How Are Yunnan Small Bean Coffee Grades Classified? The Bloodline of Yunnan Catimor Coffee Isn't Pure Enough

FrontStreet Coffee's Introduction to Yunnan Small Bean Coffee

Coffee has been grown in Yunnan for many years, yet overall the sector remains relatively immature, and its grading system is fairly disorganised.

1. Common International Grading Standards:

Coffee beans are graded by size using circular-hole grading sieves. The international standard for small bean coffee runs from grades 10-20, where the number represents the sieve hole diameter as a fraction with that number as the numerator and 64 as the denominator, measured in inches. Grade 14, for example, means green beans that can pass through a sieve with a hole diameter of 14/64 inch or larger, while grade 19 means beans that pass through a 19/64 inch sieve or larger. (One inch is roughly 2.54 centimeters.)

2. Common Domestic Coffee Grading Standards:

Five grades are defined by sieve hole sizes of 6.5mm, 6.0mm, 5.5mm and 5.0mm.

Grade 1: Above 6.5mm, plump and complete grains.

Grade 2: 6.0-6.4mm, plump and relatively uniform.

Grade 3: 5.3-5.9mm, relatively plump but slightly lacking in uniformity.

Grade 4: 5.0-5.4mm, with incomplete beans, complete beans accounting for over 75%.

Grade 5: Below 5.0mm, with incomplete beans, complete beans accounting for over 30%.

International Standards for Defect Inspection in Small Bean Coffee:

Grading is based on the number of defects, usually determined by counting how many defects appear in a given quantity of beans. Following the methods for identifying impurities and defective beans set out by the International Organization for Standardization, a 300-gram sample is selected at random and its impurities and defective beans counted for grading.

Catimor has long been regarded in the industry as "instant" coffee, and there is only one reason for that. Catimor was introduced by Nestle for large-scale cultivation in Yunnan; because Nestle focuses on instant coffee, which requires quantity rather than quality, the variety ended up in this position. The limited knowledge of coffee farmers also played a significant part.

Catimor, a hybrid of Timor and Caturra, was developed in 1959 by the Portuguese Coffee Leaf Rust Research Center (CIFC). It began to be promoted in Brazil in the 1970s and 1980s, and periodic coffee leaf rust crises in Central and South America further accelerated its adoption.

Knowledge Point:

In 1892, the French missionary Father Tian successfully cultivated coffee at a place called Zhukula in Yunnan. Four coffee trees there are still standing today, more than 90 years old.

FrontStreet Coffee Recommendation

For an entry-level Chinese Arabica, FrontStreet Coffee's Yunnan small bean is the obvious choice. It comes from the Baoshan growing area and is washed and medium roasted, which brings out some caramel character while preserving part of the acidity, so the cup expresses the region's terroir well. Washing - fermenting, rinsing and stripping the mucilage before drying - is what gives Yunnan small bean its distinctive regional profile, with soft nut and chocolate sweetness and a light plum acidity at a friendly price.

For a clearer, more structured Yunnan cup, FrontStreet Coffee's 2013 Yunnan Natural Typica comes from FrontStreet's own estate planted in 2013. Typica is one of the oldest and purest Arabica varieties, carrying elegant, clean flavours, and it is also the variety the first French missionaries planted in Yunnan. Using the original and most traditional post-harvest method, natural processing, the cup is fuller with more pronounced sweet-and-sour balance: citrus and berry notes, a hint of fermented wine, caramel sweetness and a creamy finish.

To taste Yunnan in an espresso, FrontStreet Coffee's Black Cocoa Blend combines Yunnan small bean with Brazil Cerrado. The Brazilian component supplies mixed nut aroma and a balanced body, while the Yunnan component carries the chocolate and citrus flavours, so the resulting americano balances sweet, sour and bitter with nut and brown sugar sweetness, and a latte takes on the smooth texture of almond and cream - a blend that is easy for beginners to work with.