Home Roasting & Green Coffee Guide
Roasting your own coffee gives you control over freshness and flavor — and green (unroasted) beans cost a fraction of roasted retail. This guide explains how to read a green coffee listing, choose a lot, and get started roasting at home.
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What is green coffee?
Green coffee is the raw, unroasted seed of the coffee cherry. It is shelf-stable for months to a couple of years when stored cool and dry, which is why roasters and home enthusiasts buy it in larger sacks and roast in small batches as needed.
On Who’s Brew, green coffee is its own product type, sold by weight (e.g. 1 lb sample bags up to 50 lb GrainPro sacks) directly from importers and roasters.
How to read a green coffee listing
- Origin & region: where the coffee was grown — the single biggest driver of flavor.
- Varietal: the coffee plant variety (e.g. Bourbon, Caturra, Gesha), which influences cup character.
- Process: washed, natural, or honey — how the fruit was removed, which shapes acidity and fruitiness.
- Crop year: the harvest year. Fresher crop generally roasts more predictably; past-crop can still be excellent but behaves differently.
- Screen size: bean size, graded on a screen scale (e.g. 15–18). More uniform size roasts more evenly.
- Moisture %: green moisture content (ideally ~10–12%). Affects how the bean takes heat.
- Density / altitude: higher-grown, denser beans usually need more energy and reward a slower roast.
How much should you buy?
Beans lose roughly 12–18% of their weight during roasting (water and chaff), so 1 lb of green yields a bit over 0.8 lb roasted. For a first try, a 1–5 lb bag lets you dial in a roast without committing to a sack.
Once you settle on a lot you love, larger sacks (and bulk/volume pricing where the vendor offers it) bring the per-pound cost down significantly.
Getting started roasting at home
- Air roasters & popcorn-style poppers: cheapest entry point, great for 60–120 g batches.
- Drum & hybrid home roasters: more even roasts and larger batches, with profiles you can repeat.
- A scale, a timer, and somewhere to vent smoke are the only other essentials to start.
- Rest roasted beans 2–5 days before brewing so CO₂ can off-gas.
Frequently Asked Questions
Is home-roasted coffee cheaper than buying roasted?
Usually yes. Green coffee costs far less per pound than roasted retail, and buying larger sacks (or bulk tiers) lowers the price further. The trade-off is your time and a small equipment investment.
How long does green coffee last?
Stored cool, dry, and out of direct sun, green coffee keeps well for many months and often a year or more — far longer than roasted coffee, which is best within a few weeks of roasting.
What roaster do I need to start?
You can start with an air popper or an entry-level home air roaster for small batches. Drum roasters give more control and bigger batches when you’re ready to scale up.