Coffee Bean
Guide

Two species dominate the commercial coffee world: Coffea arabica and Coffea canephora, known universally as Robusta. A third species, Coffea liberica, exists in small quantities but is commercially marginal. For most coffee drinkers, the practical choice is between Arabica and Robusta, or a blend of the two.

Robusta has a complicated reputation in specialty coffee circles. At low quality it is genuinely harsh and unpleasant. But high-quality Indian Robusta, particularly from Coorg and Chikkamagaluru, is a different animal entirely: rich, full-bodied, with an earthy depth that adds complexity to espresso blends. Many of the best Italian espresso blends contain 15 to 20% quality Robusta for precisely this reason. Dismissing Robusta entirely is a specialty coffee affectation that does not survive contact with a well-sourced Indian blend.

For pure manual brewing: Arabica always. For espresso blends targeting body, crema, and caffeine: a quality Arabica-Robusta blend is a legitimate and often excellent choice.

Roasting transforms the green coffee bean through a series of chemical reactions: the Maillard reaction develops sugars and amino acids into complex flavour compounds, caramelisation darkens and sweetens the bean, and cell structure changes as CO₂ builds inside the bean and causes it to expand. How far the roaster takes this process determines the roast level and fundamentally shapes what the coffee can and cannot do in the cup.

The key thing to understand about roast level is that it is not a spectrum from bad to good. It is a spectrum from origin-forward to roast-forward. Light roasts preserve the natural character of the origin: the soil, the altitude, the variety, the processing method. Dark roasts develop the character of the roasting process itself: the Maillard compounds, caramelised sugars, and carbon notes that are consistent regardless of where the bean came from. Neither end is superior. They serve different purposes and different brewing methods.

Processing refers to what happens to the coffee cherry after it is picked and before the green bean inside it is dried and exported. The processing method has a profound effect on flavour profile and is one of the most significant variables that determines how a coffee tastes before it is even roasted. Understanding processing helps you predict flavour and choose beans that suit your preferred brew method.

The country and region of origin shapes a coffee's fundamental flavour character through soil composition, altitude, climate, and the varieties grown there. While processing and roast level modify what origin delivers, the origin itself sets the flavour ceiling. Here are the major producing origins and what to expect from each.

This is the practical heart of the Coffee Bean Guide. Knowing your origin and processing is useful background knowledge. But knowing which roast level to use for which brewing method is what determines whether your next bag of coffee produces great results or disappoints you.

French Press and Moka Pot sit in the middle: both work well with medium roasts that have enough body for immersion or pressure brewing but enough origin character to remain interesting in the cup. A washed Colombian at medium roast is one of the most versatile beans in any brew kit for exactly this reason.

A specialty coffee bag carries a significant amount of information. Knowing how to read it helps you make better purchasing decisions and set accurate expectations before you brew.

Roast date vs best before. Always look for a roast date, not a best before date. Best before dates can be set 12 to 18 months after roasting and tell you nothing useful about freshness. A roast date tells you exactly how old the coffee is. For espresso, coffee is best between 7 and 21 days post-roast. For filter brewing, 5 to 28 days post-roast. After 4 weeks the aromatics degrade noticeably, though the coffee remains drinkable for longer.

Variety. The coffee variety (or cultivar) is a subspecies of Arabica with its own distinct flavour characteristics. Heirloom Ethiopian varieties like Kurume and Dega produce complex, wild florals. Bourbon produces sweetness and red fruit character. Gesha (or Geisha) is the most celebrated variety in the world for its jasmine, bergamot, and tropical fruit complexity. SL28 and SL34 from Kenya produce the classic blackcurrant and tomato acidity Kenya is known for.

Altitude. Higher altitude means slower cherry development, more complex sugars, and more flavour potential. Coffees grown above 1800 metres are typically more complex and expensive. Below 1000 metres, flavour is simpler and body heavier. Altitude is a useful proxy for complexity when tasting notes are vague.

Tasting notes. On specialty bags, tasting notes are descriptors of what the roaster perceives in the cup, not added flavours. A bag that says "blueberry and jasmine" does not have blueberry syrup in it. These compounds occur naturally through the combination of variety, altitude, processing, and roast. Treat tasting notes as a direction, not a guarantee. Your extraction, water quality, and equipment will affect whether those notes are fully expressed in your cup.