Green Coffee Grading Explained: How the Coffee Grading System Works

If you have spent any time looking at green coffee listings, you will have come across grading terms - Grade 1, AA, Supremo, Strictly Hard Bean, European Preparation, screen 15+. These are not decorative labels. They are part of the coffee grading system used at origin and along the supply chain to classify green coffee before it is traded.

The problem is that there is no single, universal grading system. Different producing countries grade their coffee differently, using different criteria, different terminology, and different scales. That can make it confusing when you are comparing coffees from Kenya and Colombia on the same page.

This guide explains how green coffee grading actually works, what the main systems are, how they differ by country, and - most usefully - what any of it means when you are choosing green coffee to buy and roast. (If you are newer to buying green coffee, our guide on how to buy green coffee covers the basics.

How is green coffee graded?

Despite the lack of a universal system, most green coffee grading comes down to the same core criteria, applied in different combinations depending on the country. The grading process typically happens at the dry mill stage - after the coffee has been harvested, processed at a washing station or dried as a natural, hulled, and sorted. It is one of the final steps before the green coffee begins its journey from origin to buyer.

Grading by screen size

This is the most visible and widely used method. Green coffee beans are passed through a series of metal coffee grading screens with holes of increasing size. Each screen size is measured in increments of 1/64 of an inch. A screen 18 bean, for example, is one that does not pass through a hole 18/64 of an inch (roughly 7.1mm) in diameter.

Coffee bean size grading matters primarily because of consistency. A batch of beans that are all roughly the same size will roast more evenly than a batch with a wide range of sizes - larger beans absorb heat differently from smaller ones, and mixing the two leads to uneven development in the roaster.

It is worth noting that bigger beans are not inherently better. Screen size is a measure of physical uniformity, not flavour quality. A beautifully clean screen 14 lot can taste far better than a poorly processed screen 18. The names given to size grades - AA, Supremo, Superior - can sound like quality judgements, but they are primarily describing physical dimensions.

Grading by defect count

This is where quality assessment gets more direct. A sample of green coffee (typically 300g or 350g, depending on the protocol) is hand-sorted under controlled lighting, and any defective beans are identified, categorised, and counted.

Defects fall into two categories. Primary defects - full black beans, full sour beans, foreign matter like stones or sticks - have a significant negative impact on cup quality. Secondary defects - partial black, insect damage, broken or chipped beans, shells - are less severe individually but add up.

Under the SCA protocol, specialty-grade coffee must have zero primary defects and no more than five secondary defects in a 350g sample. (Our dedicated guide on 'coffee defects: how to spot them and what they do' covers each defect type in detail.)

Grading by cupping score

The SCA cupping protocol scores coffee on a 100-point scale across attributes like fragrance, flavour, aftertaste, acidity, body, balance, uniformity, sweetness, clean cup, and overall impression. Coffee scoring 80 points or above is classified as specialty grade. This is the specialty coffee grading scale you will see referenced on green coffee listings.

Cupping scores are the most direct measure of what actually matters - how the coffee tastes. But they are also subjective, can vary between cuppers, and are assessed at a specific point in time. A score is useful context, but it is not the whole picture.

Grading by altitude and density

Several Central American countries grade coffee primarily by the altitude at which it was grown. The logic is sound: coffee grown at higher altitudes tends to develop more slowly in cooler temperatures, producing denser beans with more complex acid and sugar profiles. (Our guide on 'Coffee Terroir Explained: What Terroir Really Means in Coffee' explains why.)

Terms like Strictly Hard Bean (SHB) or Strictly High Grown (SHG) indicate coffee grown above a certain altitude threshold - typically 1,200m or above, depending on the country. The "hardness" refers to bean density, which is a product of altitude and growing conditions.

Key physical measurements beyond grading

Alongside screen size and defect count, green coffee is also assessed for moisture content, density, and water activity. Moisture should typically fall between 10-12% for specialty coffee - too high and the coffee is vulnerable to mould, too low and it may have been over-dried or stored poorly. These measurements feed into grading but are also critical for understanding how the coffee will behave when you roast it

Ready to roast? Start with the right beans.

Traceable, freshly imported green coffee beans for home roasters - available from 0.5kg, with the same quality we supply to professional roasters.

Shop Green Beans

Why do different countries use different grading systems?

Each producing country developed its grading system independently, shaped by its own coffee history, trade infrastructure, export regulations, and the types of coffee it grows. Colombia's system was designed by the Federación Nacional de Cafeteros to standardise a massive national crop. Kenya's system evolved through its auction system, where physical size grades help organise lots for trading. Ethiopia's numeric system reflects a need to manage an enormous diversity of regional coffees, both washed and natural, at scale.

There have been calls within the industry for a more unified global grading system, and the SCA's protocols go some way towards this. But national systems persist because they are embedded in local trade regulations, export standards, and - in many cases - law. A Colombian Supremo means something specific within Colombian coffee commerce, and changing that has legal and economic implications that go well beyond convenience for international buyers.

For you as a buyer, the practical takeaway is that grades from different countries are not directly comparable. A Kenya AA and a Colombia Supremo are both "high grade" within their respective systems, but they are graded on fundamentally different criteria. Knowing what each system actually measures helps you compare more meaningfully.

Coffee grading systems by country

Here is a summary of the main systems you are likely to encounter on green coffee listings, followed by a comparison table.

Ethiopia

Ethiopia uses a numeric system from Grade 1 (best) to Grade 5 (lowest). Grading is based on defect count and cup quality. Grade 1 and Grade 2 are considered specialty grade, with minimal defects and clean or distinctive cup profiles. Grade 3 and below are commercial grade. Ethiopian coffee is also classified by region and whether it is [washed] or [natural], which adds another layer to the description you see on a listing.

Kenya

Kenya grades primarily by bean size. The most recognised grades are AA (screen 17-18, the largest standard beans), AB (a mix of screen 15 and 16), and C (smaller). Peaberry (PB) is graded separately - these are single rounded beans rather than the usual flat-sided pair. Kenya also uses E (Elephant) for unusually large beans and T/TT for the smallest. Mbuni (MH/ML) refers to natural-processed coffee. Size grading in Kenya does correlate loosely with price and perceived quality, but it is not a guarantee of cup quality - an AB lot can easily outscore an AA from the same region.

Colombia

Colombia's system is built around bean size. Supremo (screen 17+) is the top size grade, followed by Extra and Excelso (screen 14-16). Below that, Usual Good Quality (UGQ) and Pasilla (defective or broken beans) round out the scale. The system was developed by the Federación Nacional de Cafeteros and is essentially mandatory for Colombian exports. As with Kenya, size does not automatically equal quality - an Excelso lot from a good producer can be excellent coffee.

Brazil

Brazil's system (the Brazilian Official Classification, or COB) is unusually detailed and primarily cup-quality based. Grades range from Estritamente Mole (the best - clean, balanced, no faults) through Mole, Apenas Mole, Duro, Riado, Rio, and down to Rio Zona (severely defective). Brazil also grades by screen size and defect count separately. Brazil was the first major origin to standardise grading, beginning in 1836, and its system has undergone many revisions since.

Central America (Costa Rica, Guatemala, Honduras)

Most Central American countries grade primarily by altitude. The terminology varies slightly but follows the same principle:

Costa Rica uses Strictly Hard Bean (SHB, above 1,200m), Good Hard Bean (GHB, 1,000-1,200m), and Medium Hard Bean (MHB, below 1,000m). Guatemala's SHB threshold is higher - above 1,350m. Honduras uses Strictly High Grown (SHG, above 1,350m), High Grown (HG, 1,200-1,350m), and Central Standard (CS, below 1,200m). (Understanding [why some origins favour certain processing methods] also gives useful context for how these countries approach quality.)

The altitude grades are a useful proxy for density and potential complexity, but they are not the final word on quality. A well-managed farm at 1,100m can produce better coffee than a neglected one at 1,500m.

Indonesia

Indonesia uses a numeric defect-based system similar in structure to Ethiopia's, with Grade 1 being the cleanest. However, Indonesian coffees - particularly Sumatran wet-hulled (Giling Basah) lots - are often graded more leniently for certain defect types that are inherent to the processing method. This is one of those cases where understanding the processing matters as much as the grade.

Coffee grading systems compared

The key thing this table shows: most country-level grading systems measure physical characteristics (size, altitude, defects) rather than cup quality directly. The SCA scoring system is the only widely used standard that puts cupping score at the centre. This is why you often see both a country grade and an SCA score on a green coffee listing - they are measuring different things.

What is European Preparation?

You may see "EP" or "European Preparation" on green coffee listings. This is not a country-specific grade but an additional preparation standard applied before export, primarily for the European market.

European Preparation means the coffee has been more thoroughly screened and hand-sorted to remove defects, with tighter tolerances than standard preparation. Specifically, it typically means no more than 8 defects per 300g sample (compared to higher allowances in standard preparation) and removal of beans below screen 15.

For buyers, EP is a useful signal that the green coffee has had an extra level of physical sorting. It does not guarantee specialty-level cup quality - that still depends on cupping - but it does mean fewer visible defects and better size consistency, which translates to more even roasting. 

What does the specialty coffee grading scale actually mean?

The SCA's 100-point specialty coffee grading scale is the closest thing the industry has to a universal quality measure, and it is worth understanding what it does and does not tell you.

Coffee scoring 80-84 points is considered specialty grade. 85-89 is excellent. 90+ is outstanding - these are exceptional coffees that typically command significantly higher prices. Below 80 is commercial grade.

The score is the sum of individual attribute scores (fragrance/aroma, flavour, aftertaste, acidity, body, balance, uniformity, clean cup, sweetness, and overall), each marked out of 10 by a trained cupper.

What the score tells you: this coffee was evaluated by a qualified professional and found to meet a certain quality threshold at a specific point in time.

What it does not tell you: how it will taste to you personally, how it will behave in your roaster, or [how long the green coffee will last] at that quality level in storage. Cupping scores are useful benchmarks, but they are starting points for your own evaluation, not substitutes for it.

What does green coffee grading mean when you are buying?

If you are buying green coffee to roast at home or commercially, here is what is actually worth paying attention to.

Grade tells you about physical quality, not necessarily cup quality. A Kenya AA or a Colombia Supremo tells you the beans are a certain size. That is useful for roast consistency, but it does not promise a great-tasting cup. An SCA cupping score is a more direct indicator of what you will taste, though it is still one person's assessment at one moment.

Defect count matters more than most people think. Even a few primary defects - a full black bean, a sour bean - can noticeably affect the cup. If you are buying from us, we have already screened for this. If you are buying elsewhere, understanding what the defect count on a listing means helps you set expectations. (More in our guide to 'Green Coffee Defects: How to Spot Them and What They Do'.)

Higher grade does not always mean higher price is justified. A Grade 1 Ethiopian and a Grade 2 from the same region and producer may score very similarly on the cupping table. The price difference may not reflect a meaningful difference in what you taste. 

Screen size affects your roasting. If you are comparing two coffees and one is screen 15 while the other is screen 18, they will behave differently in the roaster. The larger, denser beans will need more energy to develop. If your green coffee listing includes screen size, factor that into your roast planning. 

Grading is a snapshot, not a guarantee. Coffee is graded at a specific moment - usually at export. Over time, quality can change depending on how the green coffee is stored. A coffee that graded beautifully six months ago may not cup the same way today if storage conditions were poor.

Wrapping up

Green coffee grading can look complicated, and the lack of a universal system does not make it easier. But once you understand what each system is actually measuring - size, defects, altitude, cup quality, or some combination - the terminology starts to make sense.

The most important thing to remember is that no single grade tells the whole story. Physical grades tell you about consistency and sorting. Cupping scores tell you about flavour. Together, they give you a much clearer picture of what you are buying. And when something on a listing does not make sense, ask - that is what we are here for.