What You Should Know About Coffee Beans

When you take a sip of your favorite coffee, have you ever wondered where those dark, fragrant beans actually come from? Most people recognize the small, round, deep-brown beans that release a rich aroma when ground and brew into a golden amber cup—but there’s much more behind that simple image.

Coffee beans are the seeds inside bright red berries (called coffee cherries) that grow on tropical trees, typically reaching peak quality when cultivated at higher altitudes between 1,000 and 2,500 metres. There are around 60 coffee-producing countries, with the best beans often coming from high-altitude, frost-free regions with steady rainfall and mild temperatures.

What Is a Coffee Bean?

A coffee bean is the seed of the coffee cherry, a fruit that grows on the Coffea plant. Each cherry usually contains two oval seeds that face each other, creating a flat side (the 'flat bean'). Occasionally, a cherry produces just one round seed, known as a 'peaberry' or 'round bean,' which has no significant taste difference. The coffee plant, part of the Rubiaceae family, can grow over 8 metres tall in the wild but is pruned to around 2 metres in farms to improve bean quality and ease harvesting.

How Coffee Beans Are Grown and Processed

Coffee trees thrive in regions with an average annual rainfall of 1,500–2,000 mm and temperatures around 20°C, ideally at elevations of 300–2,500 metres—especially above 1,500 metres, where cooler air slows growth and develops more complex flavors. The coffee cherry matures from green to yellow-green and finally to bright red. Inside each cherry are two seeds (or sometimes one peaberry), surrounded by pulp. These seeds are what we roast and brew as coffee.

After harvest, beans undergo processing to remove the fruit. The two main methods are:

• Washed (wet) process: The beans are soaked, pulped, and fermented to remove the outer fruit layers, then washed and dried. This method, used for about 70% of production in countries like Colombia and Guatemala, results in cleaner, more uniform beans with less risk of spoilage.
• Natural (dry) process: The cherries are dried in the sun with the beans inside, then hulled. This method tends to produce beans with more fruity and fermented flavors but is less consistent.

Coffee Bean Specifications and Grading

Coffee beans are graded and categorized based on several key criteria that affect their market value and brewing potential. Here’s how they’re assessed:

1. Processing Method

• Washed (wet): More uniform, higher-quality beans due to careful removal of fruit and mucilage.
• Natural (dry): Beans dried with fruit intact; flavor can vary more, quality less consistent.

2. Bean Shape: Flat vs. Peaberry

• Flat beans : The standard, two-seed form with a flat side where the seeds touch.
• Peaberry : A rare, single round seed per cherry. No major taste difference but sometimes sorted separately.

3. Bean Size

Measured using screen mesh sizes, common classifications include:

• Flat beans:
  • 20–19 mesh: Extra-large
  • 18: Large
  • 17: Medium-large
  • 16: Standard
  • 15: Medium
  • 14: Small
  • 13–12: Extra-small
• Peaberry:
  • 13–12: Large
  • 11: Medium-large
  • 10: Standard
  • 9: Medium
  • 8: Small

4. Altitude

Beans are graded by the elevation where they’re grown, with higher altitudes generally producing better quality:

5. Defects and Quality

Quality is determined by counting defects (like insect damage, black beans, or broken seeds) in a sample. Fewer defects mean higher grade and better cup quality.

6. Flavor

Different countries employ their own taste tests. Beans are often labeled based on harvest age:

• New crop: Bright greenish beans with vibrant acidity and fresh aroma.
• Past crop:
• Lighter yellow-green, milder and slightly more acidic than new crop.
• Old crop: Yellowish, drier beans with faded flavor, often used in blends or instant coffee.