The grading is most commonly found on specialty coffee, these types of coffee beans are a bit pricier than regular coffee beans, but the taste is really different from anything else.
This article tells you how the grading systems work and what the words mean on your coffee bag. This way, you will know when you’re buying a good-grade specialty coffee.
I’ll start by explaining Kenya’s coffee grading system, I will then go through some more information about the classification and how the size of the coffee beans have an impact on the price of your coffee bean bag
How Kenya’s coffee grading works
So let’s start with the grading of coffee beans from Kenya. This will cover the most commonly used gradings. This will make it easier to understand once we will cover more country’s.
Kenya’s grading systems are split into multiple categories, which will include the size of the beans and how many defects there are in the sample pack.
Classification by defects (washed)
- PB – Peaberries
- AA – Screens: 17 and 18 = 7.2 mm
- AB – Screens: 15 and 16 = 6.6 mm
- C – Screens: 14 and 15
- E – Elephant – when the beans separate during processing, they are chipped and called “Ears.” This category also contains large “Peaberries.”
- TT – Light beans separated from AA and AB by air current
- T – Smaller than TT, many fragments. Light beans separated from C by the air current.
- UG – Ungraded: all that does not fit the specific criteria for each official grade
Classification by defects (natural)
- M’buni – Deteriorated beans, processed by the dry method
- MH – M’buni Heavy = large beans
- ML – M’buni Light = small beans
So what does this exactly mean?
AA quality coffee beans are the best that Kenya can offer the world. These coffee beans are the biggest and have the least defects.
Peaberries, on the other hand, are sometimes named the best quality coffee beans. I have made an article where I explain what peaberries are, and you can click here to learn more.
The lower quality the coffee beans are graded at, the cheaper the price will be. Many of the smaller beans and fragments will go into pre-ground coffee, which you can buy at your local supermarket.
The reason being is because you can never find out if the pre-ground coffee beans were of good quality. You need to see the whole bean to find out if the quality is good. When the coffee is pre-ground, you won’t be able to check this.
But what do the numbers mean? The coffee beans are also screened if you want to know more about screening the coffee beans, then read along.
How are coffee beans screened?
According to Driftaway. The coffee beans are sifted through screens, which are metal sheets with specifically sized, round holes punched into them. (Screens used for peaberries have oblong holes, which more closely match peaberries’ elongated shape.)
Screens are numbered 8 through 20, with the number referring to how many 64ths of an inch the holes are. For example, a size 8 screen has holes that are 8/64 inches wide, and a size 20 screen has holes that are 20/64 inches wide.
The size of a selection is determined by passing it through screens until it doesn’t go through the next-smaller size. For instance, if a coffee passes through a size 18 (18/64 inch) screen but not a size 16 (16/64 inch wide), it’s graded to size 18.
This measurement is rarely perfect, so some leniency is allowed for larger and smaller beans. In its classification, the SCAA permits a 5-percent variance; other organizations allow similar or smaller variances.
The SCAA (Speciality Coffee Association of America) provides a standard in the green coffee classification. They differ slightly from the Brazil method when looking at the defects list.
How the size of the coffee bean is named across the world
Driftaway coffee says that coffee is sorted using the table below:
| Screen size | Inches | Industry Classification | Central and South America | Colombia | Africa and India |
| 20 | 20/64 | Very large | Elephants | ||
| 18 | 18/64 | Large | Superior | Supremo | AA |
| 16 | 16/64 | Large | Segundas | Excelso | AB |
| 14 | 14/64 | Medium | Terceras | C | |
| 12 | 12/64 | Small | Caracol | ||
| 10 | 10/64 | Shells | Caracolli | ||
| 8 | 8/64 | Shells | Caracolillo |
How does the classification of coffee beans work in Brazil?
The Brazilian method uses 300 grams of coffee to be classified. When looking at this chart, you can see the defects and how many defect points each defect is given. This will eventually determine which grading the coffee beans get.
| 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 |
| Malformed | 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 |
When taking a look at this table, you can see what defects are allowed to be in Brazil’s coffee grading. The defects list for coffee grading from SCAA only includes water damage to the list. I will explain more about what the defects exactly mean.
Sour beans and, in more extreme cases, stinker beans. Give the coffee cupping a sour, slightly whiny, acidic taste.
These sour beans are usually removed before the cupping of the coffee begins. However, sometimes they do get through, and it will give off a very different smell and taste than you are used to.
The coffee beans’ insect damage has the same sour/ stinker taste, just like the sour beans. Insects will go into the coffee cherry while ripening and kill the seed embryo, introducing the moldy/ sour smell.
So, how are the final coffee bean grades determined?
According to FAO, specialty coffee is graded in the following way:
- Specialty 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, flavor, 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, flavor, 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.
Does the grade of the coffee beans make a difference?
You will now have enough information to make an informed decision to answer this question yourself. For me, it doesn’t make a difference what coffee beans I buy. Let me explain why this is.
I have bought a lot of different coffee beans from different regions and countries. The taste of the coffee will be determent by a lot of other factors other than the grading. The processing and roaster have a big impact on the flavor, the grading not so much.
The grading system is only there to split all the produced coffee beans into different categories. I have had many bags of coffee that had no grading on it and very few who did have a Grade 1 classification. I couldn’t taste or see the difference in coffee beans.
You might get a few bad beans or broken coffee beans in your coffee bean bag from your local coffee roaster anyway. Just make sure you are not buying the lowest grading, as this will result in a lesser quality cup of joe.
Don’t be afraid to ask your coffee bar and/ or coffee roaster which coffee beans they use. You can also ask which grade this is, and you might even get to see the difference between them right there!
Conclusion
Going over all this information is tough. But you made it, and now you know what the grading on your coffee bean bag means. Does it matter for most of us? For me, it doesn’t matter. I have made great coffees using coffee beans without grading on them.
I’ve listed a few articles about coffee beans that might be of interest to you. You can check them out by clicking the links below.
That being said, do you prefer buying grade 1 coffee beans? Let me know by leaving a comment down below. If you have any other questions regarding coffee, you can also contact me directly by pressing the “Contact Me” button at the top!
