “The water is too acidic, so you would destroy wildlife and the ecosystem.”

Considering the impact of climate change

The amount of water needed for the washed process is huge. For a long time, rivers have been the main sources of water, which is why many wet mills are built close to them. Over the past decade, however, many rivers around the world have been gradually drying up due to the ongoing effects of climate change.

This has left wet mill workers with little choice but to find alternative water sources. One option is to dig boreholes, which are narrow shafts drilled into the ground either vertically or horizontally. But for many producers and co-operatives, this is an expensive practice – not to mention that the water extracted from boreholes must be purified, which only adds to costs.

With dwindling water supplies, more farmers have started to use other processing methods which use less water – especially the natural process.

“I don’t need to employ as many people to dry cherries, as opposed to pulping, washing, and then drying,” George says.

He adds that a growing number of traders and roasters who buy Kenyan coffee are also starting to see more value in other processing techniques.

“We used to sell a honey processed coffee called Kaldi City Roast for US $24 per retail bag, whereas our washed coffee sold for US $16,” he explains. “What’s more, we didn’t require extra workers to wash and pre-grade the honey processed coffee, which helped reduce costs.”

The future of the washed process

We can safely assume that the washed processing method will never go out of style. However, with sustainability increasingly at the forefront of issues in the coffee industry, it’s clear that more producers are also looking for alternative ways to process their coffees.

And in countries like Kenya – where the washed process has been so popular for so long – this is particularly groundbreaking.

“Most of our customers who previously bought washed coffee switched to honey processed and natural coffees when we introduced them, regardless of the price,” George explains. “We were amazed at how the less labour-intensive coffees were fetching higher prices.”

Régine agrees that farmers and co-operatives should be open to exploring other processing methods.

“Times change and producers need to see beyond that,” she says. “They should try using different processing methods – honey, natural, anaerobic fermentation, carbonic maceration, and more.

“And if buyers can’t come to us, we go to them through Instagram, Facebook and other social media channels,” she adds. “Very few farmers even have a Facebook page! It’s time for them to utilise social media to their advantage.”

Supporting producers with their decisions

No matter which processing methods producers use, they should always receive the right level of support from other industry stakeholders. But for some smallholders, diversifying processing techniques could be integral to improving sustainable practices – and potentially receiving higher prices.

In line with this, more formal training and educational opportunities on how to carry out different processing methods are essential, or producers could risk reducing coffee quality. In the context of Kenya, however, many co-operative members and managers still don’t have enough access to information about how to successfully implement techniques other than the washed process.

“You can carry out more variations of the natural process, such as anaerobic fermentation or carbonic maceration, so why not do it?” Régine asks. “In Kenya, we tend to think washed processing is good, while natural processed coffee is Mbuni – which is a negative term in Swahili. But this attitude needs to change.”

The washed process will forever be one of the most popular in specialty coffee – revered for the bright, clean flavour profiles it produces.

However, with the impact of climate change forcing farmers to adapt to new and existing challenges, we could see some of them opt for processing methods which have less of an environmental footprint.

Enjoyed this? Then read our article on how experimental coffee processing techniques can help producers overcome challenges.

Perfect Daily Grind

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