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How-To Guide

Where Roasting Fits in Bean-to-Bar Chocolate Making

The chain, end to end

If you are new to this, it helps to see the whole path before worrying about any one step. Six stages take green cacao to a finished bar.

  1. Sourcing — buying fermented, dried cacao by origin.
  2. Roasting — developing flavour and loosening the husk.
  3. Cracking — breaking the roasted beans into nib and shell.
  4. Winnowing — separating the light husk from the heavier nib.
  5. Refining and conching — grinding nib to a smooth liquor with sugar, usually in a melanger, over many hours.
  6. Tempering and moulding — setting the cocoa butter into a stable crystal form so the bar snaps and shines.

RK Drums covers step two, and step two is the one that decides how good everything after it can possibly be. But we would rather you knew the shape of the whole thing than bought a roaster under the impression it was the whole kit.

Why we care about step two

The cacao literature is consistent on this point, and we will let it speak rather than pose as chocolate experts: the roast is the stage where flavour is developed rather than merely handled, and roast faults are not recoverable further down the line. Under-roasted cacao is widely described as tasting raw and sharply acidic; pushed too far, the origin character you paid for is reported to disappear into generic roast. Chocolate Alchemy's bean-to-bar guide covers the flavour side properly.

What we can speak to with authority is the machine problem underneath it. Cacao offers no audible cue — no first crack, nothing — so bean temperature over time is the only instrument available to whoever is standing at the roaster. Building a machine that measures that accurately, holds a target, and repeats a curve is squarely our trade. That is laid out in full in why bean temperature is everything.

Roasting also does a mechanical job

Beyond flavour, the roast dries and embrittles the husk so it separates cleanly at cracking and winnowing. Under-roast and the shell clings, so you either lose nib with the husk or leave husk in your nib — and husk in the melanger is grit in the bar. An even roast, with the beans kept moving rather than sitting in a pile, pays for itself twice: once in the cup and once in your winnowing yield.

What you need at each step

StepEquipmentDo we make it?
SourcingA good bean supplier, by originNo — buy from a specialist cacao importer
RoastingDrum roaster with bean-temperature controlYes — this is what we build
CoolingForced-air coolerYes — Model R and Model F
CrackingCracker or modified juicerNo
WinnowingWinnowerNo
Refining and conchingMelangerNo
Tempering and mouldingTempering equipment, mouldsNo

We are not going to pretend otherwise. For the downstream steps you will be buying from specialist chocolate-making suppliers, and Chocolate Alchemy carries most of it — beans by origin, crackers, Sylph and Flux winnowers, Spectra melangers, moulds — along with the guides that explain how to use them. What we make is the roaster, and the cooler that protects the roast you just did.

Coming from coffee?

A fair number of people arrive here already owning an RK Drum for coffee. The good news is that the equipment carries over completely — same drum, same grill, same controller. What does not carry over is the technique.

  • You lose your ears. No first crack, no second crack. Everything you navigated coffee by is gone, and bean temperature has to take its place.
  • Different destination. Cacao finishes far cooler than coffee. Coffee profiles are no guide.
  • Gentler handling. Cacao is more fragile than coffee — pay attention to charge level so the batch cushions itself rather than being worked by the vanes.
  • The husk matters. With coffee, chaff is a nuisance. With cacao, how cleanly the husk releases determines your winnowing yield.

Start at the calibration roast and treat yourself as a beginner for three or four batches. The drum you already know how to run; the beans are a new language.

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Common questions

What equipment do I need to make chocolate from cacao beans?

Six stages: sourcing fermented dried beans, roasting, cracking, winnowing, refining and conching in a melanger, then tempering and moulding. RK Drums makes the roaster and the cooler; crackers, winnowers, melangers and tempering equipment come from specialist chocolate-making suppliers.

Why does roasting matter so much in bean-to-bar chocolate?

The cacao literature is consistent that roasting is the stage where flavour is developed rather than merely handled, and that roast faults cannot be recovered downstream — cracking, winnowing, refining and tempering are mechanical steps that preserve what the roast produced. Under-roasted cacao is generally described as raw and acidic, over-roasted as having lost its origin character. For the flavour side in depth, see Chocolate Alchemy's bean-to-bar guide; our expertise is the machine that lets you control the roast.

Can I use my coffee roaster for cacao?

The equipment carries over — the same RK Drum, grill and controller work for both. The technique does not. Cacao has no first or second crack, so you cannot roast by ear; it finishes at a much lower bean temperature than coffee; it is more fragile, so charge level matters; and how cleanly the husk releases affects your winnowing yield. Run a few calibration roasts before trusting your coffee instincts.

Does roasting affect winnowing?

Yes, directly. The roast dries and embrittles the husk so it separates cleanly from the nib. Under-roast and the shell clings, so you either lose nib along with the husk or carry husk through into the melanger, where it becomes grit in the finished bar.

Keep reading

We build roasters, not chocolate

Worth saying plainly, because it shapes what you should and should not ask us.

We are a machine shop. We have spent twenty years building drums that apply controlled heat to beans and let you see exactly what that heat is doing — for coffee, cacao, peanuts, nuts and grain. Ask us about drums, grills, burners, motors, thermocouples, profiles, batch sizes, or why your roast is running away from you at minute nine, and you have our full attention.

We are not chocolate makers. Fermentation, origin selection, winnowing technique, refining, conching, tempering, recipes — that is a craft in its own right and not ours.

For that side, Chocolate Alchemy is the best resource on the internet and has been since 2004. John Nanci's complete bean-to-bar guide, his 300-plus Ask the Alchemist archive and the Chocolate Alchemy forum will take you further than we could. We send people there happily and often — and if you want to learn profile drum roasting hands-on, they run an all-day drum roasting seminar that is worth the trip.

Get your chocolate craft from him. Get your roaster from us.

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