Good agricultural practices define the identity and quality of coffee beans

Unlike other agricultural crops, coffee production has a very specific peculiarity, which is the high influence of the post-harvest stage on the quality of the product. Therefore, post-harvest management care must be associated with the adoption of good practices throughout the coffee growing cycle. In this context, the typification of identity and quality that defines the classification of processed coffee, raw beans, identifies defects, whose quantification is an indicator of product quality, which can be considered intrinsic or extrinsic.

Os intrinsic defects are black, green, burnt, cracked, badly grained, broken and broken grains, of genetic, physiological cause, or resulting from failures in agricultural processes (nutrition, pests, diseases, droughts, frosts, harvesting and preparation), or even that may occur after the fruits are removed from the field during the peeling, drying, storage and processing process. And the extrinsic defects refer to the presence of objects outside the standard of processed coffee (coconut, sailor, shell, sticks and stones).

Therefore, the search for coffee quality must involve good agricultural practices to reduce such defects throughout the cultivation phase. In this sense, the main causes of these defects and prevention measures are presented in the publications  Coffee defects e COFFEE MANUAL - Harvesting and Preparation, from the Technological Series of the Technical Assistance and Rural Extension Company of the State of Minas Gerais - Emater-MG, which are also available in full at the Café Observatory of the Café Research Consortium, coordinated by Embrapa Café.

Referenced publications from Emater-MG demonstrate that black, green and burnt beans (PVA) are the main defects in coffee and present good practices for preventing such defects. It also clarifies that, in farming, factors such as the advanced age of the coffee trees and very close spacing accentuate uneven flowering and increase the incidence of PVA beans. One measure to prevent these defects presented is that the harvest must begin with a minimum of green fruits, and end with a minimum of raisins and dried fruits. To achieve this, the property's processing capacity must be adequate to receive a greater quantity of freshly harvested fruits daily.

According to the Emater-MG Manual, the main cause of burnt and black grains is fermentation while still on the plant in very humid regions, rain during harvest or grains that are collected on the ground during harvest. Another point that promotes the fermentation of newly harvested fruits is that they remain in plastic bags for a long time while awaiting transportation to processing. This fermentation process occurs very quickly, since a cherry fruit is made up of approximately 85% water and 15% solids. One practice for reducing coffee defects is the elimination of poorly formed and broken fruits through the washing process that allows these fruits to be separated by density.

As for green beans, which come from the removal of fruits from plants before completing physiological maturation, causing them to remain green in color, the appearance of the coffee is altered and the roasting will have a lighter color, clashing with the predominant color. . This will also interfere with the drink, which will have an astringent flavor. Therefore, unripe fruits should be avoided from being harvested so that picking is not necessary and there is no depreciation of the drink.

Regarding broken grains, the occurrence may be related to the late completion of the harvest, because when the harvest is carried out late, for some reason, the grains that already have less moisture (raisins and dry) are still on the plant and are harvested together Those with higher humidity must go through the separation washing process. At the end of drying there will be two types of grains, one with the desired humidity and the other with humidity well below the desired level. If this separation has not been carried out, the grains that are drier than the rest of the batch will break during the peeling process, since the equipment settings will be adjusted for the rest of the batch.

In addition, as the documents cited further indicate, defects in flat and poorly formed grains may be related to nutritional deficiency, either due to lack of availability of nutrients, especially potassium, or due to lack of absorption conditions due to water issues or even due to the deficient root system. Another factor that must be considered is the lack of adaptation of the cultivar to the soil and climate conditions (soil and climate) to which the plant is subjected.

Finally, it is worth highlighting that another defect that occurs in raw coffee beans is due to attack by the coffee borer (hypothenemus hampei). This borer is also normally lodged from one harvest to another in grains that were not removed from the plant or in those that were left on the ground at the end of the harvest. To control the borer, it is necessary to harvest all the coffee fruits to prevent the coffee borer from remaining in the crop and, if applicable, apply appropriate chemical pesticides before it penetrates the grain and is protected, reducing the risk of efficiency of phytosanitary control. The drill feeds on the solids inside the grains, causing the grain to lose weight, among other problems that depreciate the product.

The influence of the defects mentioned on the physical classification of coffee is defined by the Ministry of Agriculture, Livestock and Supply – Mapa, through Normative Instruction No. 8, of June 11, 2003, which approved the Technical Regulation of Identity and Quality for the Classification of Raw Processed Coffee. This IN aims to define the identity and quality characteristics for the classification of processed raw coffee beans.