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Why We Dry Coffee in the Shade

Why We Dry Coffee in the Shade

At Copala, we dry our coffee slowly on raised trays, protected from harsh direct sunlight.

This happens after the ripe cherries have been hand-picked, float-sorted, depulped and fermented in water for 24–36 hours. Once drying is complete, the parchment is removed and the green coffee is gravity sorted, bagged, shipped to South Africa and sized by class before roasting.

Drying is one stage in a much longer process, but it has an important influence on the coffee that eventually reaches the roaster. We choose shade because it gives us a more controlled way to manage heat, airflow, moisture loss and drying time.

Drying Is a Quality Decision

Freshly processed parchment coffee contains too much water to be hulled, stored or transported safely. Drying gradually reduces that moisture until the coffee is stable enough for the stages that follow.

How the water is removed matters. Studies comparing coffee-drying methods have measured differences in chlorogenic acids, antioxidant activity, colour, fatty-acid composition and volatile compounds in the resulting green coffee.[1,2] These are not all flavour compounds in their own right, but they form part of the chemical material that drying preserves or changes and that roasting later transforms.

Sugars and amino acids contribute to Maillard reactions during roasting. Organic acids help shape the perception of brightness and balance, while chlorogenic acids and their breakdown products can contribute to acidity, bitterness and complexity. Drying therefore helps determine what the roaster has available to work with.

The research does not establish one drying method as universally best. Results depend on the coffee species, post-harvest process, equipment, temperature, humidity, airflow and final moisture. Copala’s choice is more specific: shade drying suits our washed coffee, our estate and the level of attention we want to give each lot.

What Shade Changes

Direct sunlight does more than illuminate coffee. It transfers radiant energy to the parchment and to the surface beneath it. Under strong sun, the outside of the coffee can warm quickly and lose water faster than moisture from deeper within the bean can move towards the surface.

Shade reduces that direct solar heat load. Our raised trays allow air to circulate around the parchment while protecting it from the strongest sunlight. This places greater emphasis on airflow and gradual evaporation rather than rapid surface heating.

Controlled research supports the importance of managing both temperature and drying rate. In one study of mechanically dried natural coffee, a faster drying rate at 35°C reduced sensory scores both shortly after drying and after storage. At 40°C, the negative association appeared after seven months of storage. At 45°C, thermal damage dominated: every treatment produced lower sensory scores than the coffees dried at 35°C or 40°C.[3]

That study used natural coffee in a controlled mechanical system rather than Copala’s washed parchment on raised trays, so its temperatures and results should not be transferred directly to our process. Its broader lesson is still relevant: removing water faster or with more heat does not automatically produce better coffee.

UV Is Energy — but Absorption Matters

Ultraviolet radiation carries enough energy to initiate photochemical reactions in molecules that absorb it. Absorption is the essential qualification: not every organic molecule absorbs every UV wavelength, and absorbed UV does not always break a bond. Depending on the molecule and its surroundings, photochemistry can lead to oxidation, isomerisation, molecular rearrangement or bond cleavage.[4]

It is therefore accurate to say that UV has the capacity to alter susceptible organic molecules. It is not accurate to say that every UV exposure necessarily changes every molecule it reaches. Wavelength, dose, oxygen, moisture, temperature and the composition of the material all influence what happens.

Research on other harvested plants illustrates the principle. In a study comparing sun, shade and oven drying, shade-dried peppermint produced a higher essential-oil yield and a higher proportion of iso-menthone than sun-dried peppermint, although other compounds responded differently to the three methods.[5] The result is a reminder that drying conditions can change the balance of volatile plant compounds rather than affecting every compound in the same way.

A laboratory study of anthocyanin-rich grumixama berry extracts found much faster pigment degradation under a 25 W ultraviolet lamp than under the fluorescent or incandescent lamps used in the experiment.[6] That was a berry extract under artificial light, not parchment coffee in sunlight, and the light sources were not equivalent in spectrum or intensity. It demonstrates UV-driven degradation in a susceptible plant compound; it does not prove that sunlight destroys a particular coffee flavour molecule during drying.

For Copala, limiting unnecessary direct UV exposure is a prudent additional safeguard. Shade does not eliminate UV, but it reduces direct solar exposure while also helping us moderate heat and drying rate. We choose the gentler, more controllable environment because our aim is to carry the character of the harvest forward, not to let one forceful processing variable dominate it.

Why We Dry Slowly

Water does not leave a coffee bean all at once. Moisture near the surface is removed first. Water from deeper within the bean must then migrate outwards before it can evaporate. When the surface dries much faster than the centre, a larger moisture difference develops across the bean. A moderate drying rate gives that internal moisture more time to move out progressively.

Slow drying does not mean extending the process for its own sake. It means avoiding unnecessarily rapid moisture loss and the temperature peaks that can occur under intense direct sun.

Nor does slow mean unattended. Coffee that remains within moisture conditions favourable to fungal growth for too long faces a different risk. Research and international guidance both emphasise control of water activity, regular turning, airflow and protection from rewetting.[7,8]

At Copala, the coffee is spread appropriately, turned regularly and protected from rain, condensation and rewetting. The objective is not the longest possible drying time. It is a steady progression between two undesirable extremes: coffee driven dry by excessive heat and coffee left damp for too long.

Carrying the Coffee’s Character Forward

The character of a coffee begins on the farm. Variety, soil, altitude, weather, cherry ripeness and fermentation all influence the bean. Drying then carries that character into a stable green coffee that can be hulled, sorted, transported and roasted.

Roasting continues that progression. The compounds present in green coffee react and transform to create much of the sweetness, body and aroma experienced in the cup. The roaster is not simply adding flavour to a neutral bean; roasting develops material shaped by the farm and by every processing stage that preceded it.

This is why Copala’s shade drying and medium roasting follow the same principle. We shade-dry to guide the harvest carefully into stable green coffee. We then roast to medium to develop sweetness, body and aromas associated with cocoa, toasted nuts and caramel, without allowing heavy roast flavours to overwhelm the coffee itself.

Why Shade Suits Copala

Shade drying suits the scale and methods of our family estate. It allows us to spread the coffee on raised trays, expose it to natural airflow and protect it from the strongest direct sunlight. The process remains gradual, visible and manageable.

It is an attentive method. It requires time, space and regular observation. Shade alone is not a guarantee of quality; the result depends on airflow, layer depth, turning, weather protection and knowing when the coffee has reached a stable moisture level. Those are the details the method allows us to watch closely.

Once the coffee is dry, our work continues. The parchment is removed, and the green coffee is gravity sorted to separate lighter, defective beans from denser coffee. It is then bagged, shipped to South Africa and sized by class before roasting.

We dry in the shade because it gives us greater control over one of the stages that shapes the coffee reaching the roaster.

From the tree to the drying tray, and from the green bean to the roast, our approach remains the same: develop the coffee carefully without allowing one part of the process to overpower everything that came before it.

References

  1. Kulapichitr, F., Borompichaichartkul, C., Fang, M., Suppavorasatit, I. and Cadwallader, K. R. “Effect of Post-Harvest Drying Process on Chlorogenic Acids, Antioxidant Activities and CIE-Lab Color of Thai Arabica Green Coffee Beans.” Food Chemistry 366, 130504 (2022). https://doi.org/10.1016/j.foodchem.2021.130504

  2. Dong, W., Hu, R., Chu, Z., Zhao, J. and Tan, L. “Effect of Different Drying Techniques on Bioactive Components, Fatty Acid Composition, and Volatile Profile of Robusta Coffee Beans.” Food Chemistry 234, 121–130 (2017). https://doi.org/10.1016/j.foodchem.2017.04.156

  3. Borém, F. M., Isquierdo, E. P., Alves, G. E., Ribeiro, D. E., Siqueira, V. C. and Taveira, J. H. S. “Quality of Natural Coffee Dried under Different Temperatures and Drying Rates.” Coffee Science 13, 159–167 (2018). https://doi.org/10.25186/cs.v13i2.1410

  4. Braslavsky, S. E. “Glossary of Terms Used in Photochemistry, 3rd Edition (IUPAC Recommendations 2006).” Pure and Applied Chemistry 79, 293–465 (2007). https://doi.org/10.1351/pac200779030293

  5. Xylia, P., Chrysargyris, A., Tomou, E.-M., Goumenos, C., Skaltsa, H. and Tzortzakis, N. “Quality Characteristics and Essential Oil Properties of Thymus capitatus, Mentha piperita, and Sideritis cypria Dried under Different Conditions.” Plants 13, 3150 (2024). https://doi.org/10.3390/plants13223150

  6. Modesto Junior, E. N., Martins, M. G., Pereira, G. A., Chisté, R. C. and Pena, R. S. “Stability Kinetics of Anthocyanins of Grumixama Berries During Thermal and Light Treatments.” Foods 12, 565 (2023). https://doi.org/10.3390/foods12030565

  7. Abreu, D. J. M. et al. “Influence of Drying Methods on the Post-Harvest Quality of Coffee: Effects on Physicochemical, Sensory, and Microbiological Composition.” Foods 14, 1463 (2025). https://doi.org/10.3390/foods14091463

  8. Codex Alimentarius Commission. Code of Practice for the Prevention and Reduction of Ochratoxin A Contamination in Coffee, CXC 69-2009 (2009). https://workspace.fao.org/sites/codex/Standards/CXC%2069-2009/CXC_069e.pdf