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Yunnan Specialty Coffee Bean Grading System and Flavor Profiles: A Guide to Yunnan Arabica Coffee Brands

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, For professional coffee knowledge and more coffee bean information, please follow Coffee Workshop (WeChat official account: cafe_style). Although Yunnan has been cultivating coffee for many years, the industry is still relatively immature. Its grading system remains quite disorganized. 1) Common international grading standards: Based on coffee bean size, using round-hole sieves

As agricultural products, coffee beans cannot achieve uniform standards like industrial products. Variations in size and quality are normal phenomena. Therefore, every country that grows coffee beans establishes unified grading standards to regulate the quality of coffee beans, while also providing a value reference for green bean traders and purchasers. FrontStreet Coffee would like to discuss the grading system of Yunnan coffee beans with you in this article.

So, does Yunnan coffee bean grading actually have standards? Are there any guidelines? The answer is yes. Currently, the grading standards for Yunnan green coffee beans refer to the "Green Coffee Grade Inspection Standards" released by the Yunnan International Coffee Exchange Center in 2019.

However, these grading standards have not been well promoted. Many businesses mostly adopt their own "self-assessment standards," based on bean size or altitude, defining their coffee bean grades according to the "advantages and characteristics" of their production areas. Some even directly reference foreign grading standards, such as Kenya's AA, AB, etc. Recently, some estates have even introduced "AAA" grade beans, and "4A grade" might appear soon. This market chaos results in grades that differ greatly from actual taste and flavor profiles. Currently, the international specialty coffee market has not yet recognized Yunnan coffee.

Currently, Yunnan coffee generally uses particle size + defect rate for grading. Particle size is based on international standard mesh numbers. Meanwhile, international defect bean point standards, bean appearance and color, cleanliness, aroma, moisture content, and other factors are also referenced.

International Coffee Grading Standards

Coffee beans are graded by size using round-hole sorting screens. International standards for small-bean coffee have grades 10-20, where the numbers represent screen hole diameters as fractions with the number as the numerator and 64 as the denominator, in inches. For example: Grade 14 means green coffee beans that can pass through screens with 14/64 inch hole diameters, while Grade 19 refers to green coffee beans that can pass through screens with 19/64 inch hole diameters. (1 inch ≈ 2.54 centimeters)

Domestic Coffee Grading Standards

Divided into five grades based on screen hole diameters of 6.5, 6.0, 5.5, and 5.0 millimeters.

Grade 1: Above 6.5mm, plump and complete particles.
Grade 2: 6.0-6.4mm, plump, relatively uniform.
Grade 3: 5.3-5.9mm, relatively plump, slightly less uniform.
Grade 4: 5.0-5.4mm, with incomplete grains, complete grains accounting for over 75%.
Grade 5: Below 5.0mm, with incomplete grains, complete grains accounting for over 30%.

International Standards for Defect Inspection of Small-Bean Coffee (Arabica)

Grading is based on the number of defects, often determined by counting how many defects are present in a certain amount of coffee beans. According to the inspection methods for impurities and defective beans specified by the International Organization for Standardization, a 300-gram coffee bean sample is randomly selected, and the impurities and defective beans are counted for grading.

Yunnan Small-Bean Coffee Varieties

Careful readers may have noticed that FrontStreet Coffee just mentioned that small-bean coffee actually refers to Arabica coffee beans. In the Coffea genus of the Rubiaceae family, various coffee varieties are mainly divided into three major species: Arabica, Robusta, and Liberica. Arabica beans are smaller than other species, so people historically called Arabica coffee "small-bean coffee" or "small-fruit coffee."

Yunnan small-bean coffee was originally named for Typica, because Typica is an Arabica small-bean variety. The oldest coffee variety in Yunnan is Typica. Later, when Nestlé entered Yunnan, due to Typica's poor disease resistance and to increase coffee bean yields, coffee farmers were asked to cut down flavorful Typica coffee trees and plant varieties with inferior flavor but better disease resistance and higher yields. Initially, the leaf rust-resistant S288 was introduced, and later the higher-yielding Catimor was introduced. This means that the coffee trees currently planted in Yunnan are mainly Catimor varieties.

Compared to Typica varieties, Catimor coffee may be somewhat lacking in flavor. However, with the promotion of specialty coffee culture, Catimor coffee in Yunnan has received more scientific cultivation and planting, and its flavor and quality have greatly improved.

To let everyone experience the charm of Yunnan Typica, in 2013, FrontStreet Coffee began planting Typica varieties and a small amount of Bourbon varieties in Lincang, Yunnan, for research and experimental planting. After harvest, these are sold online and in FrontStreet Coffee's physical stores, named "Frontsteet 2013 Natural Typica Coffee Beans." The flavor is cleaner, with balanced sweet, sour, and bitter notes, and a noticeable aftertaste.

Additionally, two Catimor coffee beans from the Baoshan region of Yunnan have been selected. "FrontStreet Coffee - Baoshan Washed Catimor Coffee Beans" serve as a selected daily coffee from the region, allowing consumers to taste the Yunnan region's nut, caramel, and plum-like flavor characteristics at the highest value for money.

"FrontStreet Coffee - Baoshan Full Red Cherry Natural Catimor Coffee Beans" are made from 100% full red cherries using natural processing. They have higher sweetness than washed Catimor coffee beans, with soft red berry acidity.

How to Brew Yunnan Small-Bean Coffee

Dripper: Hario V60
Water Temperature: 90 degrees Celsius
Coffee Amount: 15 grams
Coffee-to-Water Ratio: 1:15
Grind Size: 75% pass-through rate on China standard #20 sieve

First, pour 30 grams of hot water and let it bloom for 30 seconds. Starting from the center, pour in a fine stream and slowly circle to 125 grams for分段 (segmented pouring). Wait until the water level in the dripper drops to just above the coffee bed, then continue circling and pouring to 225 grams. Total extraction time is approximately 2 minutes.

When shipping, FrontStreet Coffee ensures that the coffee beans delivered to everyone's hands are freshly roasted within 5 days. By the time you receive them, they have already undergone a 4 to 7-day degassing period, and their flavor is at its best. FrontStreet Coffee has also noticed that some friends choose to have Frontsteet grind the coffee for them due to the high fine powder rate of their home grinding equipment. It's important to note that once coffee is ground into powder, the volatilization rate of flavor compounds accelerates.