Coffee, Espresso & Brewing Equipment Glossary
Coffee, Espresso & Brewing Equipment Glossary
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The glossary covers coffee origin and processing, roasting, espresso recipes and machines, grinders and burrs, filter brewing, water chemistry, milk, maintenance, commercial café equipment, and troubleshooting.
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Key Coffee & Espresso Definitions
Specialty coffee
Coffee evaluated for high quality, distinctive flavor, careful production, and low defect levels. The term is commonly used for coffees scoring 80 points or higher under established specialty evaluation systems.
Single-origin coffee
Coffee identified with one geographic source, such as a country, region, farm, cooperative, or individual lot, rather than a blend of multiple origins.
Arabica
Coffea arabica, a coffee species prized for broad flavor diversity and widely used in specialty coffee. It generally grows best at higher elevations and is more disease-sensitive than canephora.
Robusta
A common name for Coffea canephora, a coffee species often associated with higher caffeine, strong body, bitterness, and greater heat and disease tolerance than arabica.
Washed process
A process in which most fruit is removed before drying, typically through pulping, fermentation or mechanical demucilaging, washing, and parchment drying.
Natural process
A process in which intact coffee cherries are dried before the dried fruit layers are mechanically removed.
Coffee roasting
The controlled application of heat to green coffee to create the chemical and physical changes that produce roasted-coffee aroma, flavor, color, brittleness, and solubility.
First crack
An audible stage of roasting when internal pressure causes beans to expand and fracture, producing popping sounds and marking a major structural transition.
Extraction
The transfer of soluble and suspended coffee compounds from grounds into water during brewing.
Extraction yield
The percentage of the dry coffee dose that ends up dissolved in the brewed beverage, commonly estimated from beverage mass and TDS.
Total dissolved solids
An estimate of the concentration of dissolved material in a beverage, usually reported as a percentage for brewed coffee or espresso.
Brew ratio
The relationship between coffee dose and water or beverage yield. The exact convention should be stated because filter brewing often compares coffee to brew water while espresso often compares dose to beverage mass.
Espresso
A concentrated coffee beverage produced by forcing hot water through a compact bed of finely ground coffee under pressure. Modern recipes vary widely in dose, ratio, pressure, flow, and time.
E61 grouphead
A classic heavy chrome-plated brass group design introduced by Faema in 1961, known for a thermosiphon-heated group, mechanical brew lever, and pre-infusion chamber.
Heat exchanger
An espresso-machine system in which brew water passes through a tube or chamber heated by a larger steam boiler, allowing brewing and steaming at the same time.
Dual boiler
An espresso machine with separate boilers for brew water and steam, allowing independent temperature control and simultaneous brewing and steaming.
PID controller
A proportional-integral-derivative control system used to regulate temperature more precisely than a simple on/off thermostat or pressurestat in many espresso machines.
Portafilter
The removable handled filter holder that locks into an espresso-machine grouphead and holds the filter basket.
Pre-infusion
The initial wetting of an espresso puck at reduced pressure or flow before full extraction pressure, intended to improve saturation and manage puck resistance.
Flow profiling
Deliberately changing water flow rate during espresso extraction, with puck pressure responding to the relationship between flow and puck resistance.
WDT
Weiss Distribution Technique: stirring or raking espresso grounds with thin needles to break clumps and improve distribution before tamping.
Channeling
Preferential water flow through lower-resistance paths in a coffee bed or espresso puck, causing uneven extraction.
Single-dose grinder
A grinder designed to grind one pre-weighed dose at a time rather than storing a large quantity of beans in a hopper.
Flat burr
A burr set using two generally flat, ring-shaped cutting discs facing each other. Flat-burr grinders can be designed for many different particle distributions and flavor styles.
Conical burr
A burr set using an inner cone-shaped burr and an outer ring burr. Conical designs are common in hand grinders and many electric grinders.
Burr alignment
The condition in which opposing burr faces are positioned so the intended grinding surfaces are parallel and concentric enough for consistent operation.
Retention
Coffee that remains inside a grinder after grinding rather than exiting with the intended dose.
RDT
Ross Droplet Technique: adding a very small amount of water to whole beans before grinding to reduce static and grounds spray.
Water hardness
The concentration of multivalent minerals in water, primarily calcium and magnesium. Hardness affects flavor, extraction, and scale formation.
Limescale
Hard mineral deposits, primarily calcium carbonate, that form when mineral-rich water is heated or concentrated.
Glossary Topics & Related Terms
Coffee Basics & Origin: Coffee, Specialty coffee, Commodity coffee, Third-wave coffee, Green coffee, Roasted coffee, Single-origin coffee, Coffee blend, Espresso blend, Omni roast, Filter roast, Espresso roast.
Processing & Fermentation: Coffee processing, Washed process, Natural process, Honey process, Wet-hulled process, Semi-washed coffee, Anaerobic fermentation, Aerobic fermentation, Carbonic maceration, Controlled fermentation, Extended fermentation, Yeast inoculation.
Coffee Roasting: Coffee roasting, Coffee roaster, Drum roaster, Fluid-bed roaster, Sample roaster, Direct-fired roaster, Indirect-fired roaster, Conduction, Convection, Radiation, Charge temperature, Turning point.
Sensory & Cupping: Aroma, Fragrance, Acidity, Sweetness, Bitterness, Body, Mouthfeel, Clarity, Complexity, Balance, Aftertaste, Astringency.
Brewing Science: Extraction, Extraction yield, Strength, Total dissolved solids, Refractometer, Brew ratio, Dose, Yield, Brew water, Contact time, Flow rate, Agitation.
Espresso & Shot Recipes: Espresso, Espresso shot, Single espresso, Double espresso, Ristretto, Normale, Lungo, Caffè crema, Turbo shot, Sprover, Blooming espresso, Shot time.
Espresso Machines & Components: Espresso machine, Home espresso machine, Prosumer espresso machine, Commercial espresso machine, Semi-automatic espresso machine, Volumetric espresso machine, Manual espresso machine, Lever espresso machine, Spring lever, Direct lever, Superautomatic espresso machine, Grouphead.
Pressure, Flow & Profiling: Pre-infusion, Pre-brew, Soft infusion, Line-pressure pre-infusion, Mechanical pre-infusion, Pressure profiling, Flow profiling, Flow control, Needle valve, Pressure ramp, Declining-pressure profile, Shot profile.
Espresso Puck Preparation: Coffee puck, Puck preparation, Distribution, WDT, WDT tool, Blind shaker, Dosing cup, Dosing funnel, Tamping, Tamper, Calibrated tamper, Self-leveling tamper.
Grinders, Burrs & Grinding: Coffee grinder, Espresso grinder, Brew grinder, Commercial grinder, Single-dose grinder, Hopper grinder, On-demand grinder, Doser grinder, Timed dosing, Grind-by-weight, Bulk grinder, Hand grinder.
Filter & Manual Brewing: Pour-over, Drip coffee, Batch brewer, Immersion brewing, Percolation brewing, Hybrid brewer, V60, Flat-bottom brewer, Cone brewer, Chemex, Kalita Wave, Origami dripper.
Water Chemistry & Treatment: Water hardness, General hardness, Carbonate hardness, Alkalinity, Bicarbonate, Calcium, Magnesium, Sodium, Chloride, Sulfate, Silica, Water TDS.
Milk, Steam & Espresso Drinks: Milk steaming, Milk texturing, Microfoam, Macrofoam, Aeration, Stretching milk, Rolling milk, Milk pitcher, Latte-art pitcher, Cappuccino, Latte, Flat white.
Cleaning & Maintenance: Backflushing, Water backflush, Detergent backflush, Espresso machine detergent, Grinder cleaner, Burr cleaning, Steam-wand cleaning, Milk-system cleaner, Milk stone, Preventive maintenance, Group-gasket replacement, Shower-screen replacement.
Commercial Equipment & Utilities: One-group espresso machine, Two-group espresso machine, Three-group espresso machine, Compact commercial espresso machine, Raised group, Shot counter, Barista lights, Pitcher rinser, Hot-water tower, Coffee urn, Satellite brewer, Portion-control grinder.
Troubleshooting & Coffee Community: Fast shot, Slow shot, Spraying bottomless portafilter, Sour espresso, Bitter espresso, Thin espresso, Weak coffee, Wet puck, Soupy puck, Puck sticking to shower screen, Low brew pressure, High brew pressure.
