February 18, 2016

Processing Improvements: The Key to Specialty Grade Naturals


Natural coffees may be one of the oldest forms around, yet it’s only in the last couple of years that they’ve been able to enter the specialty coffee market. The trend is growing fast, with an impact on origin; traditional producers of naturals, such as Brazil, are working towards a continuous improvement of their post-harvest process while traditionally washed-coffee producing countries have begun branching out.

This is a welcome move: specialty-level naturals can have an excellent combination of flavor complexity and a full body, leaving them able to satisfy the most demanding of palates.

SEE ALSO: Controlled Fermentation: A Critical Step in Flavour Development?

Yet nothing happens for a reason. Read on to find out what makes naturals different – and the reason for their sudden rise in Third Wave coffee.

Natural Process

Natural processing: a traditional but impressive method. Credit: BSCA

Naturals: What’s so Different about Them?

Natural (or dry) processing is the easiest way to transform coffee cherries into green beans, yet it’s also one of the most difficult ways to produce good coffee.

It’s always been a cheap, simple processing method: all you need is sunlight and a flat surface. After the cherries have been harvested, they’re sun-dried until their moisture content drops to 11-12%. There are different techniques for revolving the cherries, and there are also some different drying methods: some farmers use raised beds, others dry the coffee on patio pavements, and others still combine these methods with mechanical dryers. Yet regardless of these variations, natural processing doesn’t require any fancy equipment.

coffee farm

Will the fruit of this farm become a natural-processed coffee? Credit: BSCA

It is, however, highly dependent on weather conditions. After all, they are sun-dried. And if a lack of sunshine means it takes too long for the cherries to dry, there’s a risk of fermentation.

This is why water-linked processing methods have become popular, from pulped natural to honey to fully washed. By removing the outer layers of the cherry, they speed up the drying process and so reduce the risk of fermentation.

There’s still a lot more to discover about the effects of each processing method but, broadly speaking, naturals tend to have higher body, less acidity, and a wider spectrum of fruity notes compared to washed coffees. On the other hand, naturals tend to score lower in terms of the cleanliness of the cup. They are also more vulnerable to damage, given the longer periods of exposure to external agents; this is why they are rarer to find in specialty coffee.

Coffee cupping

Natural coffees: you can taste the difference in the cup. Credit: @timjcoffee

Processing: The Key to Specialty- Grade Naturals

Specialty-grade coffee producers often shied away from natural processing. They knew that temperature and humidity levels, so unreliable and so difficult to predict, would have a major impact on the quality of their beans. As of such, naturals often came from producers who were less committed to quality, who lacked the resources to invest in post-harvest infrastructure, or whose home regions were blessed with less rain during the harvest period (particularly Ethiopia, Indonesia, Yemen, and Brazil).

However, scientific research is changing this. Especially in Brazil, high-quality naturals are grown in lots specifically designed to enhance the coffee’s scoring ability, and extensive attention is paid during the post-harvest operations. In particular, the use of African beds and greenhouse patios, teams of selective pickers working in periods or parcels, and cherry color sorting machines help to ensure the best quality.

natural process

Natural processing: making use of the sun’s heat. Credit: BSCA

Another crucial step is separating fruit at different maturation stages. Under- or overripe cherries can seriously impact on the taste of the final product. This used to be an area where wet-processing methods were a clear winner, since water provides a mean for density separation and the pulpers could be set to pulp only ripe cherries.

However, new technology has significantly narrowed this gap. In the fields, mechanical harvesters can be adjusted to pick mainly mature fruits that are more loosely attached to the coffee plant, just by vibration set-up. Similarly, growers may choose to harvest one side of the coffee row at a time, based on sun exposure and quicker fruit maturation. And new generation color sorters, which can identify and separate ripe yellow and red cherries from the unripe green ones, are now available.  

In other words, hello specialty-grade naturals.

Written in collaboration with Fabrício Andrade (Fazenda Samambaia) and edited by T. Newton.

Feature Photo Credit: @timjcoffee

Perfect Daily Grind.