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How-To Guide

Cocoa Bean Roaster Machines — Cacao Roasters from 2 to 12 lb

A cacao roaster that shows you the bean temperature

Cacao gives you no first crack and no second crack. The roast is silent, which means bean temperature is the only instrument you have — and until recently, nothing at a sensible price gave it to you at a sensible batch size.

An RK Drum is a rotisserie drum roaster that installs into a standard rotisserie gas grill. Solid 304 stainless, 16 gauge, TIG-welded throughout, no rivets, no electronics inside the drum to fail, lifetime warranty on the drum itself. Add the RoastPilot controller and a thermocouple in the rotisserie handle reads the beans directly and sends it to your phone.

If you have been roasting cacao in an oven, or in a countertop coffee roaster you had to drill out to fit a probe, this is the machine you have been improvising toward.

What makes it a cacao roaster

Two things, and neither is marketing.

The vanes are cut shorter. The vanes are the ribs inside the drum that lift the beans and tumble them, and their length is sized to the bean. Coffee beans are small, so coffee vanes are long. Cacao is a bigger bean — and peanuts bigger again — so it needs more clearance to toss than a coffee bean does, and full-length vanes do not leave it enough room. We cut them about an inch shorter for cacao and nuts, which is the traditional spec: the shorter rib lifts and drops the larger product instead of crowding it, so the batch mixes. That is the real mechanism behind every warning you have read about coffee roasters being rough on cacao. We build cacao and nut drums with shortened vanes, specified at build time. We can do that because every RK Drum is built to order in our own shop rather than stamped out to a single pattern.

It reads bean temperature. Cacao has no first or second crack, so there is nothing to roast by ear. The RoastPilot controller puts a thermocouple in the rotisserie handle and reads the beans directly.

Choose Cacao as the primary roasted product when you order and the drum is built with the shorter vanes.

Why RoastPilot is not optional here

On the coffee side we treat the RoastPilot controller as an upgrade, because coffee roasters can navigate by first and second crack and many happily do.

For cacao we would tell you plainly: buy it with the drum. There is no audible cue to fall back on, so without a bean probe you are running the roast blind and every batch teaches you almost nothing. $315 gets you live bean and grill temperature, automatic gas pressure control holding your target, saved profiles you can run again, graphing, session history, PDF export, and Artisan Scope integration if you want to take the data further.

Every Everything Kit below is available with the controller included.

Pick your size

Work backwards from how much finished chocolate you need in a week, and remember that the green weight you charge is well above the nibs you keep once the husk is off. Give yourself headroom. There is more detail in what size cacao roaster do you need?

SizeBest forKit with RoastPilot
2 LBLearning, sample-roasting a new origin 2 LB Everything Kit + RoastPilot
4 LBSerious hobby, gifts, market stalls 4 LB Everything Kit + RoastPilot
6 LBSide hustle, wholesale trials 6 LB Everything Kit + RoastPilot
8 LBSmall commercial production 8 LB Everything Kit + RoastPilot
12 LBMicro-factory volume 12 LB Everything Kit + RoastPilot

Already own a grill and a rotisserie motor? You can buy the drum on its own or the controller on its own.

Built for cacao, not adapted to it

One thing worth knowing before you order. The vanes inside a drum — the ribs that lift the beans and tumble them — are sized to the bean. Coffee beans are small, so coffee vanes are long. Cacao is a bigger bean and needs more clearance to toss than coffee does; full-length vanes do not leave it enough room. That is the real mechanism behind the warnings you will read about coffee roasters damaging cacao.

We cut the vanes about an inch shorter for cacao and nuts. Same drum, same steel, same welds — shorter vanes, more clearance, so the larger product tosses properly. We can do that because every RK Drum is built to order in our own shop rather than stamped out to one pattern. Pick your primary roasted product when you order.

Turndown, and why it matters more than the maximum

Most people shop on the top of the range. For cacao the bottom matters just as much.

The 12 LB drum's recommended working volume runs from about half a pound to fifteen pounds. A batch charged too thin in a big drum has nothing to cushion against — which is how cacao gets damaged in large commercial roasters that cannot be charged below twenty pounds. A wide turndown range lets one drum sample-roast a new origin on Tuesday and run production on Thursday.

Cool it fast

Cacao carries enough heat to keep roasting after it leaves the drum, so slow cooling moves your finish temperature away from the one you carefully hit. At two pounds a box fan and a colander will do. From six pounds up, a Model R or Model F cooler stops being an accessory and becomes part of the roaster.

We have built cacao roasters before

In 2015 we built a custom cacao roaster for Carol Morse of Acalli Chocolate out of a Hobart HR7 — a laterally opening drum door so it could be serviced in place, an external sample port for pulling beans without disturbing the roast, and a temperature probe reading directly from the bean mass. The build is written up here. Walt Lewis of Chiammaya Custom Crafted Chocolate has been roasting on his RK drum since 2004.

If cacao is your main product rather than something you also roast, email us before you order. We have fabricated drums to customer specification for cacao, including sample-port and probe arrangements, and there is a custom drum option if you already know what you need.

Learn the roast

Common questions

Do you sell a dedicated cacao roaster?

Yes — it is the same drum body as our coffee roasters, built differently. Cacao drums get shorter internal vanes, because a bigger bean needs more clearance to toss and full-length vanes do not leave it enough room. Add the RoastPilot controller for real bean-temperature reading, which cacao needs because it has no audible crack. Choose "Cacao" as the primary roasted product when you order and the drum is built accordingly; for commercial cacao operations we also build to customer specification.

How much does a cacao roaster cost?

An Everything Kit with the RoastPilot controller covers the drum, mounting hardware, motor and controller; you supply the rotisserie gas grill. The controller on its own is $315. Compared with commercial cacao roasting equipment, which starts in the thousands and typically cannot be charged below 20 lb, the drum-on-a-grill route is a fraction of the outlay.

Can one drum roast both cacao and coffee?

Yes, and many of our customers do — the grill, motor and controller are all shared. The one build difference is vane length: cacao and nut drums get shorter vanes because those beans are physically larger. A short-vane drum still roasts coffee. The technique differs more than the hardware does: cacao has no first or second crack, finishes at a much lower bean temperature, and is more fragile, so run a few calibration roasts rather than trusting your coffee instincts.

What size cacao roaster should I buy?

Work backwards from finished chocolate per week, allowing for the weight lost to moisture in the roast and to husk at winnowing. Roughly: 2 LB for learning and sample roasts, 4 LB for serious hobby, 6 LB once you are selling, 8 LB for steady small commercial output, 12 LB for micro-factory volume.

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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