One of my motivations to write this blog is that I want to demystify coffee and share insights about the coffee industry that I don’t see talked about a lot. To live up to that ideal let me tell you something awkward about being a coffee roaster. This is something that I’ve discovered by reading the most referenced literature on coffee roasting, speaking to experienced coffee roasters and through my own experience working in several coffee roasteries and starting my own - working it from the ground up. Most of us coffee roasters only have a vague idea of what we are doing. We’re all mainly just guessing. This statement might provoke some people but let me reiterate that I just want to demystify what coffee roasting really is, I'm not trying to offend anyone.

Let me explain. I’m not saying coffee roasters aren’t able to make delicious coffee, and I’m not claiming that we don’t have SOME idea of what will happen when we throw green coffee into a hot roasting machine. In fact, even though coffee roasting is a complicated process, the chemical changes happening in the coffee is well-documented and understood. How these changes relate to flavour in the coffee, though, is based on conjecture, anecdotal evidence, and observation. Our methods for affecting change in coffee flavour during roasting are incredibly simple, and it essentially boils down to changing heat and airflow during the roast at certain stages. Our tools for measuring coffee roasting, like temperature probes, all give us second-hand information, a bit like looking through a microscope via a pair of binoculars.

What this means is that there are a ton of ideas and theories about what happens to coffee flavour during the roasting process. There’s no unified theory that works for everyone and we’re all figuring it out by ourselves through trial and error. Skilled roasters are the ones who’ve mastered their roasting system and have developed routines that give them a reliably desired outcome in the coffee. Even then, though, they only know that their approach to roasting works for them, and they might only have vague ideas WHY it works and it can’t be easily transferred to another roasting system. Having said that, maybe a trained chemist might better understand it, but most of us coffee roasters unfortunately have no background in science.

In episode 19 of the Coffee with April Podcast, four years ago, Patrik Rolf spoke with renowned coffee roasting consultant Rob Hoos. In this episode Patrik said something profound: “coffee roasting is hobby science at best,” which Rob nodded in agreement to. This was an eye-opening statement for me, because at the time I thought I was the only one who felt that way.

When I was just starting out as a roaster, I had this vague sense that there were these industry secrets that all other roasters knew, that I was still trying to figure out. Everyone else outwardly seemed to know what they were doing, and no matter how many books and articles about roasting I consumed, I still couldn’t quite grasp these “secrets.” In the end I had to use trial and error to figure out what worked on my roasting system and develop my own theories to support what I was observing. It wasn’t until I had figured it out for myself and started talking to other roasters that I realized this was how almost all other roasters learned their craft as well. The lucky ones get hired into an existing roastery and receive training by someone with experience on that system, the rest of us have to teach ourselves. There are no secrets that I wasn’t privy to, there are no shortcuts, it really all comes down to throwing some green coffee into a roaster and tasting the results afterwards. Rinse and repeat.

A good example of this is how roasters approach profiling a new coffee. We take copious measurements of everything we can about the physical properties of the coffee: moisture, density, colour, process, bean type and the altitude it was grown at. Then we estimate from our experience how that coffee will behave in the roaster, heat it up, throw the coffee in and cross our fingers that we were correct. The more times we do this, the more data we have and the more accurate our estimations become. Some roasters will also do a test roast on a sample roaster or a 1kg roaster to see how the coffee behaves, but that just gives them a little more data to base the next step on: how the coffee will behave during production roasting on a larger machine. Many times, if we have a profile that’s worked for a similar coffee, that works as a starting point to profile a new coffee. Other times it doesn't work at all. But the first roast of a new coffee is never, ever, the best roast of that coffee. It’s only by roasting, tasting, and making adjustments that we end up with the ideal roast profile. That’s it, that’s literally all we do, and even when we have a profile that works, that still doesn't mean that we know WHY that profile works better than all the previous ones. To me, realizing this was a huge disconnect with the prevalent idea of the artisan roaster unlocking the full potential of a coffee.

When I was a rookie barista working in London, the talented coffee roaster Richard Shannon, then at Workshop Coffee Co, told me that all a coffee roaster does is to turn coffee beans brown. I didn't fully understand what he meant, but now that I’m a coffee roaster myself I couldn't agree more. This might be another potentially provoking statement, but coffee roasters are less important than coffee farmers. If a coffee we’ve roasted ends up tasting great, it’s because the green coffee was great and we didn’t mess up the roast profile. Roasters do not add anything that wasn’t already there. It’s like colouring by numbers and then calling yourself an artist. At least in Norway where I’m based, I don’t see a lot of roasters who claim to have all the answers. Most are quite humble and open about what they do, and how little we actually understand about the roasting process beyond the few parameters we can measure and control.

Since I can’t speak for everyone, I’ll wrap it up by only speaking for myself. I only have a vague idea what I’m doing. I can see what seems to work when I throw green coffee into my roaster, and I’ve developed a routine that allows me to produce coffee that I think is tasty. I can’t say for sure why it works, or if the coffee might even taste better by doing something different, but based on books and articles and my own observations I have theories. The only way I can test these theories is by roasting and tasting, and if the coffee continues to taste the way I want then the theories are valid. Until one day they aren’t, then I’ll have to adjust and make new theories. Or, in other words, trial and error.

- Adrian Berg -