The standard of SCAA pecialty Coffee boutique coffee raw beans is necessary for a good cup of coffee.

SCAA green bean defects can be divided into two categories: Class I and Class II.

The requirements for boutique coffee grade (specialty coffee) are:

1. No Class I defects

two。 No more than 5 II class defects

3. There can be no "quaker" (0 quaker) Quick beans in cooked coffee beans.

4. The color range of raw coffee beans is pale yellow (light yellow), yellow-green (yellowish green), greenish (partial green), green (green), bluish-green (bluish green) and blue-green (blue green). The color of raw coffee beans defined by SCAA can be divided into brownish light brown, yellowish yellow, pale yellow light yellow, yellow-green yellow green, greenish green, green green, bluish-green bluish green, blue-green blue green, (among them, lighter yellowish yellow and brownish brown can not be regarded as specialty grade boutique grade).

5. There's no smell.

[grading standard]

The sample quantity is: raw bean 350g, cooked bean 100g.

Defect standard

Here are some things to note:

Full Defect Equivalents The number of particles in the deduction unit meets different conditions for different defects. (For example: a whole black bean, one is counted as a Class I defect, two are counted as two Class I defects; severe insect infestation is 5 for a unit count, if less than 5 is not counted as a Class I defect, if 5 or more but less than 10 are found, then it is counted as a Class I defect, and so on; in Class II defects, local acid or local black beans are 3 units, while slight insect infestation is 10 units, and the rest are 5 units.)

Moisture content: The moisture content of coffee treated by washing method is between 10-12%.

Bean size: This means that there can be no more than 5% of the contract specifications of the size of the discrepancy;

Consistency of baking: Based on the baking standard of 100g sample, no quaker is allowed.

Grading supplement: If two or more defects occur at the same time, the more serious one will be treated. (For example, if there are local sour beans, but there are also 2 wormholes, then it must be classified as a defect of local sour beans)

Flavor characteristics: In the cup test of the sample, the beans should be able to exhibit the flavor characteristics of the region, including dry and wet aromas, acidity, body, aftertaste (finish) and overall character.

The following is a single description of each defect (Class I and Class II).

[black beans]

Physical characteristics: the most remarkable thing about black beans is that their appearance is opaque black.

Classification and defect score: black beans are divided into total black beans and local black beans according to the proportion of black beans in the whole coffee bean. (the difference between total black and local black: if the black area is less than half of the bean body, it will be treated as a local black bean, otherwise it will be treated as an all-black bean.)

One full black counts as a Class I defect.

Three local blacks count as an II defect.

Effect on the taste of the cup: SCAA describes an uncomfortable fermentation or odor, dirty, moldy, sour and phenolic smell. What I used to drink was a disgusting, uncomfortable sour and bitter smell, as well as the smell of phenol, like hospital disinfectant.

Other problems: octreotide A, which is harmful to the liver and kidneys, has been reported to degrade 80% of the toxin after baking (200 degrees Celsius), but pick it out as much as you can.

Cause of defect: this kind of defect is produced in planting, and there are many causes.

Due to infection by an organic pathogen, Colletotrichum coffeanum. The origin was found in Africa. At present, there are also cases in Central and South America.

Insufficient water supply of coffee fruit during ripening period, affecting plant metabolism.

Picked unripe beans are dried at high temperature (above 30 degrees Celsius)

Avoid and improve:

Planting: select ripe coffee fruits, improve the farming environment and methods, avoid creating a suitable environment for Colletotrichum coffeanum, improve ventilation, and clean up the stagnant water around coffee trees in a timely manner.

Treatment: black beans (after shelling) are smaller and lighter than normal beans, so black beans can be screened out by size screening and specific gravity screening in post-processing, and the most effective way is hand selection (the color of black beans after parchment removal is very easy to identify), or mechanical color selection.

[sour beans]

Physical characteristics: the appearance color of sour beans is similar to yellowish brown or reddish brown. It is usually black at the endosperm point (the position pointed to by the arrow). When you cut the beans, you can smell the sour smell of acetic acid.

Classification and defect score: sour beans are divided into two categories: total sour beans and local sour beans, the difference method is similar to black beans, if less than half of the beans belong to local sour beans, otherwise they are all sour beans.

1 the whole sour bean is a kind of I

Three local sour beans can be regarded as an II defect.

Effect in the cup: overfermented sour taste (nausea).

Cause: the main cause of sour bean is excessive fermentation. If the environment around the coffee is relatively humid, the ripe coffee fruit will ferment too much if it is not picked in time on the tree; if the picked coffee fruit is stored for too long and not treated in time, it will also be overfermented; the fermentation pool will be dirty in washing, or dirty with water will also cause sour beans; when drying, if the coffee fruit dries slowly, coupled with improper stacking, it will also cause excessive fermentation of coffee fruit and form sour beans.

Avoid and improve:

Planting: in planting, you can stop harvesting coffee fruits that have fallen on the ground by harvesting ripe fruits (avoiding over-ripe coffee fruits), and do not grow coffee at low latitudes near water sources such as rivers, lakes or reservoirs.

Treatment: timely treatment of the picked coffee fruit to avoid excessive fermentation in storage; soaking time in the fermentation tank should be reasonably controlled; water in the washing process should be changed in time to avoid recycling; the drying process should be reasonably controlled; most sour beans can be removed by hand and color selection.

[mildew bean]

Physical characteristics: the color of moldy beans is a bit like sour beans, yellow or reddish brown, but an obvious difference is that moldy beans will have a small dent, a little white powder in the spot, these powders are mold spores, very easy to interfere with other raw beans.

Classification and defect score:

One moldy bean counts as a Class I defect.

Influence in the cup: moldy soil flavor, phenolic flavor. Personal feeling is similar to black beans, the taste of miscellaneous soil in the mouth is more obvious, similar to eating a bad fried melon seed, the mouth has an obvious sense of rough gravel and bitter taste. Like black beans, there is a risk of the physiological virus of octreotide A.

Cause: moldy beans may be caused by planting and post-treatment. The mold that causes moldy beans may breed and infect raw coffee beans under certain temperature and humidity conditions.

Avoid and improve:

Planting: the premise of mold growth of moldy beans is spores, and limiting spore production is the key to avoid mold growth. In planting, avoid harvesting coffee fruits that fall to the ground, and avoid leaving raw coffee beans in harvest baskets and drying cylinders.

Treatment: raw coffee beans cut in the process of pulp (skin) removal are more likely to be infected with mold, improper fermentation control, drying is not timely or drying halfway to stop or drying cycle lengthening and other inappropriate treatment methods will make raw coffee beans have a chance to be infected with mold. In addition, shell beans are more likely to be infected with mold if they are stored at higher temperature and humidity. Therefore, the production of moldy beans can be avoided to a great extent by properly adjusting the treatment and storage methods. Color selection can remove most of the serious moldy beans, while mild moldy beans must be selected by hand to effectively remove them.

[foreign impurities]

Physical characteristics: if it is a large volume of foreign objects are relatively easy to distinguish from the appearance, but such as pebbles are generally difficult to quickly identify from raw beans, only with the help of auxiliary equipment to remove impurities, to avoid the risk of impact on the baking machine and bean grinder.

Classification and defect score:

A foreign object counts as a Class I defect.

Influence in the cup: some foreign substances will affect the raw beans and cause the defective taste in the cup.

Other effects: the more direct impact of foreign objects is on roasters (rollers) and bean grinders (cutters), such as pebbles.

Cause: foreign matter may be introduced into beans at all stages of the treatment process (mostly due to human reasons).

Avoid and improve:

In the treatment stage, we should pay attention to avoid introducing sundries such as small stones and branches when picking; when drying naturally on the scaffolding, we should also be careful to avoid introducing foreign objects such as stones, wood strips, and so on; in the process of removing shells after drying, use a stone removal machine, magnets can effectively remove stones, metals and other foreign objects.

[dried pods]

Physical characteristics: large dried pods are generally the whole coffee fruit is not removed from the raw beans after drying, the volume is much larger than raw beans, and the appearance color will be yellowish brown to dark red; and if drying or improper storage and transportation conditions will be more likely to infect mold and affect other raw beans.

Classification and defect score:

A dried pod counts as a Class I defect.

Effects in the cup: fermentation, mildew and phenolic flavor.

Causes:

Treatment: during washing, the peel is removed improperly (the peeling machine is improperly set up or the aging machine makes the dried pods pass directly), or the floating dried pods are not removed in the first step of rinsing. During sun treatment, improper shelling and screening also have the chance to miss some dried pods.

Planting: drought and disease can dry the coffee fruit on the tree and eventually fall to the ground.

Avoid and improve:

Planting: avoid picking dried coffee fruits that fall to the ground, and avoid picking dried coffee fruits from trees.

Treatment: avoid too many dried pods mixed with raw beans to shell together, because too many dried pods will also cause the sheller to be unable to effectively handle the dried coffee, thus missing part of the dried pods; the floating beans should be completely removed at the beginning of washing. Regular correction and maintenance of peeling machine to effectively remove peels and dried pods. The missing dried pods can be removed by weighing machine in the process of shelling after drying.

[worm-eaten beans]

Physical characteristics: borer beans will be found on the appearance of small holes (diameter 0.3-1.5 mm), and because worms drill in and out there are usually holes on both sides, serious wormholes sometimes several small holes together, and like damaged beans because the bean body is damaged, it is easy to oxidize and become infected with mold in the worm-eaten area.

Classification and defect score: serious and slight moth-eaten.

Serious wormeaten: there are 3 or more wormholes in the bean body, which is a Class I defect when there are 5 serious wormeaten beans.

Light wormeaten: less than 3 wormholes in the bean body, which is considered an II defect when there are 10 slight wormeaten beans.

Influence in the cup: dirty taste, sour taste, phenolic taste and musty taste.

Cause: worm-eaten beans are produced in the process of planting. The coffee beetle will drill into the coffee beans to lay eggs, and then the eggs will parasitize in the coffee beans and absorb the nutrients of the coffee beans. Wormholes in wormeaten beans usually appear in pairs (in and out).

Avoid and improve:

Planting: be careful in disease and pest quarantine and eliminate all conditions beneficial to coffee beetles as soon as possible; drug spraying is also a way, but the effect is limited. At present, more producing areas use new technologies, such as traps and natural enemies of coffee beetles, to kill pests more effectively. Because the coffee beetle is inside the coffee bean fruit and coffee beans, coffee farmers are unable to distinguish between worm-eaten coffee fruit and normal coffee fruit when picking. The increase of planting altitude will significantly reduce the effect of coffee beetles.

Treatment: moth-eaten coffee beans can be clearly identified after shelling. Most of the serious worm-eaten beans can be eliminated by weighing machine. If the worm-eaten infection is more serious, it must be eliminated by hand.

[damaged beans and cut beans]

Physical characteristics: the appearance of raw beans shows mechanical damage wounds such as rupture and fragmentation, and sometimes the edges are black.

Classification and defect score

Five broken beans are counted as an II defect.

Effect in the cup: if there is mildew, there is obvious soil mildew, dirty taste, sour taste and fermented taste.

Cause: improper training of peeling machine or shelling machine in the process of treatment leads to extrusion injury or cut of beans.

When washing, the crushed mouth injured in the peel removal process is more likely to be infected with mold and oxidation, generally turning dark reddish brown or black.

Sun treatment of the broken mouth is generally caused by the shelling of dried fruit, generally relatively clean without signs of oxidation.

Avoid and improve:

Planting: avoid picking unripe coffee fruits.

Treatment: carefully train the peeling machine and sheller; small broken beans can be removed by weight machine and screen, while large broken beans can be removed by color selection and hand selection.

[uncooked beans]

Physical characteristics: the remarkable feature of unripe beans is that the silver skin is tightly attached. Unripe beans are usually smaller than normal raw beans, with concave bodies and sharp edges. Another name for unripe beans is QUAKER in roasted coffee beans, because raw coffee beans are not fully ripe, resulting in inadequate absorption of sugar, so the caramelization (coloring) during baking is not sufficient, resulting in a much lighter color than normal beans.

Classification and defect score: 5 unripe beans are counted as one II defect.

Influence in the cup: grass flavor, straw flavor.

Cause: unripe beans are produced in the process of planting, such as improper picking and planting late-ripening coffee varieties at high altitudes.

Avoid and improve:

Planting: improve the picking quality, pick only ripe beans, and plant suitable mature varieties according to altitude.

Treatment: because the flesh (skin) of unripe beans binds to coffee beans more closely than normal mature coffee fruits, so in peeling, only a small part of the peel of immature beans will be removed, and even the whole coffee fruit will be omitted. Immaturity can be removed quickly through a sieve. After drying, the unripe beans can also be removed by the weighing machine; it should be noted that because there is no obvious difference between the unripe beans and the normal raw beans in color, it can not be removed with the color sorter.

[atrophic beans]

Physical characteristics: shrunken beans are smaller than normal beans, and the most significant is the dehydrated wrinkle, similar to raisins (can be associated with the wrinkle of the skin after soaking in water for a long time).

Classification and defect score: 5 shrunken beans were counted as one II defect.

Influence in the cup: slight smell of grass, straw.

Cause: shrunken beans are only produced in the process of planting, mostly due to the stunted development of coffee trees caused by drought, unable to transport the necessary nutrients to the coffee fruit.

Avoid and improve:

Planting: reasonable fertilization to ensure the healthy growth of coffee trees; too many or inappropriate shade trees may also cause competition for water with coffee trees.

Treatment: seriously shrunken beans are light and float directly on the water surface during washing treatment, so it is easier to carve them out; when shelling, most of the remaining shrunken beans can be removed by weight machine. Individual large or thick shrunken beans have to be removed by hand.

[Shell beans]

Physical characteristics: shell beans have two parts, the outer part is commonly known as "shell" shape, the inner part is either conical or cylindrical. Sometimes, the two parts of the shell bean in the raw bean are still closely attached together. In this case, it is counted as one shell bean, and if they have been separated, they are counted as two. Most shell beans separate into two parts after baking, and the lighter outer part of the shell is more likely to burn.

Classification and defect scoring: 5 shell beans count as a Class II defect.

Effect in the cup: burnt smell (due to the low density of shell beans, it is very easy to be burnt or even burned by the high temperature during baking)

Cause: Now research believes that shell beans are mostly caused by variety genes.

Avoid and improve:

Planting: Select the right coffee varieties to grow and optimize the growing conditions.

Treatment: When shelling, remove shell beans using a specific gravity machine.

[floating beans]

Physical characteristics: floating beans are much lighter and whiter than normal beans, and they float when they are put in water.

Classification and defect score: 5 floating beans are counted as one II defect.

Influence in the cup: according to the degree, there are fermentation flavor, green grass flavor, straw flavor, soil flavor, mildew taste and so on.

Cause: improper storage and drying are the main causes of floating beans. Shell beans usually lead to floating beans if they are left in a dryer or on a drying scaffolding. Storage with shell beans and an environment with high humidity can also cause floating beans.

Avoid and improve:

Treatment: shelled beans must be evenly dried to a certain water content, so that the production of floating beans can be avoided. After shelling, low-density floating beans can be removed by gravimetric machine, while high-density floating beans are not much different from normal beans in weight, so they can only be picked out by color selection or hand selection.

[Shelled beans]

Physical characteristics: Shelled beans are generally fully or partially covered by parchment shells, and the appearance (shell) color is khaki.

Classification and defect scoring: 5 shelled beans count as a Class II defect.

Effect in cup: woody. (If the proportion of shelled beans is large, the woody smell will be obvious)

Cause: mainly in the drying process of peeling, if the peeling machine aging or improper adjustment will cause leakage of beans with shells.

Avoid and improve:

Treatment: Check and correct the sheller before shelling. The separated shells (parchment) can be removed with a densitometer.

[peel and shell]

Physical characteristics: peel or shell usually appears as fragments in raw beans, and the appearance color is black and red (like the color of dried raisins).

Classification and defect score: 5 pericarp (shell, or exocarp) is counted as an II defect.

Effect in the cup: if the pericarp is infected by mold in the cup, it will have a dirty, earthy, moldy, fermented or phenolic taste.

Cause: mainly in the treatment stage, the lack of careful cleaning of raw beans after shelling will lead to residual shells. If the peeling machine is not properly adjusted in the process of peeling in water washing treatment, it will also cause the peel to be broken and eventually become shell fragments after drying.

Avoid and improve: train the peeling machine; pay attention to the process of wind selection and specific gravity selection, do not miss the fruit shell.

Source: Brista blog