Process
What happens between the ripe cherry and export-ready green coffee: the methods, each step in order, and the science behind them.
Methods
8 entries · 3 coming- MethodWashed processA processing method in which the skin, pulp and mucilage are removed from the coffee seed before it is dried.Source-checked
- MethodNatural processA processing method in which the whole coffee cherry is dried with its skin and pulp on, and the dried fruit is removed afterwards.Source-checked
- MethodHoney processA processing method in which the skin and pulp are removed and the seed is dried with part or all of its mucilage still on – between washed and natural coffee.Source-checked
- MethodPulped naturalA Brazilian semi-dry method, cereja descascado (CD), in which ripe cherries are pulped and the parchment is dried with its mucilage still on, without fermentation or washing.Source-checked
- MethodWet-hulled (giling basah)An Indonesian process in which pulped, briefly fermented parchment is hulled while still wet, at roughly 35–50% moisture content, and the naked green bean is then dried.Source-checked
- Method · comingDouble soaking
- MethodAnaerobic fermentationFermenting whole cherries or pulped coffee in closed, oxygen-poor vessels before drying. It changes the acids, alcohols and aroma of the coffee, and it carries its own risks for the seed and the cup.Source-checked
- MethodCarbonic macerationA winemaking method in which intact grapes ferment under carbon dioxide, borrowed by coffee for whole cherries sealed with the gas – what the name means in each field and what the thin coffee research shows.Source-checked
- MethodStarter cultures and co-fermentationSteering coffee fermentation by adding selected yeasts or bacteria, or by fermenting the coffee with fruit, spices or other ingredients – how strains are chosen, what trials found, and what competition rules allow.Source-checked
- Method · comingMonsooned coffee
- Method · comingAnimal-processed coffee
Steps, in order
From the tree to the export bag- 1Harvesting and cherry sortingfrom FarmHow coffee cherries are picked – by hand, by stripping or by machine – how ripeness is judged, how fast the fruit must reach the mill, and how cherries are sorted before processing.Source-checked
- 2PulpingThe first step of wet processing – a machine squeezes the seeds out of the fresh cherry and strips off the skin and pulp, leaving the seeds in their mucilage and parchment.Source-checked
- 3Mechanical demucilagingRemoving the mucilage from pulped coffee by mechanical agitation in a machine instead of by fermentation – fast, low in water, and at the heart of Colombia's ecological wet milling.Source-checked
- 4FermentationThe processing step in which yeasts and bacteria break down the mucilage and sugars around the coffee seed – how it runs, how to monitor it, when to stop it and what it does to the cup.Source-checked
- 5DryingThe post-harvest step that lowers the moisture of coffee – as parchment, whole cherry or honey coffee – to a level safe for storage, in the sun, in solar dryers or in mechanical dryers.Source-checked
- 6Resting (reposo)The holding period of dried parchment or dried cherry before dry milling, used to even out moisture across the lot; what storage conditions it needs, what happens in the seed, and what the storage literature shows.Source-checked
- 7Hulling and dry millingThe dry-mill steps that turn dried parchment or dried cherry into export-ready green coffee – hulling, polishing, grading, sorting and bagging.Source-checked
- 8Grading and sorting of green coffeeHow green coffee is separated by bean size, density and colour, and how defects are counted to give a lot its grade – screens in 64ths of an inch, gravity tables, optical sorters and defect equivalents.Source-checked
Science
The material and microbiology behind every method- ScienceMucilageThe sticky, pectin-rich inner layer of the coffee fruit that clings to the parchment – removed in washed coffee, kept in honey and pulped-natural coffee, and the main food for fermentation.Source-checked
- ScienceMicroorganisms in coffee processingThe bacteria, yeasts and moulds that grow on coffee cherries and seeds after harvest, what each group does, and how processing method, place and starter cultures shape them.Source-checked
- ScienceMoisture and water activityHow much water a coffee seed holds (moisture content) and how freely that water can act (water activity) – the two numbers that decide when coffee is dry, safe from mould and stable in storage.Source-checked
- ScienceThe living seed during processingThe coffee seed is still alive when it is picked. Processing switches on germination and drought-stress metabolism inside it, and heat or storage can kill it – changes that leave traces in green coffee chemistry and quality.Source-checked
- ScienceCherry-to-green conversionHow much green coffee a harvest gives – the mass lost at each step from fresh cherry to green coffee, the moisture behind it, and the conversion factors producers and traders use to calculate it.Source-checked
- Science · comingProcessing and flavour chemistry
Equipment
1 entryQuality
Defects, their causes and how to prevent them- QualityGreen coffee defects and their causesWhere each physical defect in green coffee comes from – the field, the wet mill, drying, the dry mill or storage – what it looks like, how it can change the cup, and how producers and mills prevent it.Source-checked
- Quality · comingScreen size
- QualityOchratoxin AOchratoxin A (OTA) is a mould toxin that can form in coffee on the farm, during drying and in storage. This entry covers the moulds that make it, where it forms, how roasting and brewing change it, how it is tested and the EU limits.Source-checked
- QualityGreen coffee storage and transportHow green coffee is kept and shipped between the dry mill and the roaster – warehouse, bag and container – and why warm, humid air and time make it age.Source-checked
By-products and environment
3 coming- By-product · comingWet-mill wastewater
- By-product · comingCoffee pulp and compost
- By-product · comingCascara
See also: Coffee cherry anatomy (plant)