Home Coffee Brewing Glossary: Terms Explained Simply

Coffee brewing has its own vocabulary, and a lot of it gets thrown around without explanation. Here are the terms you're most likely to run into, explained in plain English — no barista certification required.

Bloom

The first small pour of hot water over coffee grounds in pour-over brewing, done before the main pour. It lets trapped CO2 (released as beans age) escape, which helps the rest of the water extract evenly. You'll usually see it as a 30-second pause with the grounds puffing up slightly.

Blade grinder

A grinder that chops beans with a spinning blade, like a mini blender. It produces an inconsistent mix of fine dust and large chunks in the same batch, which is why it's generally not recommended — see our grinder guide for why this matters.

Burr grinder

A grinder that crushes beans between two abrasive surfaces (burrs) set a fixed distance apart, producing a consistent particle size. This consistency is what makes it possible to "dial in" a grind at all. See our budget gear guide for specific picks.

Chaff

The thin, papery skin that flakes off coffee beans during roasting. You'll sometimes see small bits of it in your grinder or French press — it's harmless and normal, just a byproduct of the beans themselves.

Crema

The thin layer of reddish-brown foam that sits on top of a shot of espresso. It's specific to espresso brewing (from pressurized extraction) and doesn't apply to drip, pour-over, or French press coffee — if your home-brewed cup doesn't have it, that's completely normal.

Dial in / Dialing in

The process of adjusting your grind size (and sometimes ratio) step by step until your coffee tastes balanced rather than bitter or sour. See our full guide on how to actually do this.

Drip coffee

Coffee made by an automatic machine that heats water and drips it over grounds in a basket filter — the classic countertop coffee maker. It's a percolation method, similar in principle to pour-over but automated.

Extraction

The process of water dissolving flavor compounds out of ground coffee. Under-extraction (water moves through too fast, or grind is too coarse) tastes sour or weak; over-extraction (water sits too long, or grind is too fine) tastes bitter or harsh. Getting extraction right is what "dialing in" is really about.

French press

An immersion brewing method: coarse grounds steep directly in hot water for several minutes, then a metal mesh plunger separates the grounds from the liquid. Forgiving, full-bodied, and no paper filters required. See our pour-over vs. French press comparison.

Grind size

How fine or coarse coffee grounds are, usually described on a spectrum from coarse (like sea salt) to fine (like table salt or flour). Different brew methods need different grind sizes because they keep water in contact with the grounds for different lengths of time.

Immersion brewing

Any method where grounds sit fully submerged in water for the whole brew (French press, cold brew), as opposed to percolation methods where water passes through and drains away (pour-over, drip).

Percolation

A brewing method where water passes through coffee grounds and drains away, rather than sitting immersed with them. Pour-over and drip coffee are both percolation methods.

Pour-over

A manual brewing method where hot water is poured over grounds sitting in a filter cone, dripping through into a cup or carafe below. Slower and more hands-on than a drip machine, with more control over the result. See our starter guide for the basics.

Ratio (coffee-to-water ratio)

The proportion of coffee to water used in a brew, usually written like 1:16 — meaning 1 gram of coffee for every 16 grams of water. It's the single most useful number for consistent coffee, and a kitchen scale makes it easy to hit reliably.

Roast date

The date coffee beans were roasted, as opposed to a "best by" date (which is often just a long shelf-life estimate). Coffee tastes best within a few weeks of its roast date — always prefer a bag that lists one.

Single-origin

Coffee sourced from one specific country, region, or farm, rather than mixed with beans from elsewhere. It's often prized for having a distinct, traceable flavor profile, as opposed to a blend designed for consistency.

TDS (Total Dissolved Solids)

A measurement of how much coffee is actually dissolved in your brewed cup, expressed as a percentage. It's how coffee professionals quantify "strength" objectively — most home brewers never need to measure it, but you'll see the term in more technical brewing discussions.

Third-wave coffee

A movement that treats coffee as an artisanal product worth the same attention as wine or craft beer — emphasizing single-origin sourcing, light roasting, and precise brewing. It's the philosophy behind most specialty coffee shops and roasters today.

Water temperature

The temperature of the water used for brewing, ideally 195–205°F (90–96°C) — just off a full boil. Water that's too hot can scorch grounds and taste bitter; water that's too cool under-extracts and tastes flat.