What the words mean, and how to brew

The specs and words you meet when choosing a grinder.

• Burr alignment→How parallel and centered the two burrs sit. Poor alignment means one side grinds finer than the other.
• Burr grinder→A grinder that crushes beans between two burrs instead of chopping them with a blade, giving a far more even grind.
• Conical burrs→A burr set where a cone-shaped inner burr turns inside a ring-shaped outer burr. Common in hand grinders and many home electrics.
• Fines→The very small particles every grinder produces. They extract quickly and can slow drawdown or add bitterness.
• Flat burrs→Two parallel, ring-shaped burrs facing each other, with beans ground as they move outward between them.
• Grind index→BrewMark's 0–100 scale for grind size: 0 is espresso-fine, 40 is filter, 100 is the coarsest setting. It lets a setting be translated between grinder models.
• Grind retention→Ground coffee that stays inside the grinder after grinding and comes out with your next dose.
• Grind size→How fine or coarse the ground coffee is. Finer grounds extract faster, so each brew method needs its own range.
• Grind size distribution→The spread of particle sizes a grinder produces at one setting. No grinder makes particles that are all one size.
• RDT (Ross Droplet Technique)→Adding a drop of water to beans before grinding to reduce static, clumping and mess.
• Single dosing→Weighing and grinding only the beans for one brew, instead of keeping a hopper full.
• Stepless grinder→A grinder whose adjustment turns smoothly with no clicks, so any setting between two marks is possible.
• Zero point→The setting where the burrs just touch. Many grinders count their settings from it.

Brewers, methods and the variables you control.

• AeroPress→A manual brewer, invented by Alan Adler, that uses air pressure to push water through the grounds.
• Bloom→The first small pour in pour-over that wets the grounds and lets trapped CO₂ escape before the main pours.
• Brew ratio→Coffee to water by weight, written 1:X. At 1:16, 15 g of coffee takes 240 g of water.
• Brew temperature→The water temperature you brew with. Hotter water extracts faster; light roasts often need hotter water than dark roasts.
• Chemex→An hourglass-shaped glass pour-over brewer that uses thick bonded paper filters for a clean, light-bodied cup.
• Cold brew→Coffee steeped in cold or room-temperature water for many hours, using a very coarse grind.
• Dialing in→Adjusting grind, dose, ratio and time until a coffee tastes right on your setup. Grind is usually the first thing to change.
• Dose→The weight of dry coffee used for one brew, in grams.
• Drip coffee→Any method where water flows through the grounds by gravity, from manual pour-over to automatic machines.
• Filter→Paper, metal or cloth that separates grounds from the brew. Each changes how much body and sediment reaches the cup.
• French press→An immersion brewer where coarse grounds steep, then a mesh plunger pushes them to the bottom.
• Immersion brewing→Any method where the grounds sit fully submerged for the whole brew, such as French press, cupping and cold brew.
• Pour-over→Pouring hot water by hand over grounds in a filter cone, as with the V60, Kalita Wave or Chemex.
• Steeping→Soaking grounds in water without pouring through them. Extraction happens by diffusion.
• V60→Hario's cone pour-over brewer, named for its 60-degree angle, with one large hole and spiral ribs.

Why a cup tastes sour, bitter or just right.

• Acidity→The bright, tart quality in coffee, like citrus or berries. Wanted in many light roasts, and different from sourness.
• Body→How heavy or thin coffee feels in the mouth.
• Channeling→When water finds an easy path through the coffee bed, so some grounds over-extract and others barely extract.
• Cupping→The standard way to taste and compare coffees: grounds steep in a bowl, then the crust is broken and the coffee is slurped from a spoon.
• Extraction→Dissolving flavor from the grounds into water. Too little tastes sour and thin; too much tastes bitter and harsh.
• Over-extraction→Pulling too much from the grounds, usually from too fine a grind or too long a brew. Tastes bitter or drying. Grind coarser.
• Under-extraction→Pulling too little from the grounds, usually from too coarse a grind or too short a brew. Tastes sour or thin. Grind finer.

Shots, drinks and the terms around them.

• Affogato→A shot of espresso poured over a scoop of vanilla gelato or ice cream.
• Crema→The golden foam on top of an espresso shot, formed as CO₂ escapes under pressure. More crema does not mean a better shot.
• Espresso→A small, concentrated coffee made by forcing hot water through finely ground, tamped coffee under high pressure.
• Flat white→An espresso drink with a thin layer of velvety microfoam, smaller and stronger-tasting than a latte.
• Latte→Espresso with a larger amount of steamed milk and a thin layer of foam.
• Microfoam→Steamed milk with bubbles so small it looks glossy, used for flat whites, lattes and latte art.
• Ristretto→A shorter espresso shot: the same dose, stopped with less liquid in the cup.
• Tamping→Pressing the grounds level and firm in the portafilter basket so water meets even resistance.
• Yield→The weight of espresso in the cup, compared with the dose of dry coffee that went in.

From cherry to roasted bean.

• Arabica→The coffee species behind almost all specialty coffee, prized for sweetness and complexity.
• Coffee cherry→The fruit of the coffee plant. Its seeds, usually two per cherry, become coffee beans.
• Dark roast→Coffee roasted into or past second crack, with oily beans and roast-led flavors like chocolate and smoke.
• Decaf→Coffee with most of its caffeine removed before roasting, by water, CO₂ or solvent processes.
• First crack→The popping sound partway through a roast as moisture inside the bean turns to steam. Light roasts end soon after it.
• Green coffee→Unroasted coffee seeds, as they are traded and shipped before roasting.
• Honey process→Drying beans with some of the sticky fruit layer still on, which tends to add sweetness. No honey is involved.
• Light roast→Coffee roasted to shortly after first crack, keeping more of the origin flavors, such as fruit and florals.
• Medium roast→Coffee roasted between first and second crack, balancing origin character with roast sweetness.
• Microlot→A small, separately kept batch from one farm or plot, often with its own processing or variety.
• Natural process→Drying the whole cherry before removing the fruit, which often gives fruity, winey flavors.
• Origin→Where a coffee was grown: the country, region or farm.
• Roast date→The day the coffee was roasted. Most coffee tastes best within a few weeks of it.
• Robusta→A hardier coffee species with more caffeine and bitterness than arabica, common in instant coffee and some espresso blends.
• Second crack→A second round of crackling late in a roast, as the bean structure breaks down further. It marks dark-roast territory.
• Single origin→Coffee from one country, region or farm, rather than a blend.
• Specialty coffee→High-quality coffee judged on a formal quality assessment. For years that meant 80 or more points on the SCA cupping scale.
• Variety (varietal)→The cultivar of the coffee plant, such as Typica, Bourbon, Geisha or SL-28.
• Washed process→Removing the fruit soon after picking and washing the beans before drying, which tends to give clean, bright cups.