Two bags land in your galley from the same Colombian farm, same altitude, same varietal. One tastes of clean red apple; the other of strawberry jam and rum. Nothing changed in the field. Everything changed in the twenty-four hours after the cherry was picked, and again in the twelve minutes it spent in the roaster.
Processing: What Happens to the Cherry
Coffee is the seed of a fruit. Processing is how the fruit is removed, and it shapes the cup as strongly as origin.
| Method | Process | Cup character | Risk |
|---|---|---|---|
| Washed (wet) | Pulped, fermented, washed, dried | Clean, bright, transparent acidity | Water-intensive |
| Natural (dry) | Whole cherry dried on beds | Heavy body, berry, fermented sweetness | Uneven, can taste boozy or mouldy |
| Honey / pulped natural | Pulped, some mucilage left on to dry | Between the two; syrupy, soft acidity | Needs careful drying |
| Anaerobic / experimental | Sealed fermentation | Intense, funky, wine-like | Polarising for guests |
Washed coffees are the safe, elegant default for guests. Naturals are exciting and divisive; some guests read fruit as "off". Know which you are serving before you pour it for a charter principal.
What Roasting Actually Does
Green coffee is grassy and inert. Roasting drives moisture off, then triggers chemistry:
- Maillard reactions and caramelisation build sweetness, colour and body.
- First crack (~196-205 C bean temperature) is an audible pop as steam ruptures the bean. Coffee is drinkable from here.
- Second crack (~224-230 C) is the cell structure breaking down and oils migrating to the surface. Roast character now dominates origin character.
- Carbon dioxide is generated and trapped in the bean. It escapes over days, which is why fresh coffee needs to degas.
Roast Levels
| Roast | Colour / surface | Acidity | Body | Best for |
|---|---|---|---|---|
| Light | Pale, dry | High | Lighter | Filter, pour-over, single origin |
| Medium | Chestnut, dry | Balanced | Medium | All-rounder; most house espresso |
| Medium-dark | Dark brown, faint sheen | Lower | Fuller | Espresso with milk |
| Dark | Near-black, oily | Low | Heavy, bitter, smoky | Traditional Italian espresso |
Darker is not stronger in caffeine; roasting burns off a small amount, and dark roasts simply taste more bitter and roasty. Light roasts are denser, harder to dissolve, and need finer grinding and hotter water to extract properly.
Reading a Roaster's Bag
Look for: roast date (not best before), origin and producer, processing method, varietal, altitude, and an intended brew method. A bag with only a best-before date is telling you it was not roasted recently or the roaster does not want you to know.
Onboard Notes
- Very dark, oily beans shed oil into the grinder and hopper and go rancid fast in a warm galley. They also clog the grinder chute. Medium to medium-dark is the practical yacht choice for an espresso machine in daily service.
- Naturals and anaerobics can throw guests. If a guest says the coffee tastes "fermented" or "like wine", they are describing the process correctly, not complaining about a fault. Offer the washed alternative.
- Never buy a coffee for a charter you have not tasted and dialled in first.