Types of coffee beans, explained

The short answer

There are two main types of coffee beans, arabica and robusta, which Wikipedia puts at about 60 and 40 percent of the world's coffee. Two minor types, liberica and excelsa, make up the rest. Inside arabica there are many varieties, such as Bourbon, Typica and Gesha, and those are the names you see on a specialty bag.

So "type" can mean two things. The species tells you the broad style: arabica is sweeter and more acidic, robusta is stronger, more bitter and higher in caffeine. The variety, along with where and how the coffee was grown and processed, tells you what a specific arabica will taste like.

The four species compared

Figures from Wikipedia's articles on the coffee bean, Coffea arabica and Coffea liberica. Wikipedia notes that recent genetic work suggests liberica may be several species, with excelsa one of them.

Arabica: the specialty bean

Arabica grows wild in the forests of southern Ethiopia, South Sudan and Yemen. Wikipedia describes it as a natural cross between two other species, robusta and Coffea eugenioides, with four sets of chromosomes where most coffee species have two. It is usually grown between 1,200 and 1,500 m, though farms run from sea level up to 2,800 m.

Its weakness is disease. Coffee leaf rust, a fungus, costs arabica growers up to $2 billion a year, Wikipedia says. That is why breeders keep working on new varieties.

Almost every Massachusetts roaster we list sells arabica, and three say outright that they roast only arabica: Red Barn in Upton, Armeno in Northborough and Mike Shea's in Bridgewater, as their own pages stated on September 27, 2026. See arabica in our glossary.

Robusta: stronger and hardier

Robusta, Coffea canephora, likes it warmer than arabica, at 24 to 30 °C. It carries roughly twice the caffeine or more, and its cup is heavier and more bitter. Its green beans hold about twice the chlorogenic acids of arabica, 140 mg per gram against 65, and less fat: 9.8 to 10.7 g per 100 g of dried beans, against 13.5 to 17.4 g for arabica.

Specialty roasters use it sparingly, mostly in espresso blends. In Massachusetts, Dean's Beans in Orange puts some robusta in its Italian Espresso Roast, a dark blend of Central American coffees. See robusta in our glossary.

Varieties: the names on a specialty bag

World Coffee Research, which publishes a catalog of coffee varieties, sums up the family tree this way: most coffees historically descend from Typica and Bourbon; from the mid twentieth century breeders added rust-resistant varieties crossed with other species; and more recently they introduced F1 hybrids for genetic diversity. The catalog also covers the Ethiopian landraces, the wild and farm-grown types from arabica's home.

These are the varieties you are most likely to see on a Massachusetts roaster's bag, with examples from their own pages on September 27, 2026:

• Pink Bourbon, a Bourbon form with pink fruit, turns up in several Colombian lots on Massachusetts shelves. Broadsheet sells Colombia Wilder Lazo Pink Bourbon, Gracenote a Huila Pink Bourbon community lot, and Aero El Mirador Pink Bourbon. Atomic, Jaho and Armeno list one too.
• Gesha, also spelled Geisha, which appears in World Coffee Research's family tree. George Howell has sold Gesha Village Estate lots from Ethiopia, and Barrington lists Las Brisas Gesha.
• Pacamara. George Howell has sold El Injerto Red Pacamara from Guatemala.
• Peaberry is not a variety but a bean shape: one round seed in the cherry instead of two flat ones. George Howell has sold a Kenyan Mamuto Peaberry, and Mike Shea's and Armeno both list a Tanzania Peaberry.

Does the type change the caffeine in your cup?

Yes, more than roast does. By Wikipedia's figures, arabica beans hold 0.8 to 1.4 percent caffeine and robusta 1.7 to 4.0 percent, so a robusta-heavy blend carries twice the caffeine of an all-arabica coffee or more. Roast level barely moves caffeine by comparison; our light roast page explains why a scoop of light roast has slightly more than a scoop of dark. Wikipedia also notes that higher caffeine is found in plants grown at higher altitudes.

If you want less caffeine without going fully decaf, a half caf blend is the other route. Speedwell in Plymouth sells one called Half Speed, and Three Fins in West Dennis sells Shaka Half-Caf.

Reading type on a bag

Most specialty bags do not say "arabica" at all, because it is assumed. What they show is the country and region, sometimes the farm, the variety, the process (washed, natural or honey) and the roast level. The species only appears when it is unusual, as with robusta in an espresso blend. If you want to taste how much variety and place change a coffee, try the same roast level from two single origins side by side, one Colombian and one Ethiopian.

A roaster in your own state is the easiest person to ask about any of this, because you can visit or write to them. Buying from them keeps that know-how, and the jobs behind it, in Massachusetts. Why local roasters matter.

If you want to work through the varieties without buying a dozen bags, our single origin subscription sends one farm or region per bag from a different Massachusetts roaster each box.

Sources

• Wikipedia, Coffee bean: species shares, caffeine ranges, growing temperatures, lipids and chlorogenic acids.
• Wikipedia, Coffee: how arabica and robusta differ in the cup.
• Wikipedia, Coffea arabica: native range, altitude, hybrid origin, chromosomes, leaf rust.
• Wikipedia, Coffea liberica: share, flavor, kapeng barako, excelsa.
• World Coffee Research, Arabica Coffee Varieties catalog: variety groups.
• Roaster coffees: our roaster profiles, written from each roaster's public pages and checked September 27, 2026.