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RK Drums
How-To Guide

Cacao Roaster Machine — Roast Cocoa Beans by Bean Temperature


Cacao does not crack, and that changes everything

If you have roasted coffee, you already know the rhythm. You listen. First crack arrives and tells you where you are. Second crack arrives and tells you when to stop. Your ears do most of the work, and the thermometer just confirms what you already heard.

Cacao gives you none of that. Some batches pop a little, some barely make a sound, and neither tells you where you are — there is no first crack, no second crack, no moment where the beans reliably announce themselves. Whatever noise you get is not a landmark you can steer by.

That missing landmark is the single reason cacao roasting has a reputation for being hard. It is not that cacao is fussier than coffee. It is that every landmark you would normally navigate by has been taken away. Roast cacao without knowing the bean temperature and you are not roasting — you are guessing, and you only find out whether you guessed right days later, once the chocolate is finished.

So you roast it by temperature instead

Take away the sound and one instrument is left: the temperature of the beans themselves, tracked over time. That relationship — bean temperature versus minutes — is what a roast profile actually is. It is the thing you dial in, the thing you write down, and the thing you repeat.

Note that it is bean temperature, not air temperature. This trips up nearly everyone coming from an oven. Your oven's dial tells you what the air is doing. It tells you nothing reliable about what the beans are doing, and there is no conversion between the two — the gap between air and bean shifts with your batch size, your ambient temperature, how long you have been preheating and how wet the beans are. You cannot calculate your way to bean temperature. You have to measure it.

This is why so much cacao roasting advice reads like a workaround. Bake at 300°F for 20 minutes, stir occasionally, smell for the change. It is honest advice for someone with no way to see inside the roast — but it is a recipe, not a profile, and it will produce a different result in your kitchen than it did in the kitchen it came from.

What an RK Drum with RoastPilot gives you

An RK Drum is a rotisserie drum roaster that installs into the BBQ grill you already own. Solid 304 stainless, all TIG-welded, no rivets, no electronics inside the drum to fail. Cacao drums are built with shorter internal vanes than coffee drums, because a bigger bean needs more clearance to toss freely, and full-length vanes do not leave it enough. The RoastPilot controller puts a thermocouple in the rotisserie handle, in the beans, and sends what it reads to your phone.

  • Live bean temperature — the actual number, throughout the roast, not an inference from the grill's air temperature.
  • Grill temperature alongside it — so you can see how much heat you are applying and what it is doing to the beans.
  • Automatic gas pressure control — you set a target and the controller works the gas to hold it, instead of you crouching at the valve.
  • Saved profiles — when a roast is right, you keep the curve and run it again. That is the whole difference between a good batch and a repeatable one.
  • Session history, graphs and PDF export, with cloud sync and Artisan Scope integration if you want to take the data further.

None of this is exotic. It is what commercial roasting machines have always done, and it is the reason their operators can hit the same cup twice. RoastPilot is $315 and it goes on a drum that lives in a grill.

See the cacao roasters → — drums and kits from 2 to 12 lb, with sizing guidance for chocolate makers.

We have built cacao roasters before

This is not a new direction for us so much as one we have never talked about properly.

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. That last detail is the whole point of this page, and we were building it into cacao roasters a decade before RoastPilot made it standard equipment. The build is written up here.

Chocolate makers have been quietly using RK Drums for a lot longer than that. Walt Lewis of Chiammaya Custom Crafted Chocolate has been roasting on his RK drum since 2004. We simply never built the pages to say so.

The cacao roasting guides

Start here

Roasting method

When it goes wrong

Nibs

Coffee, cacao, and everything else

The same drum roasts coffee, peanuts, nuts and grain. Plenty of RK customers came for one and stayed for the others — a roaster that reads bean temperature is a roaster for anything you want to apply controlled heat to. If you already own an RK Drum, adding cacao costs you a controller and an afternoon.

Common questions

Does cacao have a first crack like coffee?

No. Not in any usable sense. Some cacao pops faintly and some is near silent, but it is inconsistent between batches and origins, so there is no audible landmark you can steer by. Coffee's first and second crack happen because steam pressure fractures the bean structure at a fairly predictable point; cacao does not behave that way. This is why roasting cacao by time and sound does not work, and why a bean-temperature reading is not a nice-to-have but the only instrument you have.

Can I roast cacao in an RK Drum?

Yes. An RK Drum is a rotisserie drum roaster, which is the machine type generally recommended for cacao, and with the RoastPilot controller it reads bean temperature directly — the capability cacao roasting depends on. Batch sizes run from 2 lb to 12 lb. If you are roasting cacao commercially or want a drum built to a specific cacao spec, contact us before ordering so we can talk through the build.

Why can't I just use my oven's temperature setting?

Because the oven dial reports air temperature, and there is no fixed relationship between air temperature and bean temperature. The gap between them changes with batch size, ambient conditions, preheat time and bean moisture. A recipe that worked in someone else's oven will land somewhere different in yours, and you will not know where.

What does the RoastPilot controller cost?

$315 for the complete kit — the WiFi rotisserie handle with its built-in thermocouple, the gas pressure controller with hose and regulator, the drill template and install guide. It works with iPhone and Android and carries a one-year warranty. It is also bundled into the Everything Kits at every drum size.

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.