Ever spotted the word “natural” or “washed” on coffee packaging and wondered what it means? James Hanson explains all.
Coffee is surrounded by specifics: varietals, roasting profiles, brew times and so on. The term “processing”, on the other hand, is about as vague as it gets, which is perhaps odd considering the myriad elements it can involve.
In essence, processing is the journey from coffee cherry to green bean. It’s during processing that producers have the opportunity to experiment with flavour and potentially respond to market demand.
The three most common methods are natural, pulped natural (or honey) and washed. These are still broad strokes, however, as the specifics vary according to terroir, economic geography, cost and tradition, as well as the farming model.
The natural process involves drying ripe cherries in the sun. Once the bean inside has a 10-12% moisture content, the cherries are hulled and the beans sorted, graded for quality and bagged.
While sun drying is the most accessible method, owing to low set-up costs and water usage, it’s also the riskiest if quality-control methods are not applied. It’s not suited to countries with high levels of rainfall. If the cherries aren’t turned frequently, fermentation — and flavour — will be inconsistent.
Natural processing is most common in dry climates, particularly Ethiopia. Increasingly, however, it’s an option for farmers with the freedom and cashflow to process coffee in multiple ways.
With washed coffees, the cherries are first pulped by mechanical rollers, removing the outer skin. The beans and remaining mucilage are then placed in fermentation tanks for eight to 50 hours, during which time the mucilage breaks down, influencing the winey acidity and fruity character found in the best washed coffees. The beans are then washed, dried and hulled.
There are ecological concerns about this method, as coffee wastewater is a pollutant. Some farms use mechanical scrubbers, but this is dependent on the farm’s financial stability.
Pulped Natural Processing
During pulped natural, or honey, processing, the cherries are pulped as with washed, but on a spectrum. Black honey sees 100% of mucilage left on, white honey just a trace, with red, orange and yellow sitting in between.
Recent years have seen an increase in experimental processing. Some of this is farmer innovation — like swapping concrete fermentation tanks for stainless steel. But new processes are also tried on microlots, often for competition, and include freezing coffee and using anaerobic or carbonic maceration as in wine production.
While these innovations can lead to short bursts of fame for the farm, they can also come at the cost of sustainability. To safeguard the farmers’ interests, roasters can commit to buying experimental lots regardless of outcome and farmers can collaborate to harness each other’s expertise.
A complicated but necessary subject, processing is defined by context, tradition, and innovation. It’s much more than a word on a bag.