What are defective beans? how to calculate defective beans?

High-quality coffee beans are refined by water treatment. The coffee beans with less impurities can be obtained by the water washing method, but if the water quality and time are not properly controlled during the fermentation process, the coffee beans will easily be infected with the sour taste of excessive fermentation. and dry beans also need to pay attention to timely re-inspection to prevent coffee beans from being contaminated by wet ground and sundries. Processed beans should be dried in time, and the drying should also have a certain degree. Generally, the moisture content of processed beans is 11% 13%. Insufficient drying can easily make beans moldy, and excessive drying can easily affect the flavor of beans.

Defective name: all black beans

SCAA level:

The all-black bean is a first-class defect.

1 obvious all-black bean = 1 complete defect

Name of defect: partial black bean

SCAA level:

Partial black bean is a secondary defect.

Less than half of 1 bean is black, 3 beans = 1 complete defect

Causes:

1) Agriculture: blackening is the result of excessive fermentation of pigments by microorganisms.

Precautionary measures:

1) Agriculture. Black beans can be prevented during picking, picking ripe fruits only from trees, and avoiding excessive fermentation during farm processing.

2) deal with. When the endocarp of the coffee bean is removed, the black bean is very obvious. They are usually small and low-density, and some can be removed through sieves and density classifiers. The most effective way to select black beans is through hand selection or color classifier.

Defective name: whole sour bean

SCAA level:

The whole sour bean is a first-class defect.

A whole sour bean = a complete flaw

Name of defect: local sour bean

SCAA level:

Local sour bean is a secondary defect.

Less than half of a bean is sour beans, 3 beans = 1 complete defect

Causes:

Agriculture and treatment. Sour beans are caused by fermentation, which is the result of contamination by microbacteria in many places in the process of harvest and treatment. Specific reasons include: picking overripe fruit, harvesting fallen fruit, water pollution during treatment, or excessive fermentation due to wet environment when the fruit is still attached to the tree.

Precautionary measures:

1) Agriculture: only pick ripe fruits (avoid overripe fruits), do not harvest fallen fruits, and do not grow coffee in low-altitude areas near rivers, lakes or dams to avoid over-fermenting coffee beans.

2) treatment: sour beans can be avoided by ensuring timely removal of pulp (immediately after picking to avoid delaying storage). When the whole water is washed, the fermentation time in the fermentation tank is controlled. Avoid pollution or recycling water in the process of washing out. Drying treatment should be completed in time and continuously. When coffee beans remove endocarp, sour beans are obvious, color classifiers and hand-selected classifiers can remove many parts of sour beans.

Defect name: mildew bean

SCAA level:

First-class flaw.

1 moldy bean = 1 complete defect

Causes:

Agriculture and treatment. Moldy beans are usually infected by Aspergillus and Penicillium fungi. Inappropriate temperature and humidity can cause Fusarium infection to coffee beans everywhere from picking to storage. It will induce mold growth. If mold spores appear, fungi will only grow under these conditions.

Precautionary measures:

1) Agriculture: coffee must be planted in producing areas with suitable temperature and humidity, this environment is also suitable for mold growth, and efforts must be made to inhibit the production of bacteria from mold sources. This includes harvesting fruits from the ground or severely moth-eaten, as well as coffee beans left in harvesting baskets and drying tanks.

2) treatment: good fresh fruit processing and shelling processing can prevent coffee infection. The causes of infection include coffee beans that break or break when the pulp is removed, leaving beans in the fermentation tank, delaying drying, interrupting the drying process, worming, and storing shelled beans in high humidity and high temperature.

3) Agronomy: only pick ripe fruits (avoid overripe fruits), do not harvest fallen fruits, and do not grow coffee in low-altitude areas near rivers, lakes or dams to avoid over-fermenting coffee beans. Moldy beans are obvious when coffee beans are shelled and endocarp removed. At this stage, the color classifier removes many parts of heavily moldy infected coffee beans, while slightly moldy beans can only be removed by hand.

Name of defect: foreign body

SCAA level:

First-class flaw.

1 foreign body = 1 complete defect

Causes:

Variety: foreign bodies can be produced in any process.

Precautionary measures:

1) Agriculture: none.

2) treatment: foreign bodies can be removed or avoided in the following ways:

Pay attention to branches and leaves when picking.

Pay attention to other substances, such as stones, sawdust, nails, etc., when drying in the sun.

In the shelling plant, use appropriate equipment, such as stone removers, magnets, to effectively remove foreign bodies.

Defective name: coffee dried fruit / dried pod

SCAA level:

First-class flaw.

1 dried fruit

Or dried pod = 1 complete defect

Causes:

1) Agriculture: drought and disease make the fruit dry on the trees and even fall to the ground.

2) treatment: in washed coffee, the presence of dried coffee fruits or dried pods is the result of a low-end pulp removal process and the failure of primary selection of floating beans (dried fruits) with water at the receiving station, and the equipment is not maintained or adjusted. In sun-treated coffee, the presence of dried fruits or pods is the result of inappropriate shelling and grading.

Precautionary measures:

1) Agriculture: avoid harvesting dried fruit from the ground or trees.

2) treatment: when there are too many dried fruits, the sheller can not be removed effectively. Removing all floating beans at the receiving station and maintaining the correct proofreading and maintenance of the pulp removal machine will reduce the production of dried fruit. Any dried pods that pass through the sheller can be selected and removed by a degree classifier during shelling processing.

Defective name: moth-eaten bean

SCAA level:

Serious borer bean is a first-class defect, 3 or more perforations

5 serious worm-eaten beans = 1 complete defect

SCAA level:

The pea is a secondary defect, with less than 3 perforations.

10 slight worm-eaten beans = 1 complete defect

Causes:

1) Agriculture: the berry bug is the most serious pest in coffee cultivation. The insect (coffee fruit bark beetle) pecks holes in coffee fruits and trees, digs channels in soft seeds and lays eggs. Newborn eggs usually appear from the other end, creating two holes in a coffee bean. It is not common to have multiple channels in a bean. The incidence of this disease often increases and decreases with altitude.

Precautionary measures:

1) Agriculture: the best way to avoid moth-eaten coffee is to observe and put an end to the breeding conditions of insect pests. Spraying is an option, but its impact is limited, requiring integrated pest management techniques (e.g. special design for fungal management) (Beauveria bassiana) and the use of African wasps, as pests multiply in seeds, it is necessary to pick up all coffee fruits that fall on the ground to eliminate the conditions for their reproduction and spread. In addition, the pulp of mature fruit can carry diseases and insects, so there should be a reasonable distance between the tree and complete composting. It is not feasible to identify healthy and moth-eaten fruits during picking, because the damage is generally internal and cannot be detected without very careful observation.

2) treatment: after being transported to the shelling processing plant, the moth-eaten coffee beans become obvious after the endocarp is removed. At this stage, the density classifier can remove many parts of the seriously moth-eaten beans. If the coffee is seriously infected, it should be selected by hand. Serious pest infection has a devastating effect on farmers, making it impossible to export most of the harvest.

Damage during wet grinding

Damage during dry grinding

Defect name: broken bean, broken bean, broken bean

SCAA level:

Secondary defect: 5 broken beans = 1 complete defect

Causes:

1) treatment: broken beans, broken beans or broken beans usually occur due to excessive friction or excessive pressure due to incorrect machine adjustment during pulp removal or shelling treatment.

Precautionary measures:

1) Agriculture: picking and handling only ripe fruits, because immature or immature fruits cannot correctly remove the pulp. Immature fruit cannot remove the flesh at all.

2) treatment: pay attention to adjust the pulp remover to avoid excessive pressure or friction on beans.

In the shelling plant, adjust the sheller to avoid bean friction, and use a density classifier and a size classifier to remove small broken beans or broken beans. Larger beans must be graded either by color classifier or by hand.

Defective name: unripe beans