Natural Process Robusta: What Buyers Should Know

Natural process — also called dry process — is the oldest way to prepare coffee and the most common method for Robusta in Indonesia. If you buy Robusta green coffee, understanding it helps you judge a lot before the sample arrives.

What is natural process?

In the natural process the whole coffee cherry is dried with the fruit still on the bean. Nothing is washed off and no pulp is removed beforehand. Once dry, the dried fruit and the parchment layer are removed in a hulling step, leaving the green bean that is then sorted, graded and bagged for export.

How natural Robusta is made

1. Harvest and sorting. Ripe cherries are picked and sorted to remove unripe, overripe and damaged fruit.
2. Drying. Cherries are spread in thin layers — on raised beds, tarps or clean drying floors — and turned regularly. Drying typically takes a few weeks, depending on weather and layer thickness, until the beans reach the target moisture.
3. Resting and hulling. The dried cherries are rested, then hulled to release the green bean.
4. Sorting and grading. Beans are sorted by size and by defects; under the SNI standard, defects are counted per 300 g to give the grade.
5. Packing. The coffee is bagged — in our case in a GrainPro inner bag inside a 60 kg jute sack.

Cherries drying on raised beds.

What natural process does to the cup

Because the bean dries inside the fruit, natural lots tend to show a fuller body, lower perceived acidity and a fruit-forward sweetness. In Robusta this can soften bitterness and add ripe fruit notes to the chocolate and nut character the species is known for. Our Temanggung Natural Fine Robusta cups with dark chocolate, ripe stone fruit and tobacco leaf, a full body and a clean finish.

What can go wrong

Natural process is unforgiving. The fruit that gives sweetness also feeds microbes if drying is slow or interrupted. The usual problems are:

• Uneven drying, leaving beans in one lot at different moisture levels
• Rain re-wetting the cherries, which leads to mould and fermentation
• Over-fermentation, giving sour, vinegary or musty cups
• Thick layers that dry too slowly
• Contamination from dust, soil or poor drying surfaces

These show up as defects. Under SNI, black, sour or fermented and mouldy beans are primary defects with the heaviest weighting — see our grading guide.

What to check when buying natural Robusta

• The moisture reading (the SNI maximum is 12.5%) and how it was measured
• The defect count per 300 g and the SNI grade it corresponds to
• The smell and look of the sample: clean, with no mould or sour, fermented odour
• Colour and size uniformity across the sample
• The drying method, and how the lot was protected from rain
• A cupping of the sample — ideally confirmed against a pre-shipment sample of the lot you will receive
• Which processor produced the lot

Why we offer natural process only

All the lots we offer are natural process because that is what our processing partners in Temanggung run today — and we would rather sell one process well, with documentation, than promise several we cannot back up. The range runs from selected Fine Robusta to SNI Grade 4b; see Our Coffee.