The Effects of Rainfall Patterns on Coffee Quality and Yield

Coffee and rainfall patterns are directly intertwined. While there are many factors affecting coffee production—soil, sunlight, altitude, wind, wildlife, farming practices, and more—rain is arguably the most critical element that can make or break a coffee crop.

Coffee farmers are constantly evaluating and adjusting their approach based on rain. Too much or too little can drastically impact both the crop’s yield and the beans’ cup quality and density. For instance, it is influenced by how much water the plant receives, which can impact how beans roast and develop flavor during brewing.

While navigating rainfall has always been a challenge, the effects of modern climate change are causing terroirs that were once havens for coffee plants to become unsuitable for growing. In some cases, the changes are so drastic that farmers are forced to grow new varieties or even leave their ancestral lands.

Understanding the link between coffee and rainfall helps us to appreciate the incredible amount of work that goes into every cup. Let’s explore the impact that shifting weather conditions have on the coffee industry, as well as solutions that are being implemented to keep everyone’s favorite bean sustainable.

The Effects of Excess Rain

Rain is crucial for growing coffee plants, but too much of a good thing can present significant challenges and have severe consequences. Excessive moisture can lead to a number of problems with both the crop’s yield and the quality of the harvested beans. Here’s a look at how too much coffee rainfall can damage plants. 

Dormant Flower Buds

When coffee plants begin the flowering process during a period of excessive rain, the flower buds may refuse to open, instead remaining dormant. This is one of the major factors affecting coffee production because the buds can end up falling off the plant before ever opening. And, if the buds do remain on the plant, the delayed flowering can cause deformations. In regions with real-time rainfall and weather tracking tech, some farmers monitor weather patterns closely to protect delicate flowering stages.

Soil Erosion

Excessive rainfall can erode the rich topsoil that delivers essential nutrients to the plants. This can occur slowly over time during periods of regular rainfall or rapidly during severe storms. Farmers in regions like Colombia and Kenya are combating this by using terracing and cover cropping specific to coffee, which helps stabilize soils to prevent nutrient loss and maintain long-term productivity.

Pest and Disease Control

When it comes to coffee, rainfall can wash away pesticides, fungicides, and various sprays used to control pests and diseases. Furthermore, high moisture levels can create ideal environments for pests and diseases to thrive.

Physical Damage

Harsh rain, wind, and other stormy elements can cause physical damage to the plants to the extent that they might not be able to recover. One easy solution to this is forest canopies, which can serve as natural umbrellas, shielding plants from heavy rainfall and mitigating storm damage.

Root Rot and Oxygen Deficiency

When the soil is constantly wet, the plants’ roots can rot. And, because the roots aren’t able to access oxygen, the planet can develop an oxygen deficiency. The increased wetness also fuels increased microbial activity that can lead to unintentional fermentation, resulting in “funky” flavors that must be managed carefully.

Fallen and Fermented Cherries

If heavy rains knock coffee cherries off the branches, they may ferment on the ground, leading to lower quality or even unusable beans for most specialty coffee producers.

Logistical Obstacles

When tending to coffee, rainfall can be an obstacle that prevents farmers from being able to work on a proper schedule. For example, heavy rainfall could make it impossible to climb mountain trails or even drive on rural roads.

Common Agricultural Solutions to Excess Rain

As you might assume, overcoming these factors affecting coffee production can be extremely challenging. But, here are some of the methods coffee farmers use to protect their crops.

• Planting coffee plants under nature’s umbrella—canopies of forest trees.

• Planting companion plants with extensive root systems helps to keep soil anchored in place.

• Planting companion plants that break down organic matter and release nutrients into the soil.

• Planting companion plants that attract beneficial microorganisms and insects that keep pests in check.

• Growing hardy coffee varieties that can withstand harsh conditions, such as Liberica and Excelsa.

The Effects of Drought

With coffee, rainfall in excessive amounts can be as much of a problem as not getting any rain at all. In fact, it can be worse, as it’s much more difficult to remove water than to add it. That said, drought can be a major problem, especially for farms that don’t have irrigation systems and unlimited water access. Here’s a look at how drought can affect the yield and quality of coffee plants.

Defoliation and Branch Death

Drought can cause branches to die and leaves to fall off. Leaves are essential to photosynthesis—the process of converting sunlight into energy. This is when plants struggle to generate energy, slowing growth and development, possibly leading to no blooming or drastic reduction in harvest.

Bean Damage

The coffee-rainfall connection directly impacts the quality of the beans the plants produce. Too little water can cause the beans to be too small or damaged when it’s time for harvest. Farmers in drought-prone areas use soil amendments like biochar to increase moisture retention, which has been shown to help mitigate these effects by holding water longer in the soil.

Low Yields

Extended drought periods can completely halt coffee production, resulting in drastically lower yields. In high-drought regions, farms have begun using partial root-zone drying, a technique where only half the root zone is watered, training plants to conserve resources.

Flower Shedding

Coffee plants may begin to shed flowers if they don’t get enough water. This can take place within days. Fewer cherries means less harvest, a direct hit to the farmer’s income.

Underdeveloped Buds

When it comes to coffee, rainfall timing and consistency matters, too. If a drought occurs after buds have already emerged, they may not fully develop, also leading to uneven ripening. 

Heat Damage

Periods of drought often come with periods of excessive heat. High temperatures can cause a number of stress-related problems, including yellowing and wilting leaves, stunted growth, premature flowering, and an inability to ward off diseases and pests. Heat-tolerant varieties like Stenophylla are being trialed for their drought resilience, potentially offering a solution for high-heat regions.

Common Agricultural Solutions to Drought

• Planting a layer of beneficial weeds and other plants helps the soil retain moisture by slowing evaporation.

• Removing harmful weeds that use the limited moisture available.

• Spreading leaves, branches, mulch, and other biomass on the ground so they decompose, moisturize, and enrich the soil.

• Implementing emergency irrigation systems.

• Recycling and storing water in reservoirs.

• Planting hardy coffee species that can survive drought.

Support Independent Coffee Farms

Coffee rainfall is unpredictable, especially with climate change disrupting the usual patterns that many farmers have depended on for generations. These environmental factors affecting coffee production can be devastating for family-owned farms and local communities. But we believe that you can make a difference.

At Ebru Coffee, we proudly partner with farms around the globe to bring you specialty coffee beans grown, harvested, processed, and roasted with love. Our single-origin coffees are always sustainable, single-farm, single-season, single-harvest batches that meet our stringent quality standards. 

We believe that coffee culture can positively impact both people and the planet. While we can’t change the weather, we can support farmers adapting to climate challenges. By choosing farm-to-cup coffee, you’re not only supporting sustainable practices, but you’re also enjoying flavors you won’t find with the big names. Discover your new favorite coffee, and join us in making a difference.