EN 
PT_BR 
Post-harvest of bean It encompasses a series of operations that begin at the harvest point and end with delivery to the buyer. Harvesting, threshing, drying, cleaning, sorting, storage, and transportation are steps that can cause weight loss, mechanical damage, and a decrease in the commercial quality of the grains. Therefore, proper management throughout the entire process is fundamental to preserving the value of the production.
Beans are cultivated at different times and using different systems in virtually all regions of Brazil. Despite this, on many farms, attention is focused on the period between planting and harvesting, while subsequent operations receive less care. This scenario can lead to production losses caused by broken or damaged beans, impurities, insects, and fungi during storage.
Besides reduced volume, post-harvest problems also affect quality. Grains with uneven color, blemishes, mechanical damage, or high moisture content can be devalued by buyers and, in some cases, lead to the lots being rejected. Because beans are sensitive to moisture and temperature, inadequate care between harvesting and marketing can compromise the results obtained during cultivation.
Post-harvest processing begins with determining the appropriate point for harvesting from the field. This decision considers the maturity of the plants and pods, as well as the moisture content of the grains.
Next comes the harvest, which can be manual or mechanized. Depending on the system, the plants may be cut and then threshed or pass directly through a harvester. Threshing separates the grains from the pods and other plant structures. Afterwards, drying reduces the moisture to levels suitable for storage.
The product then undergoes cleaning and sorting, which removes impurities, substandard grains, and unwanted materials. The batch can then be stored until the time of sale. The final stage is transportation to grain dealers, cooperatives, industries, or other buyers. Physical and quality losses can occur in all these operations.
An inappropriate choice of harvest time is among the primary factors that can cause losses. Harvesting too early can result in grains that are still green and have high moisture content, while delaying increases the risk of pod dehiscence and grain falling to the ground.
In mechanized harvesting, improper adjustments also increase damage. Very high rotation speeds, incorrect concave opening, excessive speed, and misadjusted sieves can increase breakage and grain loss in the straw.
Drying requires similar attention. When it is slow, the grains remain with high moisture content for longer, favoring mold growth and overheating. On the other hand, excessive temperatures or very rapid drying can cause cracks, internal fissures, and increased breakage.
Poorly designed structures also compromise the process. Very thick layers, insufficient turning, and poor ventilation hinder uniform drying.
In storage, leaks, damp floors, high temperatures, and lack of ventilation promote deterioration. Sacks in direct contact with the floor and stacked without aisles also increase the risks. During transport, dirty or damp vehicles, exposure to rain and sun, improper handling, and grain spillage can compromise the batch.
Since small losses at each stage accumulate, monitoring and recording losses during operations helps identify key areas for correction.
Most of the pods should be dry or at physiological maturity, with few green pods remaining. The leaves are usually already dry or fallen. The grain moisture also needs to be monitored. In mechanized harvesting, the product cannot be excessively wet or too dry, as both situations can increase damage. The measurement should be carried out with properly calibrated equipment.
The climate is another deciding factor. During periods of high humidity or frequent rainfall during ripening, delaying harvesting can increase the risk of pod sprouting, rotting, spotting, and dehiscence. In some situations, it may be preferable to harvest when the fruit is still moist and then conduct more careful drying afterward.
The harvesting system also affects the operational window. In manual harvesting with drying of the branches, the cut can be brought forward, allowing the plants to complete drying outside the field. In fully mechanized harvesting, the window tends to be narrower and requires frequent monitoring of maturation.
In manual or semi-mechanized harvesting, planning the cutting process is important. When possible, the operation should be carried out during the coolest hours of the day to reduce grain loss caused by the dehiscence of very dry pods. After cutting, the stalks should be taken to a suitable place for drying and threshing, avoiding prolonged contact with damp soil and exposure to rain.
Plant piles need to remain well-ventilated. Green and dry material should not be excessively piled up, as this hinders drying and promotes fungal growth. In mechanized harvesting, the threshing system should be adjusted to allow for grain separation without excessive force.
High cylinder rotation and very small clearance can increase breakage and mechanical damage. The travel speed also needs to be adequate to maintain threshing and separation efficiency. Sieves and fans should be adjusted to remove impurities without expelling good grains from the machine. Periodic evaluation of losses in the harvester's trail and within the grain tank allows for adjustments during operation.
Drying is one of the main post-harvest steps, as it determines part of the product's stability during storage. The goal is to achieve a safe moisture level without causing physical damage or loss of quality.
In natural drying, the producer should use clean, impermeable surfaces, such as drying yards, concrete floors, or plastic tarps. The formation of thin layers facilitates uniform drying. Very thick layers increase the risk of overheating and mold formation.
Frequent turning also helps to homogenize drying and reduce the time in conditions favorable to fungal growth. The grains must be protected from rain and dew. The operation needs to be organized so that the product is spread after the dew has dried and collected or covered before nightfall or rain occurs.
Where artificial dryers are used, the process allows for greater control of the final moisture content. The air temperature must be adjusted to the sensitivity of the beans, avoiding excessive heating.
It is also necessary to control the drying time in the dryer and monitor the moisture content with representative samples and calibrated meters. The goal is to start drying as quickly as possible after threshing, preventing the grains from remaining with high moisture content for several days.
After drying, the beans must be cleaned and sorted according to market requirements. Cleaning removes husks, stones, clods, pod fragments, and shriveled, very small, or damaged beans. Sorting by size allows the beans to be separated into different fractions, which may have distinct commercial uses.
Separation by color and type can also be carried out, removing stained, darkened, or otherwise discolored grains. In more technologically advanced facilities, optical sorting systems can be used. On a smaller scale, manual sorting can also contribute to improving the appearance of the batch.
Each buyer's standards must be known before the sale. Grain traders, cooperatives, and industries may establish different criteria and discounts for moisture, impurities, broken, damaged, and stained grains.
After drying and cleaning, beans can be stored until sale. During this period, humidity, temperature, and storage time determine some of the risks of loss. The moisture content of the beans should be measured with appropriate equipment and maintained within a safe range for the intended storage period.
Warm environments accelerate grain metabolism and promote the growth of insects and fungi. Therefore, ventilation and measures to reduce warehouse heating are important. Relative air humidity also needs to be considered. Infiltration, inadequate flooring, and lack of ventilation control can promote rewetting of surface layers.
When the product is stored in sacks, the sacks should not be placed directly on the floor. The use of pallets helps to prevent contact with moisture. Stacks should be of a height compatible with the strength of the sacks and allow for aisles for air circulation and inspection. The environment must remain clean, with the removal of grain remnants, dust, and other residues that could harbor insects and rodents.
Weevils and other stored grain pests can cause weight and quality losses. Prevention begins with cleaning the warehouse before a new harvest arrives. Periodic inspections allow for the identification of insects, grain dust, moldy odors, and color changes.
When chemical control is necessary, application must be carried out with registered products and in accordance with the label, instructions, legislation, and guidance of a qualified professional.
Care doesn't end in the warehouse. During transport, trucks and trailers must be clean and dry, free of residue from previous loads. Cargo needs to be protected from rain and excessive sun exposure. Intact tarpaulins help prevent wetting and overheating. Sacks should be handled carefully to avoid falls, throws, and dragging that could break the packaging and cause grain spoilage.
Before shipment, it is also important to check the weight, documents, and, when possible, moisture and impurity levels. These checks help reduce surprises upon receipt of the product by the buyer and allow for the identification of problems before delivery.
Reducing post-harvest losses also depends on decisions made during crop planning. Choosing cultivars with characteristics suitable for harvesting, such as greater resistance to breakage and less susceptibility to dehiscence, can help reduce risks. Staggering planting also helps distribute the harvest and avoid periods when dryers, drying yards, and warehouses are overloaded.
Before planting, it is necessary to assess whether the drying and storage infrastructure is sufficient for the expected production volume. Team training completes the planning. Machine operators and workers need to know the procedures that affect grain preservation.
Post-harvest operations must follow occupational safety and plant health regulations. Operators of harvesters, threshers, dryers, and warehouse workers must use the appropriate Personal Protective Equipment (PPE) for each activity.
The use of chemical products for pest control in stored grains should only occur with registered products and by strictly following the label and instructions.
Preventive maintenance of equipment is also part of proper management. Poorly maintained machines can increase both the risk of accidents and grain losses.
Maintaining records of harvest dates, batches, moisture content, drying procedures, and delivery quality allows for the identification of areas for improvement and contributes to production traceability. Ultimately, reducing losses depends on the integration of all stages. A good harvest point, correctly adjusted machinery, controlled drying, efficient cleaning, proper storage, and careful transportation help preserve quantity and quality until the product is sold.
