Coffee Dictionary: Key Terms Every Specialty Coffee Lover Should Know

If you’ve ever wondered what makes a coffee bean ‘specialty,’ why some beans are round while others are oval, or what the difference is between a wash and a natural process, you’re not alone. These aren’t just trivia—they’re the building blocks of understanding how your coffee is grown, processed, roasted, and brewed.

In this coffee dictionary, we break down over 40 essential terms every coffee enthusiast should know, from the type of coffee cherry to the mechanics of espresso extraction, all with exact numbers, temperatures, and processes as originally detailed.

Coffee Bean Basics

The foundation of all coffee starts with the bean—but not all beans are created equal. Here’s what those terms on bags and in cafes really mean:

• Coffee cherry: The fruit of the coffee tree, with a bright red skin that resembles a cherry.
• Peaberry : A rare mutation where one seed in the coffee cherry absorbs most of the nutrients, growing round instead of flat. Only one round bean forms per cherry instead of two oval ones.
• Maragogype : An unusually large coffee bean variety, often with mild flavour despite its size.
• Coffee belt : The region between the Tropic of Cancer and the Tropic of Capricorn, where conditions are ideal for coffee cultivation.

Processing Methods

How coffee cherries are turned into beans greatly affects flavour. These are the main techniques:

• Dry process : Coffee cherries are sun-dried before the beans are separated from the pulp.
• Washed process : Uses water to remove the coffee cherry’s outer layers, resulting in cleaner flavours.
• Honey/pulp natural or semi-washed : A hybrid method using both sun-drying and water to process the beans.

Other important post-harvest terms include:

• Green bean / Raw bean: Unroasted coffee bean.
• Aged bean : Green beans stored properly for years to develop deeper flavours.
• Specialty coffee: Coffee produced with meticulous care at every stage—from farming to roasting—standing apart from commercial-grade coffee. Recognized by organisations like the SCAA (U.S.) and SCAE (Europe).

Bean Varieties & Defects

Not all coffee plants are the same—and neither are their beans:

• Arabica : The most common high-quality coffee species, with 44 chromosomes. More delicate and flavourful but harder to grow.
• Robusta : A hardy, high-yield species with stronger, harsher flavours. Commonly used in instant coffee.
• Silver skin : A thin membrane on the surface of green beans that usually falls off during roasting.
• Defect beans : Beans that are chipped, discoloured, misshapen, or insect-damaged.

Roasting Science

Roasting transforms green beans into the aromatic brown ones we brew. These terms define critical moments in that process:

• First crack : Occurs around 190–200°C, when beans expand and make a cracking sound as internal moisture escapes.
• Second crack : Around 230°C, a softer, more rapid series of cracks indicating further breakdown of the bean structure.
• Degassing : The ongoing release of carbon dioxide after roasting.
• Resting / Aging beans : Allowing roasted beans to degas fully for several days to reach optimal flavour.

Brewing Equipment Glossary

From grinders to espresso machines, here’s what those coffee tools are actually called:

Grinders

• Blade grinder: Not mentioned here, but commonly confused; the article lists:
• Spiral burr grinder : Burr shaped like a propeller.
• Flat burr grinder : Uses flat grinding discs.
• Cone burr grinder : Uses cone-shaped burrs.

Grinding & Dosing

• Hopper : The bean container on top of a grinder.
• Bean container / Dosing chamber : Holds ground coffee; in commercial machines, often doubles as a doser.
• Doser : A tool to measure consistent amounts of ground coffee, often built into the dosing chamber.
• Dose reducer : A small part in some Moka pots to reduce coffee dose.

Espresso Components

• Portafilter : The handle that holds the coffee filter basket and is locked into the espresso machine.
• Filter basket : The basket inside the portafilter that holds the ground coffee; comes in various sizes.
• Group head : The part of the espresso machine where hot water exits to brew espresso.
• Blank filter : A portafilter filter with no holes, used for backflushing the machine.
• Pump : The mechanism that pressurizes water in an espresso machine.
• Tamper : Tool for pressing coffee grounds in the portafilter; metal tampers are preferred.

Moka Pot Parts

• Steam valve : Safety and pressure-regulating valves in a Moka pot; the relief valve opens at a set pressure, the other maintains it.
• Upper chamber : The top part of a Moka pot where brewed coffee collects.
• Lower chamber : The bottom part, where water is heated.

Other Brewing Methods

• French press / Plunger pot: Not named here directly, but related terms:
• Cloth filter : A fabric filter used in pour-over or immersion brewing.
• Metal filter : A very fine metal mesh used to brew coffee without paper.

Espresso-Specific Terms

• Espresso: Coffee brewed under high pressure with a small amount of nearly boiling water.
• Single shot (Single): About 7–9g of coffee, yielding one shot.
• Double shot (Double): About 14–18g of coffee, the standard espresso serving.
• Triple shot (Triple): About 21–27g of coffee for a larger shot.
• Crema: The golden-brown foam on top of a well-pulled espresso shot—it’s a sign of quality.
• Bloom (bloom): In pour-over brewing, the initial wetting of coffee grounds to release gases and improve extraction.

General Coffee Science & Culture

• Cupping : The professional method for evaluating coffee flavour. Ground coffee is steeped in hot water, then tasted with a spoon without filtering.
• Extraction: The process of dissolving soluble compounds from coffee grounds using water.
• Caffeine: A chemical compound (C8H10N4O2) found in coffee; acts as a stimulant.
• Oxidation: A chemical reaction with oxygen that can degrade coffee flavour over time.
• Maillard reaction : A non-burning heat-driven reaction during roasting that develops complex flavours—often incorrectly called ‘caramelization.’
• Atmospheric pressure : The pressure exerted by the Earth’s atmosphere, equal to 1 bar or 1 kg per cm² at sea level.
• Barista: A skilled professional who prepares espresso-based drinks; the term originates from Italian.
• Latte art / Pouring milk: Creating patterns in espresso drinks by pouring steamed milk—commonly known as ‘latte art’ when done skillfully.

Frequently Asked Questions

What is a peaberry coffee bean and why is it different?

A peaberry, or in Chinese, occurs when one coffee seed in a cherry grows larger and round by absorbing most of the nutrients, instead of forming two flat seeds. Only about 5% of coffee cherries produce peaberries, and they often roast differently and sometimes have distinct flavour profiles.

What’s the difference between washed and natural coffee processing?

Washed process removes the coffee cherry’s pulp using water, leading to cleaner and brighter flavours. Natural process dries the whole cherry in the sun before removing the bean, often resulting in sweeter, fruitier, and more complex flavours due to longer contact between bean and fruit.

What are first and second crack in coffee roasting?

First crack occurs around 190–200°C, when moisture escapes the bean and it expands audibly. Second crack happens near 230°C, a softer sound indicating further structural breakdown and development of darker roast characteristics.

What is espresso crema and why is it important?

Crema is the golden, creamy foam on top of a properly extracted espresso shot. It’s formed by emulsified oils and CO2 and is considered a sign of freshness and good technique. Crema enhances both flavour and aroma in espresso.

What does 'specialty coffee' actually mean?

Specialty coffee refers to beans that are cultivated, harvested, and processed with exceptional care to achieve high quality. It is distinct from commercial coffee and is certified by organizations like the SCAA and SCAE. These beans typically score above 80 on the 100-point specialty coffee scale.

What is blooming in pour-over coffee?

Blooming is the initial quick pour of hot water over freshly ground coffee to release trapped CO2 gas. This step, usually done before the full brew, helps improve extraction and flavour clarity in pour-over methods like V60 or Chemex.

Recommended FrontStreet Coffee for Coffee Knowledge

Explore the fundamentals of specialty coffee with FrontStreet’s single origins: try the Ethiopia Humbera for bright floral notes, Yirgacheffe for juicy citrus and berry tones, or the Brazil Queen Manor for nutty chocolate balance. Each highlights how origin, processing, and roast shape your cup. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.