Pick up a bag of single-origin beans and you will often find a short code stamped near the origin: Colombia Supremo, Kenya AA, Guatemala SHB, or Brazil Santos, Type 2, screen 17/18. Those labels are the shorthand of coffee grading — the classification systems that producing countries use to sort raw, unroasted green coffee long before it reaches a roaster. Grading turns a warehouse full of beans into consistent, tradeable lots, and it gives buyers a common language for describing what is in the bag.
The catch is that no two origins grade coffee quite the same way. Some countries sort by the altitude a coffee was grown at, some by the physical size of the bean, some by counting defects, and the best specialty programs finish by tasting the coffee and scoring the cup. This guide walks through each of those axes, lays the main national systems side by side, and — just as importantly — explains why a fancy grade on the label is a useful clue about quality rather than a cast-iron promise. If you are new to the wider world of the bean, our coffee hub is a good place to start.
What coffee grading actually measures
Strip away the local vocabulary and almost every national scheme is built from the same three ingredients. Once you can see them, any grade on any bag becomes readable.
- Altitude and bean hardness. Coffee grown on cool, high mountain slopes ripens slowly and matures into a denser, harder seed. Central American countries turn this into grades such as Strictly Hard Bean or Strictly High Grown.
- Bean size and shape. Green coffee is shaken over stacked perforated screens so that larger beans are separated from smaller ones. Kenya's AA, Colombia's Supremo and Brazil's screen numbers all describe size.
- Defects and cup quality. Graders count physical defects in a fixed-weight sample and, in specialty programs, taste the coffee and award a numerical score. This is the only axis that measures flavor directly.
Most real-world grades combine two or three of these. A Kenyan lot marked "AA" has passed a size screen; a Honduran "SHG EP" tells you both the altitude band and that the coffee is European Preparation — hand-sorted to remove defects. The rest of this article takes each axis in turn.
Grading by altitude: SHB, HB, SHG and HG
The most common thing a Central American grade tells you is how high the coffee grew. Cooler air at elevation slows the ripening of the cherry, and slower ripening tends to build more sugars and acids while producing a denser, harder bean. Because density rises with altitude, many countries simply grade by hardness and let it stand in for elevation.
Two dialects describe the same idea:
- Hard Bean grades — used in Guatemala and Costa Rica. SHB (Strictly Hard Bean) is the top tier, roughly coffee grown above about 1,350 m in Guatemala and above about 1,200 m in Costa Rica, with HB (Hard Bean) and softer grades below it.
- High Grown grades — used in Mexico, Honduras, El Salvador and Nicaragua. SHG (Strictly High Grown) generally means above roughly 1,200 m — though several countries, Honduras among them, draw the line higher still — with HG (High Grown) covering the band just below it.
"Strictly Hard Bean" and "Strictly High Grown" are effectively two names for the same premium altitude class — the exact metre thresholds shift from country to country, so treat them as bands rather than hard borders. Altitude is one of the most reliable proxies for potential quality, but it is only potential: what actually happens to acidity, sweetness and density as beans climb is covered in our guide to altitude and coffee.
Grading by bean size: screens, AA/AB and peaberry
The other workhorse of coffee grading is size. Beans are passed over a series of metal screens perforated with round holes measured in 1/64 of an inch: a "screen 18" bean is one that will not fall through an 18/64-inch hole, a "screen 16" is smaller, and so on. Larger, denser beans are often — though not always — a sign of mature cherries from healthy trees, which is why size became a grading shortcut across East Africa and the Americas.
Kenya runs the best-known size system. From largest to smallest, the main grades are E (Elephant, the very biggest), AA (about screen 17–18), AB (a blend of the A and B size classes, roughly screen 15–17, and the backbone of most Kenyan lots), PB, then smaller grades such as C, TT and T. Crucially, AA is a size grade, not a taste grade — Kenya's celebrated cup quality comes from its varieties, soils and processing, not from the two letters alone, as our guide to Kenyan coffee explains.
PB stands for peaberry. Normally a coffee cherry holds two seeds that grow flat-sided against each other; in a peaberry, only one seed develops and it grows into a small, rounded bean. Peaberries occur naturally in a small share of any crop and are screened out and sold separately, partly because their rounder shape roasts differently from flat beans. They are often marketed as more concentrated in flavor, though whether they truly taste better is debated rather than settled.
How the major origins name their grades
Because each country built its system independently, the same idea wears different clothes from one origin to the next. The table below lines up the flagship systems so the vocabulary is easier to translate.
| Origin | Graded mainly by | Flagship / top grades | Worth knowing |
|---|---|---|---|
| Kenya | Bean size (price set by cup) | AA, AB, PB, then C / TT / T | AA and AB are size classes; a separate auction cup score sets the real value. |
| Colombia | Bean size | Supremo (screen 17–18), Excelso (screen 14–16) | Supremo and Excelso can come from the same farm — even the same tree. |
| Brazil | Defect count + screen + cup | Type 2 (fewest defects) down to Type 8; "Santos" fine cup | Based on the historic New York (NY) scale; Type 2 is the top practical grade. |
| Central America | Altitude / hardness | SHB, HB (Guatemala, Costa Rica); SHG, HG (Mexico, Honduras, El Salvador, Nicaragua) | "EP" (European Preparation) signals extra hand-sorting for defects. |
| Ethiopia | Defects + cup, split by process | Grade 1 and Grade 2 lead; the scale runs to G9 | Washed and natural coffees are graded on different defect thresholds. |
Colombia keeps it purely about size: Supremo is the large-screen export grade (roughly screen 17–18) and Excelso is a notch smaller (about screen 14–16). The two can be sorted from the very same lot, which is the clearest reminder anywhere that a size grade is not a quality verdict — see our Colombian coffee guide for how the country's regions fit in. Brazil, the world's largest producer, historically leaned on the New York (NY) type scale, which ranks coffee by the number of full defects in a 300-gram sample, from Type 2 at the top down to Type 8, and pairs it with screen size and cup terms such as "Strictly Soft." A classic descriptor like "Santos NY 2, 17/18, fine cup" is really three grades stacked together, as our Brazilian coffee guide unpacks. Ethiopia grades on defects and cup quality through its national coffee authority, running from Grade 1 down to Grade 9 — roughly the first two grades form the export elite — and it grades washed and natural coffees on different defect scales because the two processes look completely different in the green.
Specialty grade and the 80-point line
The systems above all try to predict quality from physical clues. The Specialty Coffee Association (SCA) added the axis that measures it directly: a standardized green grade plus a cup score. To qualify as Specialty Grade (Grade 1), a green sample must have no more than five full defects in 350 grams, contain zero "primary" (category-one) defects, stay within tolerance on screen size and moisture, and show at least one distinctive positive attribute in aroma, flavor, acidity or body. Then trained cuppers taste it, and it must score 80 points or more out of 100 on the SCA protocol.
That 80-point line is the modern definition of "specialty," and it is the one grade on this page that is built on flavor rather than a stand-in for it. We keep the deep dive — the score categories and where exactly the line sits — in our guide to what specialty coffee means. The mechanics of how defects are actually counted and weighted, and how graders sort primary from secondary defects, live in our dedicated coffee defects guide, so we do not double up on the counting method here.
Why a grade is a proxy, not a promise
Here is the honest part. With the single exception of a cup score, every grade on this page describes the body of the bean, not its flavor. A screen-18 AA bean can be large and beautiful and still cup flat if the cherries were picked unripe or a ferment went wrong. A tiny C-grade or a humble peaberry from a great farm can outshine it. Altitude, hardness and size correlate with quality because the conditions that grow big, dense, high-grown beans often also grow good coffee — but correlation is not a guarantee.
This matters because size and altitude grades are also the easiest to lean on in marketing. "AA" and "Supremo" sound like taste awards; they are really sorting categories. The most reliable signal a bag can carry is a transparent cup score against a known protocol, ideally alongside the farm, variety, process and harvest year. Read the size and altitude grade as a helpful starting hypothesis, then let the cup — and increasingly, details like processing and moisture — settle the argument. Grading gets coffee onto the same page; tasting is still what decides the winner.
Frequently asked questions
How is coffee graded?
Green coffee is graded before export using a mix of measures: the altitude or hardness it grew at, the physical size of the bean sorted over perforated screens, the number of defects counted in a fixed sample, and — in specialty programs — a cupping score. Each producing country combines these differently, so a single label such as "Kenya AA" or "Guatemala SHB" can encode size, altitude, or both. The only axis that measures taste directly is the cup score.
What does AA mean in coffee?
AA is a bean-size grade, used most famously in Kenya, for beans that sit around screen 17–18 (about 17–18/64 of an inch) — the large end of a normal lot. On its own it says nothing about flavor; it simply means the beans are big and uniform, which helps them roast evenly. Kenya's reputation comes from its varieties, soils and processing, so treat AA as a size class rather than a quality certificate.
What is SHB and SHG coffee?
SHB (Strictly Hard Bean) and SHG (Strictly High Grown) are the top altitude grades in Central America — SHB in countries such as Guatemala and Costa Rica, SHG in Mexico, Honduras, El Salvador and Nicaragua. Both describe coffee grown high on cool mountain slopes, generally above roughly 1,200–1,350 metres, where slow ripening yields a denser, harder bean. The exact altitude threshold shifts from country to country, so read them as bands, not fixed lines.
What is the difference between Supremo and Excelso?
Both are Colombian export grades based purely on bean size. Supremo is the larger screen (roughly 17–18), while Excelso is a step smaller (about screen 14–16). The two can be sorted from the very same farm — even the same tree — so the difference is size and uniformity, not origin or inherent quality.
Does a higher grade mean better-tasting coffee?
Not necessarily. Grades based on size or altitude — AA, Supremo, SHB — are proxies: the conditions that produce big, high-grown beans often correlate with good coffee, but a large bean can still cup poorly and a small one can be excellent. The only grade that measures flavor directly is a cupping score, such as the SCA's 80-point specialty threshold. Use size and altitude grades as clues, and let the cup decide.