Processing and fermentation

The processing and fermentation questions of this silo, each paired with a short answer. Click for the full entry. 32 questions.

• What is anaerobic fermentation in coffee?

  Anaerobic fermentation is a post-harvest technique in which cherries or demucilaged beans are sealed in oxygen-free tanks for 24 to 120 hours. The absence of air shifts the microbial community toward

• How do you prevent fermentation defects in coffee processing?

  Fermentation defects in coffee, vinegary, putrid or undesirable alcohol notes, result from excessive duration, uncontrolled temperature or bacterial contamination. Preventing them requires active mo

• What is carbonic maceration in coffee?

  Carbonic maceration is a form of anaerobic fermentation borrowed directly from Beaujolais winemaking: whole coffee cherries are placed in a tank saturated with CO2, which triggers intracellular fermen

• Difference between carbonic and strict anaerobic fermentation?

  Carbonic maceration and strict anaerobic fermentation are both oxygen-free processing protocols, but their mechanisms and sensory profiles differ considerably. Carbonic maceration actively injects CO₂

• What defines a clean natural coffee?

  A well-executed natural, often called a 'clean natural' in specialty jargon, delivers a vibrant, well-defined fruit profile without the heavy fermented defects that plague poorly managed naturals. Y

• What is coffee drying?

  Drying is the stage that brings coffee moisture from 55-60 % (post-fermentation or cherry exit) down to 10-12 % (market target), a prerequisite for storage and export. Depending on the method, concre

• What is an experimental process coffee and how does it differ from classic processes?

  An experimental process coffee refers to any post-harvest treatment that departs from washed, natural or honey conventions by introducing deliberately controlled variables: inoculation of specific yea

• What is fermentation with additions (koji, wine, beer) in coffee and what profiles does it create?

  Fermentation with additions involves deliberately introducing living organisms or organic substrates, winemaking yeasts, beer lees, sake must, koji spores (Aspergillus oryzae) or fruit juices, into

• What is controlled vs wild fermentation in coffee?

  Wild (or spontaneous) fermentation is driven by the micro-organisms naturally present on cherries and in the post-harvest station environment, without producer intervention. Controlled fermentation in

• What is double fermentation process in coffee?

  Double fermentation process is a post-harvest method in which coffee undergoes two distinct, sequential fermentation phases. The first phase is typically conducted on whole cherries (with mucilage and

• What is honey process coffee?

  The honey process, also called pulped natural, is a hybrid between washed and natural: the cherry is depulped, but part of the sticky sweet mucilage is kept on the bean during drying. The result sit

• How does coffee fermentation work?

  Coffee fermentation is the biochemical phase during which microorganisms, mainly yeasts (Saccharomyces, Pichia) and bacteria (Lactobacillus, Leuconostoc, Acetobacter), break down sugars and pectin i

• How does the processing method influence the perceived acidity of a coffee?

  Post-harvest processing is one of the most determining factors of perceived acidity in the cup, sometimes more so than origin or altitude. A washed coffee retains the full purity of the bean's natura

• What is a hybrid washed-anaerobic process?

  A hybrid washed-anaerobic process is a coffee processing method that combines the mechanical depulping of a washed coffee with an anaerobic fermentation stage in a sealed tank before the final washing

• What is Indian monsooning of coffee and how does this process create a unique profile?

  Monsooning is a traditional Indian process involving the exposure of parchment coffee to moisture-laden monsoon winds from June to September in coastal warehouses in Kerala or Karnataka. The beans swe

• What is lactic fermentation in coffee?

  Lactic fermentation in coffee is a post-harvest process in which lactic acid bacteria (Lactobacillus spp., Leuconostoc spp.) break down sugars in the coffee mucilage into lactic acid, under anaerobic

• What is mechanical drying of coffee and what are its impacts on quality?

  Mechanical drying uses heated rotating drums, called guardiolas, or forced-air dryers to reduce the moisture content of parchment or cherry coffee to 10-12% within hours. Unlike solar drying on rais

• What is the target moisture content for green coffee?

  The target moisture content for commercially acceptable green coffee is 10 to 12 %, with an industrial sweet spot at 11 ± 0.5 %. Below 9 %, the bean turns brittle, loses aromatics and drifts toward a

• What is the natural coffee process?

  The natural process, also called dry process, dries whole coffee cherries with their pulp and mucilage still attached over two to four weeks. As the fruit slowly dehydrates, the bean absorbs sugars

• What is Nordic Approach fermentation?

  Nordic Approach is a specialty coffee import company based in Oslo, Norway, founded in 2011, which has developed a systematised approach to working with producers to standardise and document fermentat

• What is pulped natural processing?

  Pulped natural (also called honey process in Central America, or semi-washed) is an intermediate processing method between washed and natural. After picking, the outer pulp is mechanically removed (de

• What is the difference between raised beds and patio drying?

  Raised beds (African beds) are elevated drying structures 80-120 cm off the ground, made of mesh or netting, that allow air circulation under and around cherries or parchment. Patio drying uses flat c

• What is semi-washed processing?

  Semi-washed, also called pulped natural or in Brazil cereja descascado, is a hybrid process where the cherry is mechanically depulped but the bean is laid out to dry with part of the mucilage still

• What is the Swiss Water decaffeination process?

  The Swiss Water Process is a 100 % chemical-solvent-free decaffeination method developed commercially in Canada during the 1980s. It uses water pre-loaded with the soluble compounds of coffee, called

• What is the target pH during coffee fermentation?

  In coffee fermentation, pH is the primary indicator of process progress and microbial health. A target pH of 3.8 to 4.5 is generally sought for washed fermentations: below 3.5, the risk of over-fermen

• What is the thermal shock process?

  The thermal shock process is an experimental post-harvest coffee technique in which freshly picked cherries are subjected to rapid alternations between high and low temperatures (typically 60-80 °C th

• What is the washed coffee process?

  The washed process, also called wet processing, is a post-harvest method that mechanically removes the cherry's pulp, ferments off the sticky mucilage around the bean, then rinses and dries the coff

• What is the difference between washed and natural coffee?

  Washed and natural are the two long-standing post-harvest routes. The washed process depulps the cherry, ferments the mucilage off the bean, then washes and dries it, yielding a clean, bright cup. The

• What is wet-hulled or giling basah?

  Wet-hulled, in Indonesian giling basah, is a processing method specific to Sumatra, Sulawesi and parts of Flores, where the coffee is hulled at high moisture (30-40 %) instead of the usual 10-12 %.

• Why does processing affect coffee flavor?

  Processing, the post-harvest path from cherry to green bean, shapes coffee flavour because it controls three decisive variables: how much fruit sugar and aromatic compound the bean absorbs, which mi

• What is yeast inoculation in coffee?

  Yeast inoculation in coffee means intentionally adding selected yeast strains (primarily Saccharomyces cerevisiae and its variants, as well as other genera such as Pichia or Torulaspora) to the fermen

• What is the difference between yellow, red and black honey processes?

  Yellow, red and black honey describe three intensities of the same process: the higher the mucilage percentage left on the bean (yellow 25-50 %, red 50-90 %, black 90-100 %), the slower the drying and

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