ANNEX 7
Green Coffee Classification and Grading
i) Speciality Coffee Association of America (SCAA) Green Coffee Classification
The green coffee classification standard provided by the SCAA is an excellent method to classify coffees. It is superior over some systems in that it better accounts for the relationship between defect and cup quality. However, it leaves out a few of the important defects that can occur in coffee (See the Brazilian Green Coffee Classification).
To classify a coffee, 300 grams of properly hulled coffee is classified according to the standards given below. 100 grams of this coffee is sorted using screens 14, 15, 16, 17, and 18. The coffee remaining in each screen is weighed and the percentage is recorded. Since classifying 300 grams of coffee is very time consuming, 100 grams of coffee is typically used. It is recommend that if the coffee is of high quality with few defects to use 300 grams. If the coffee is of a lower quality with many defects 100 grams will often suffice in a correct classification as either Below Standard Grade or Off Grade. The coffees then must be roasted and cupped to evaluate cup characteristics.
Speciality Grade (1): Not more than 5 full defects in 300 grams of coffee. No primary defects allowed. A maximum of 5% above or below screen size indicated is tolerated. Must possess at least one distinctive attribute in the body, flavour, aroma, or acidity. Must be free of faults and taints. No quakers are permitted. Moisture content is between 9-13%.
Premium Grade (2): No more than 8 full defects in 300 grams. Primary defects are permitted. A maximum of 5% above or below screen size indicated is tolerated. Must possess at least one distinctive attribute in the body, flavour, aroma, or acidity. Must be free of faults and may contain only 3 quakers. Moisture content is between 9-13%.
Exchange Grade (3): 9-23 full defects in 300 grams. Must have 50% by weight above screen size 15 with no more than 5% of screen size below 14. No cup faults are permitted and a maximum of 5 quakers are allowed. Moisture content is between 9-13%.
Below Standard Grade (4): 24-86 defects in 300 grams.
Off Grade (5): More than 86 defects in 300 grams.
Primary Defects
|
Primary Defect |
Number of occurrences equal to one full defect. |
|
Full Black |
1 |
|
Full Sour |
1 |
|
Pod/Cherry |
1 |
|
Large Stones |
2 |
|
Medium Stones |
5 |
|
Large Sticks |
2 |
|
Medium Sticks |
5 |
Secondary Defects
|
Secondary Defects |
Number of occurrences equal to one full defect |
|
Parchment |
2-3 |
|
Hull/Husk |
2-3 |
|
Broken/Chipped |
5 |
|
Insect Damage |
2-5 |
|
Partial Black |
2-3 |
|
Partial Sour |
2-3 |
|
Floater |
5 |
|
Shell |
5 |
|
Small Stones |
1 |
|
Small sticks |
1 |
|
Water Damage |
2-5 |
ii) Brazil / New York method
In the Brazilian method 300 grams of coffee is classified. The number of beans equivalent to one full defect is given below. For example every three shells counts as one full defect. On the other hand one large rock counts as five full defects. If a bean has more than one defect the highest defect is counted. For example an insect damaged black bean counts as one full defect. The table is split up into two since Brazilian legislation allows a maximum of 1% of foreign defects. After counting the number of defects use the third chart to classify the type and its point rating.
| Intrinsic Defect |
Number |
Full Defects |
|
Black bean |
1 |
1 |
|
Sour (Including stinker beans) |
1 |
1 |
|
Shells |
3 |
1 |
|
Green |
5 |
1 |
|
Broken |
5 |
1 |
|
Insect Damage |
5 |
1 |
|
Mal-formed |
5 |
1 |
|
Foreign Defect |
Number |
Full Defects |
|
Dried Cherry |
1 |
1 |
|
Floater |
2 |
1 |
|
Large Rock or Stick |
1 |
5 |
|
Medium Rock or Stick |
1 |
2 |
|
Small Rock or Stick |
1 |
1 |
|
Large Skin or husk |
1 |
1 |
|
Medium Skin or husk |
3 |
1 |
|
Small Skin or husk |
5 |
1 |
Large Rock or Stick - Screen Size 18/19/20
Medium Rock or Stick - Screen Size 15/16/17
|
Defects |
Type |
Points |
Defects |
Type |
Points |
|
4 |
2 |
100 |
49 |
5-5 |
-55 |
|
4 |
2-5 |
95 |
53 |
5-10 |
-60 |
|
5 |
2-10 |
90 |
57 |
5-15 |
-65 |
|
6 |
2-15 |
85 |
61 |
5-2- |
-70 |
|
7 |
2-20 |
80 |
64 |
5-25 5/6 |
-75 |
|
8 |
2-25 2/3 |
75 |
68 |
5-30 |
-80 |
|
9 |
2-30 |
70 |
71 |
5-35 |
-85 |
|
10 |
2-35 |
65 |
75 |
5-40 |
-90 |
|
11 |
2-40 |
60 |
79 |
5-45 |
-95 |
|
11 |
2-45 |
55 |
86 |
6 |
-100 |
|
12 |
3 |
50 |
93 |
6-5 |
-105 |
|
13 |
3-5 |
45 |
100 |
6-10 |
-110 |
|
15 |
3-10 |
40 |
108 |
6-15 |
-115 |
|
17 |
3-15 |
35 |
115 |
6-20 |
-120 |
|
18 |
3-20 |
30 |
123 |
6-25 6/7 |
-125 |
|
19 |
3-25 3/4 |
25 |
130 |
6-30 |
-130 |
|
20 |
3-30 |
20 |
138 |
6-35 |
-135 |
|
22 |
3-35 |
15 |
145 |
6-40 |
-140 |
|
23 |
3-40 |
10 |
153 |
6-45 |
-145 |
|
25 |
3-45 |
5 |
160 |
7 |
-150 |
|
26 |
4 |
0 |
180 |
7-5 |
-155 |
|
28 |
4-5 |
-5 |
200 |
7-10 |
-160 |
|
30 |
4-10 |
-10 |
220 |
7-15 |
-165 |
|
32 |
4-15 |
-15 |
240 |
7-20 |
-170 |
|
34 |
4-20 |
-20 |
260 |
7-25 7/8 |
-175 |
|
36 |
4-25 4/5 |
-25 |
280 |
7-30 |
-180 |
|
38 |
4-30 |
-30 |
300 |
7-35 |
-185 |
|
40 |
4-35 |
-35 |
320 |
7-40 |
-190 |
|
42 |
4-40 |
-40 |
340 |
7-45 |
-195 |
|
44 |
4-45 |
-45 |
360 |
8 |
-200 |
|
46 |
5 |
-50 |
>360 |
Above 8 |
iii) Commercial green coffee standards
Grade
There are 5 grades determined by bean size:
|
Grade 0 : |
beans held back by screen No. 18 (7mm holes) |
|
Grade I : |
beans passing through screen No. 18 and held back by screen No. 16 (6.3 mm holes) |
|
Grade II : |
beans passing through screen No. 16 and held back by screen No. 14 (5.5 mm holes) |
|
Grade III : |
beans passing through screen No. 14 and held back by screen No. 12 (4.7 mm holes) |
|
Grade IV : |
beans passing through screen No. 12 and held back by screen No. 10 (4mm holes) |
Category
This depends on the number of defects in a 300g sample of green coffee. The number of defects is calculated by multiplying the number of each defective character found in the sample by its penalty coefficient.
|
Defect |
Coefficient |
|
Dry damaged bean |
2 |
|
Insect attacked bean |
1/10 |
|
Cherry |
1 |
|
Large piece of wood (>3cm) |
2 |
|
Black bean |
1 |
|
Medium sized piece of wood (» 1cm) |
1 |
|
Semi-black bean |
1/2 |
|
Small piece of wood (< 1/2 cm) |
1/3 |
|
Parchment bean |
1/2 |
|
Thick skin (shell) |
1 |
|
Broken bean |
1/5 |
|
Thin skin (parchment) |
1/3 |
|
Misshapen |
1/5 |
|
Undesirable bean (unripe, quaker, flat, mouldy, sour, dry, spongy, etc.) Stones 1.5g max. per sample |
1/5 |
The different categories are defined by a maximum number of defects. For example:
Extra prime category : less than 15 defects
Prime category : 15 to 30 defects
Superior category : 30 to 60 defects
Regular category : 60 to 120 defects
Under no circumstances should the total number of defects exceed 120 for a 300g sample.
Source: http://www.coffeeresearch.org/Coffeemain.htm
