With the most pessimistic reports predicting the near extinction of arabica coffee in the next fifty years due to climate change, the specialty coffee industry has an invested interest in reducing coffee’s environmental impact. But most coffee roasters utilize technology that is more or less a century old, and far from fuel efficient. A conventional drum roaster burns a lot of fossil fuels, not to mention the by-products that are put into the atmosphere. But a new in-shop roaster from Bellwether Coffee aims to change the way the industry roasts coffee. We interviewed Bellwether Coffee’s COO Arno Holschuh to find out how their zero-emissions roaster works, and why he thinks it could disrupt a whole industry. 

Bellwether Coffee is manufacturing the first zero–emissions coffee roaster. I’m sure your technology is proprietary, but can you tell us something about how the roaster works?

I can tell lots of things about how it works! For starters, our roaster uses a fixed-drum roasting architecture. This is also known as the “modified drum” architecture. What I mean is that the roasting drum is made out of stainless steel and does not rotate; the beans are mixed to assure even roasting by “paddles” that lift the beans off the drum surface and loft them into the air. (This design was popularized by Loring.)
We really like this design. It’s easier to control the heat application than in a traditional drum system, because your only heat input into that system is hot air. Air is a great medium for conveying and applying heat, because its temperature is easy to measure. It is also possible, although not really easy, to control the air’s temperature. With traditional drum systems, you have heat conducting in from the metal drum, but that drum temperature is really hard to measure. It’s spinning, for one thing, which kind of means wires won’t work.
So hot air comes in from the back, passes through the coffee beans, and exits through the front of the drum. The post-roast gases go through a chaff cyclone, just like you would expect, and then through an assembly that applies heat and cleans off the particulates and VOCs. This cleaning process is primarily catalytic, but not just catalytic. To get a system like this to work correctly, you have to be pretty clever about how you implement the catalytic element.
After being cleaned and heated, the gases go into a blower that moves them back through the roast chamber.
This process — chamber, cyclone, heater/cleaner, blower — is repeated as the air recirculates through our device. You mentioned we have a ventless, emissions-free roaster. An equally important facet of our roasting technology (an essential, intertwined one) is that our roaster is recirculating. All roasters have the same basic purpose: To take heat energy and put it into coffee beans. Most roasters generate immense amounts of heat, put a tiny fraction of that heat into the coffee, and then dispose of the heat as quickly as they can through an exhaust system. Think about a roaster’s exhaust stack: all that valuable heat being drawn off by the exhaust fan and dumped onto the air. That heat was supposed to end up in coffee. With our roaster, we take that exhaust heat and use it as roasting heat.
Clearly this makes us more efficient. But it is more than that: It makes us thermally stable. When you are generating the kind of massive heat input required by a normal roaster, it is hard to be precise. Even more so because your roaster is losing heat really quickly (and not just through the exhaust system — there’s all that uninsulated metal, too). In our system, we have a stable amount of heat in the system, and we just need to add enough to counteract the small, predictable thermal losses through our insulation, and the heat required for the roasting process itself. It’s like the difference between watering your garden with drip irrigation — or a firehose.

What sort of control do roasters have over their roast profiles?

Roasters have complete control over their profiles! Roasters can draw a profile using our iOS app; that profile is sent to the device, which will follow it very precisely. The big leap here is that the roaster does not control the process of heat creation and application; the roaster controls the outcome of heat creation and application. As a former roaster, I think just following a roast profile precisely is already quite a feat. To do that while also designing the profile to try new things… that’s a lot to ask. Ships have captains and navigators: The captain decides where to go, the navigator gets you there. With our device, the roaster is always the captain!
There are other things to control than just heat application, but we’re not quite there yet. We have unlocked methods for controlling other key variables for coffee quality. But we can’t quite talk about them yet.
But there’s another piece to this: We will provide roast profiles with each green coffee in our marketplace, profiles we have designed in our pilot facility specifically for that coffee. So you do not need to have any idea at all about how to roast in order to start.

One of the interesting applications of this technology is that it allows cafes to roast in-house without an expensive and space-consuming ventilation system. Do you think the Bellwether roaster can help connect consumers to the roasting and sourcing process?

Absolutely. We are trying to make that connection stronger. We demystify roasting by bringing it into the retail space and making it an activity that anyone –not just physically strong people of a certain height able to lift a whole batch into a hopper — can do. As they say, small is beautiful. A 3-kilo batch can be lifted by anyone, and our hopper is removable, so that they can weigh the coffee at hip-height. In fact, we have an integrated scale at that height!
Bringing consumers closer to the farmers gets easier when you’ve brought roasting to the shop, too. We will deliver content about farms that is best-in-class in it’s quantity and quality. Picture, videos and descriptions will be available for our retail partners to use for their own marketing. But in addition, we have an iOS application (separate but connected to our core app) that will allow end consumers to connect directly with the farmers. Our Tip the Farmer app can be displayed next to the point of sale, and will show customers information about the farm that grew the coffee they are holding. even further, customers will be able to communicate directly with the grower, and even send them a tip. A quick note about that tip: In the US, the most common amount to tip at a coffee shop is $1. Not everyone tips, but when they do, it’s usually $1. If one person out of 20 tips, that’s an extra $2/kilo in payment to the farmer. The C market is at $2.70/kilo right now. $2/kilo is a tremendously meaningful amount of cash. We think growers are our partners, and that without them, we are sunk. They aren’t being paid enough to eat well (with obvious, notable exceptions like Brazilian fazenda owners). It’s time to change that.
There is one additional piece here, which is trying to identify and then pay producers their true cost of sustainable production. It quickly gets complicated to discuss how one assesses that price! But we are attempting to do so.

Bellwether also has a curated green coffee marketplace. In a sense, it seems like one-stop-shopping for a café owner. Who are you working with to source your coffees?

We work within the existing green coffee infrastructure. We have zero desire to be an importer — we think the existing players are already operating at a very high level of service to clients in the consuming countries. So we work directly with some farmers, and work with good importers for other coffees. We’re privileged enough to be buying from Royal, Sustainable Harvest, and InterAmerican. We think importers are a valuable part of the value chain.

The Bellwether roaster roasts up to seven pound batches. Are there plans to produce a larger, more commercial machine?

Not yet, although we get asked a lot. We need to focus on this product.
I want to get into something fascinating but kind of hard for a lot of people to wrap their heads around: It might be better to never ever get a big roaster again.
Our roaster is very cheap to operate as a production unit.
The most expensive variable cost in roasting is labor — way more expensive than rent or energy. Because it has an automated product flow, our roaster requires very little labor to operate.
Because it requires no venting, it requires almost no infrastructure spend.
Because we sell coffee in 22-lb boxes, it requires no materiel handling operation (no forklift etc).
So we think that if you have 10 busy cafes, it’s probably cheaper to get 10 Bellwether roasters, one for each cafe, than it is to ever build a roastery in a warehouse and put a big old 40-kilo drum roaster in there. Really!