Essential Good Practices for Producing High-Quality Coffee

Quality coffee is not the result of a single good decision – it is the outcome of dozens of careful, consistent choices made from the moment a cherry is ready to be picked to the moment it leaves the farm gate. Research published on IntechOpen confirms that post-harvest processing activities alone account for roughly 60% of the final quality of green coffee beans. This means that even the most carefully cultivated crop can be undermined by poor harvesting, careless handling, or inadequate storage. Good Agricultural Practices (GAP) and Good Manufacturing Practices (GMP) exist precisely to prevent that from happening – they form a structured, stage-by-stage framework that protects coffee’s intrinsic quality all the way to the market.

Why GAP and GMP matter in coffee production 🔗

Sustainable specialty coffee production research makes clear that obtaining quality coffee requires cultivation techniques that are in accordance with GAP, environmentally friendly, and adaptive to changing conditions. GAP covers what happens in the field – how and when cherries are harvested, how the farm is managed, how inputs are used. GMP picks up once the cherries enter the processing stage, covering equipment hygiene, water quality, drying protocols, and storage conditions. Together, they create an unbroken chain of quality control. Critically, mistakes made early in this chain cannot be corrected later. A defective cherry processed alongside ripe ones will affect the flavor of an entire batch. A poorly cleaned pulper can introduce microbial contamination that no amount of drying can fix. This is why prevention – not correction – is at the heart of both GAP and GMP.

Harvesting: the first and most important quality decision 🔗

Everything begins with the harvest. The ripeness of a coffee cherry at the moment of picking has a direct and irreversible impact on flavor, body, and the risk of contamination. Both underripe and overripe cherries are problematic. Scientific literature on specialty coffee production notes that overripe cherries have poor physical and beverage quality, and that Ochratoxin A (OTA) contamination levels are higher in coffee derived from both immature and overripe fruit.

Selective picking as a GAP standard 🔗

Coffee estate management guidelines identify selective picking – harvesting only ripe, red cherries – as a core best practice to ensure flavor uniformity and reduce defects. Because not all cherries on a single tree ripen at the same time, this often means making multiple passes through the same plot over several days or weeks. While more labor-intensive, this approach is the cornerstone of quality production at the estate level. Workers should be trained to distinguish ripeness by color and firmness, and collection containers should be made from food-grade materials that prevent chemical contamination and allow adequate air circulation.

Sorting after harvest 🔗

Even with selective picking, sorting remains essential. Post-harvest processing guidance from Perfect Daily Grind explains that after harvest, cherries are washed and sorted using a float test – underdeveloped or overripe cherries float in water, while properly ripe cherries sink. This simple step, performed manually or with dedicated equipment, removes a significant portion of defective material before processing begins. According to GMP compliance research published on ResearchGate, sorting out defective seeds – particularly black, fungus-affected, or broken beans – can substantially reduce ochratoxin contamination in the final product.

Processing: choosing the right method and maintaining hygiene 🔗

Once sorted, cherries must be processed promptly. Research published in the journal Molecules (MDPI) confirms that fruits should be processed immediately after harvesting to limit the occurrence of unwanted fermentation and reduce contamination. The method chosen – dry (natural), wet (washed), or honey – each carries its own quality and hygiene requirements, but all share the same non-negotiable baseline: clean equipment, clean water, and controlled conditions.

Wet processing and water quality 🔗

Wet processing involves removing the cherry pulp before drying, followed by fermentation to remove the mucilage layer, and then washing. At every stage, water quality is critical. Processing water should have a neutral pH between 6.5 and 7.5, low mineral content, and be completely free of harmful microorganisms or chemical contaminants. Treatment may involve filtration, UV sterilization, or chlorination, but any method must ensure that residual chemicals do not interfere with fermentation or affect flavor. Fermentation itself, which typically takes 12 to 48 hours depending on temperature and altitude, must be carefully monitored – published research on post-harvest processing identifies Aspergillus, Penicillium, and Fusarium among the mold species most commonly associated with coffee processing, all of which can proliferate under poorly controlled fermentation conditions.

Equipment hygiene under GMP 🔗

All processing equipment – pulpers, fermentation tanks, washing channels – requires systematic cleaning that prevents microbial buildup between batches. A peer-reviewed review on OTA reduction strategies in coffee emphasizes that good hygiene practices, including regular disinfection, are paramount to avoid equipment contamination with mycotoxin-producing fungi. Daily cleaning should include full disassembly of removable parts, washing with appropriate detergents, and sanitization before reuse. Deep cleaning on a weekly or monthly basis should address internal piping, motor housings, and structural joints where organic matter tends to accumulate. Documenting cleaning activities helps maintain consistency and flags problem areas early.

Drying: the most critical processing stage 🔗

Drying is where the most quality gains – and losses – occur. The objective is to reduce the moisture content of the coffee from approximately 60% at harvest to a stable 10-12%, at which point microbial activity effectively ceases and the beans are safe for long-term storage. Guidelines from the European Coffee Federation on OTA risk management state that rapid drying to a moisture content between 8% and 12.5%, combined with clean and dry storage, is among the most important protective measures a producer can take.

Raised bed drying vs. ground drying 🔗

Industry guidance on post-harvest practices recommends drying coffee on raised beds rather than directly on the ground. Raised beds prevent contamination from soil contact and improve ventilation for more even drying across the entire batch. Where drying machines are used, static dryers that ventilate from below offer more controlled pre-drying, while rotary dryers require the coffee to be pre-dried before loading. Regardless of the method used, cherries or parchment must be turned regularly to ensure uniform drying and prevent hotspots where moisture can linger and mold can develop.

Understanding the drying phases and mold risk 🔗

The drying process passes through distinct phases that carry different mold risks. Research on OTA occurrence and management describes a critical transition phase at around 0.90 water activity – roughly equivalent to 13-16% moisture – during which xerophilic fungi and OTA-producing species like Aspergillus are most active. A study on storage fungi in Arabica coffee from Northern Thailand confirms that at moisture content around 13%, molds such as Rhizopus and Aspergillus can begin to develop actively. This means that slow drying, or leaving coffee exposed to rain or high humidity during the drying process, significantly elevates contamination risk. Producers must monitor moisture content continuously and halt drying only when safe levels are confirmed.

Preventing contamination: chemical and microbial risks 🔗

Quality loss through contamination can come from two main directions: microbial (primarily mold and the mycotoxins they produce) and chemical (pesticide residues, cleaning agents, or contact with non-food-grade materials). Both types of contamination can render coffee unsaleable and unsafe.

Managing OTA risk through good practices 🔗

Ochratoxin A (OTA) is the mycotoxin most closely associated with coffee. A food safety analysis published in the Journal of Food Science notes that the Codex Alimentarius Best Practices recommend keeping moisture in green coffee below 12.5% to reduce the likelihood of mold growth, and that removal of visually defective beans with earthy or moldy aromas reduces the frequency of detecting OTA at concerning levels. The European Commission has set maximum limits of 3 µg/kg for roasted coffee and 5 µg/kg for soluble coffee, making OTA management not just a quality issue but a legal compliance matter for export markets. Early and visible defects are the best indicator – European Coffee Federation guidelines note that an earthy or moldy smell should always trigger further investigation of a lot before processing continues.

Cross-contamination prevention 🔗

Chemical contamination is most commonly introduced through inadequate segregation of coffee processing areas from other farm activities, use of non-dedicated equipment, or the presence of residual cleaning chemicals. Good practice requires that coffee processing areas be physically separate from storage of pesticides, fuel, or other agricultural chemicals. Personnel should be trained specifically on contamination risks and on the proper use of equipment assigned exclusively to coffee processing. Insect-damaged beans represent a particular risk – once the protective skin of the cherry is breached by insects such as the coffee berry borer, the bean is directly exposed to fungal colonization, and such beans should be systematically removed during sorting.

Storage: protecting quality after processing 🔗

Proper storage is the final line of defense before coffee leaves the estate. Post-harvest handling recommendations are clear: beans must be stored in suitable, healthy containers and kept in a ventilated area with low humidity. Specialty coffee moisture management standards confirm that the Specialty Coffee Association (SCA) recommends drying green beans to 10-12% moisture content, which dramatically lowers the risk of mold growth during storage. In practice, this means storing beans away from direct sunlight and moisture, in clean warehouses with adequate air circulation. Parchment or green coffee should never be stored alongside produce with strong odors, chemicals, or materials that could transfer contamination.

Quality monitoring and documentation 🔗

GAP and GMP are not simply a list of procedures to follow – they require an ongoing system of monitoring, sampling, and documentation. Critical control points throughout the production chain need to be identified, with specific protocols for each. These typically include harvest quality assessments (ripeness checks), fermentation time and temperature records, drying moisture measurements at regular intervals, and storage condition logs. Random sampling at multiple process stages provides data for identifying trends and catching problems before they affect an entire batch. Industry experience from specialty coffee producers in Brazil shows that having a structured, documented approach – rather than relying on accumulated experience alone – directly improves cup scores and consistency season after season. Documentation also enables traceability, which is increasingly required by specialty buyers and international export markets.

What do you think? Given that post-harvest processing contributes around 60% of green coffee quality, which single practice – careful selective harvesting, strict drying protocols, or contamination prevention – do you consider the most critical for an estate-level producer to get right first? And as buyers increasingly demand full traceability from farm to cup, how realistic is it for smallholder coffee estates to implement and maintain comprehensive GAP and GMP documentation systems?

References

1. https://www.intechopen.com/chapters/70151
2. https://iopscience.iop.org/article/10.1088/1755-1315/1230/1/012067/pdf
3. https://farmonaut.com/blogs/coffee-estate-management-10-powerful-sustainable-practices
4. https://perfectdailygrind.com/2021/01/exploring-post-harvest-practices-their-relationship-with-coffee-quality/
5. https://www.researchgate.net/publication/341218194_Evaluation_of_post-harvest_coffee_to_conform_with_good_manufacturing_practices_GMP_to_develop_entrepreneurship
6. https://www.mdpi.com/1420-3049/28/21/7386
7. https://pmc.ncbi.nlm.nih.gov/articles/PMC10650074/
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC11355758/
9. https://www.ecf-coffee.org/wp-content/uploads/2022/02/Guidelines-for-the-prevention-of-OTA-occurence-in-Coffee_February2022_FINAL.pdf
10. https://www.sciencedirect.com/science/article/abs/pii/S0956713521004898
11. https://ift.onlinelibrary.wiley.com/doi/10.1111/1750-3841.15938
12. https://frequentcoffee.com/blogs/journal/mold-and-mycotoxins-in-coffee-safety-guide
13. https://perfectdailygrind.com/2026/02/how-to-encourage-producers-to-grow-specialty-coffee/