{ "id": "coffee-cherry-anatomy", "url": "https://coffearium.org/entries/coffee-cherry-anatomy/", "license": "CC-BY-4.0", "title": "Coffee cherry anatomy", "summary": "The layers of the coffee fruit, from the outer skin to the seed, and why each one matters for processing.", "domain": "post-harvest-processing", "kind": "Concept", "stage": "plant", "topics": [ "science" ], "topicSections": {}, "lang": "en", "status": "verified", "reviewer": "Coffearium verification pass", "lastVerified": "2026-10-08T00:00:00.000Z", "updated": "2026-10-08T00:00:00.000Z", "brief": [ "A coffee cherry usually holds two seeds, wrapped in several layers – skin, pulp, mucilage, parchment and silverskin.1,2", "Processing methods differ mainly in how these layers are handled – whether the fruit is removed before drying or dried on the seed.3", "The removed layers – husk or cascara, mucilage, parchment and silverskin – are the main by-products of coffee processing.1" ], "quickFacts": [ { "label": "Fruit type", "value": "Drupe, about 1.5 cm across" }, { "label": "Seeds per cherry", "value": "Usually two" }, { "label": "Layers (outside in)", "value": "Skin, pulp, mucilage, parchment, silverskin, seed" }, { "label": "Pulp share", "value": "About 30% of the cherry's dry matter" }, { "label": "Ripe skin colour", "value": "Usually red; orange or yellow in some genotypes" } ], "aka": [ "Coffee fruit", "Coffee berry" ], "linkTerms": [ "coffee cherry", "coffee cherries", "exocarp", "mesocarp", "endocarp" ], "related": [ "washed-process", "natural-process", "mucilage", "seed-anatomy-and-storage", "fruit-development", "germination-and-seedlings", "cherry-to-green-conversion", "seed-physiology" ], "contested": [ "Mucilage composition: Cenicafé reports 15% solids, of which 80% are pectic acids and 20% sugars7; compilations cited in a 2018 study give 85–91% water and 6.2–7.4% sugars, or 84.2% water, 4.1% sugar and 0.91% pectin5; a 2022 review gives 91.77% moisture, 6.43% total sugars and 0.81% pectins.8 The sources differ most on pectin: the bulk of the solids in Cenicafé, under 1% of the mucilage in the other two." ], "corrections": [], "sources": [ { "id": "s1", "title": "Comparative Analysis of Selected Chemical Parameters of Coffea arabica, from Cascara to Silverskin", "authors": "Bobková, A.; Poláková, K.; Demianová, A.; Belej, Ľ.; Bobko, M.; Jurčaga, L.; Gálik, B.; Novotná, I.; Iriondo-DeHond, A.; del Castillo, M. D.", "year": 2022, "publisher": "Foods 11(8), 1082", "url": "https://www.mdpi.com/2304-8158/11/8/1082", "doi": "10.3390/foods11081082", "tier": "A", "quote": "A coffee cherry consists of the outer skin, usually green in unripe fruit and red (some particular genotypes can be orange or yellow) in ripe fruit, which covers a soft and sweet flesh, following the highly hydrated layer of mucus (pectin layer), a thin yellowish endocarp, parchment, and finally the Silverskin covering the green coffee beans.", "accessed": "2026-09-30T00:00:00.000Z" }, { "id": "s2", "title": "Coffee fermentation: Expedition from traditional to controlled process and perspectives for industrialization", "authors": "Elhalis, H.; Cox, J.; Zhao, J.", "year": 2023, "publisher": "Applied Food Research 3(1), 100253", "url": "https://www.sciencedirect.com/science/article/pii/S2772502222002086", "doi": "10.1016/j.afres.2022.100253", "tier": "A", "quote": "The main function of the fermentation is to remove the outside bean layers leaving two dried seeds.", "accessed": "2026-09-30T00:00:00.000Z" }, { "id": "s3", "title": "Code of Practice for the Prevention and Reduction of Ochratoxin A Contamination in Coffee (CAC/RCP 69-2009)", "authors": "Codex Alimentarius Commission (FAO/WHO)", "year": 2009, "publisher": "Codex Alimentarius", "url": "https://www.fao.org/input/download/standards/11250/CXP_069e.pdf", "tier": "A", "quote": "Dry process: treatment of coffee cherries consisting in drying them, either under sunlight or in drying machines, to give husk coffee. … Wet process: treatment of coffee cherries consisting of the mechanical removal of the exocarp (pulp) in the presence of water.", "accessed": "2026-09-30T00:00:00.000Z" }, { "id": "s4", "title": "Risk Assessment of Coffee Cherry (Cascara) Fruit Products for Flour Replacement and Other Alternative Food Uses", "authors": "Eckhardt, S.; Franke, H.; Schwarz, S.; Lachenmeier, D. W.", "year": 2022, "publisher": "Molecules 27(23), 8435", "url": "https://www.mdpi.com/1420-3049/27/23/8435", "doi": "10.3390/molecules27238435", "tier": "A", "quote": "About 30% of the dry matter of the coffee cherry is due to the exocarp and mesocarp, which together are generally referred to as pulp.", "accessed": "2026-09-30T00:00:00.000Z" }, { "id": "s5", "title": "Optimization and Scale-Up of Coffee Mucilage Fermentation for Ethanol Production", "authors": "Orrego, D.; Zapata-Zapata, A. D.; Kim, D.", "year": 2018, "publisher": "Energies 11(4), 786", "url": "https://www.mdpi.com/1996-1073/11/4/786", "doi": "10.3390/en11040786", "tier": "A", "quote": "it consists of 85–91% (w/w) water, 6.2–7.4% (w/w) sugars and small amounts of protein, non-reducing sugar, and pectin", "accessed": "2026-10-08T00:00:00.000Z" }, { "id": "s6", "title": "Transient occurrence of seed germination processes during coffee post-harvest treatment", "authors": "Bytof, G.; Knopp, S.-E.; Kramer, D.; Breitenstein, B.; Bergervoet, J. H. W.; Groot, S. P. C.; Selmar, D.", "year": 2007, "publisher": "Annals of Botany 100(1), 61–66", "url": "https://academic.oup.com/aob/article/100/1/61/2763338", "doi": "10.1093/aob/mcm068", "tier": "A", "quote": "The extent and the time courses of germination processes in coffee seeds differed significantly between wet and dry processed beans.", "accessed": "2026-09-30T00:00:00.000Z" }, { "id": "s7", "title": "Ecological Processing of Coffee at the Farm Level: An Ecological and Profitable Case", "authors": "Roa, G.; Oliveros, C. E.; Álvarez, J.; Sanz, J. R.; Ramírez, C. A.; Dávila, M. T.; Álvarez, J. R.; Zambrano, D. A.; Puerta, G. I.; Rodríguez, N.", "publisher": "Cenicafé (Colombian Coffee Research Centre)", "url": "https://www.ctahr.hawaii.edu/hawaii/downloads/Low_Water_use_processing.pdf", "tier": "A", "quote": "The mucilage of the coffee contains 15% of solids in the form of a water insoluble colloidal hydrogel, without cellular structure. The present solids in it contain 80% of peptic acids and 20% of sugars.", "accessed": "2026-10-08T00:00:00.000Z" }, { "id": "s8", "title": "Mejoramiento y uso de los efluentes para el beneficio del café [Improvement and Use of Effluents for the Benefit of Coffee]", "authors": "González-Freire, A.; Martínez-Hernández, C. M.", "year": 2022, "publisher": "Revista Ciencias Técnicas Agropecuarias 31(2)", "url": "https://revistas.unah.edu.cu/index.php/rcta/article/view/1602", "tier": "B", "quote": "El principal componente del mucílago de café es la humedad (91,77%), seguido de los azúcares totales (6,43%), las pectinas (0,81%) y el nitrógeno (0,12%).", "accessed": "2026-10-08T00:00:00.000Z" } ], "markdown": "## The layers, from outside in\n\n
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  1. Skin (exocarp): green while unripe, usually red when ripe; some genotypes ripen orange or yellow.1
    2. \n
  2. Pulp (mesocarp): the soft, sweet flesh under the skin.1,4
    3. \n
  3. Mucilage: a highly hydrated, pectin-rich layer that clings to the parchment.1,3
    4. \n
  4. Parchment (endocarp): the shell around each seed.3,4
    5. \n
  5. Silverskin: the innermost layer, directly covering the seed.1
    6. \n
  6. Seed: the green coffee bean. A cherry usually contains two.2
    7. \n
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A ripe cherry cut open lengthwise, the layers numbered from outside in. Point at a layer, its number or its name to highlight it. Schematic, not to scale.
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\n\n## Why it matters for processing\n\nThe main processing methods are defined by what happens to these layers:\n\n- In the **wet (washed) process**, the skin and pulp are removed mechanically in the presence of water.3 The mucilage left on the seeds is then removed, by fermentation or other methods, and washed off before drying.3 See [Washed process](/entries/washed-process/).\n- In the **dry (natural) process**, the whole cherry is dried, in the sun or in drying machines, giving \"husk coffee\".3 The dried husk – skin, pulp, mucilage and parchment – is removed afterwards, together with as much silverskin as possible.1 See [Natural process](/entries/natural-process/).\n\n## By-products\n\nCascara (the dried husk), mucilage, parchment, silverskin and, after brewing, spent coffee grounds are the main by-products of coffee.1\n\n\n\n
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A: the fruit. B: a seed from its flat side, with its central groove. The cherry cut open is the figure at the top of this entry. Schematic, not to scale.
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\n\n## Size and proportions\n\nThe coffee cherry is a drupe, about 1.5 cm across on average.4 Skin and pulp together make up about 30% of the cherry's dry matter.4 Dry processing gives roughly 1 kg of husk for every kilogram of coffee beans.4\n\n## Which layers leave when\n\n| Layer | Botanical name | Washed process | Natural process |\n|---|---|---|---|\n| Skin | Exocarp | Removed by the pulper, before drying | Dried on the seed, removed at hulling |\n| Pulp | Mesocarp | Removed by the pulper, before drying | Dried on the seed, removed at hulling |\n| Mucilage | – | Removed by fermentation or other methods, then washed off | Dried on the seed, removed at hulling |\n| Parchment | Endocarp | Dried on the seed, removed at hulling | Removed at hulling, with the husk |\n| Silverskin | – | Stays on the seed; detaches in roasting | As much as possible removed at hulling; the rest detaches in roasting |\n\nSources for the table: Codex code of practice3, Bobková et al.1, Eckhardt et al.4\n\n## Mucilage: what it is made of\n\nMucilage is mostly water. Figures compiled in a 2018 study give 85–91% water and 6.2–7.4% sugars, with small amounts of protein, non-reducing sugar and pectin.5 An earlier compilation cited in the same study gives 84.2% water, 8.9% protein, 4.1% sugar, 0.91% pectin and 0.7% ash.5 Cenicafé, the Colombian coffee research centre, gives 15% solids, in the form of a water-insoluble colloidal gel without cellular structure; 80% of these solids are pectic acids and 20% sugars.7 A 2022 Cuban review gives a slightly higher water content and similar sugar and pectin values: \"El principal componente del mucílago de café es la humedad (91,77%), seguido de los azúcares totales (6,43%), las pectinas (0,81%) y el nitrógeno (0,12%)\" – the main component of coffee mucilage is moisture (91.77%), followed by total sugars (6.43%), pectins (0.81%) and nitrogen (0.12%).8 The sources disagree most on pectin (see Contested). See [Mucilage](/entries/mucilage/) for its structure and the other published figures.\n\n## The seed is alive\n\nThe coffee seed is a living organism during processing. A 2007 study on Arabica tracked germination markers in seeds during processing and found that germination processes start, peak and fade during post-harvest treatment – with different timing and intensity for wet and dry processing.6 This is one reason why processing changes the chemistry of the seed itself, not only its surface. See [Washed process](/entries/washed-process/) and [Natural process](/entries/natural-process/) for the details.\n\n## Key studies\n\n
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Eckhardt et al., 2022 – Coffee cherry (cascara) products as food. A narrative review and risk assessment of foods made from the coffee fruit. It describes the structure of the cherry and how the wet, dry and semi-dry methods treat each layer, then assesses caffeine, EGCG and trigonelline exposure from cascara juice, jam, purée and flour.

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Molecules 27(23), 8435 · doi:10.3390/molecules27238435

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Bobková et al., 2022 – From cascara to silverskin. Compares fat, fatty acids and fibre in cascara, green and roasted beans and silverskin from dry-processed Panamanian Arabica, as a basis for using the by-products in food.

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Foods 11(8), 1082 · doi:10.3390/foods11081082

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Bytof et al., 2007 – Germination during post-harvest treatment. Shows that seed germination processes are switched on during processing and that their timing differs between wet and dry processing.

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Annals of Botany 100(1), 61–66 · doi:10.1093/aob/mcm068

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" }