Roast One, Complete
This past weekend marked the successful completion of our first official roast! As expected, a couple of mistakes were made, but that’s part of the fun in learning a new trade. In this post, I’ll cover the process from green bean procurement to the final roasted coffee output, minus tasting notes. Angel and I will be sampling all this week in order to rate the overall roast and consider how to adjust for next time.
Going Green
In order to roast, you first need green coffee. In our previous post, I mentioned getting beans from Sweet Maria’s, a distributor based in Oakland, CA. Being a well-known coffee procurer, Sweet Maria’s offers a lot of options when it comes to green coffee. For our first coffee, I selected 5lbs of Nano Challa Cooperative from the town of Agaro in Ethiopia. One of the primary reasons I selected this bean was that it worked well for both espresso and regular drip coffee. When learning to roast, it’s best to stick with the same bean in order to see how changes in the roast impact the final flavor profile. Having the ability to explore different processing methods made the thought of drinking the same coffee for months on end more tolerable.
Coffee Roasting + Technology
Now, for most people, green beans and a roaster would be enough to get the job done, but what’s the fun in roasting if you can’t collect data and measure changes? One of the coolest features of the Hottop roaster is the ability to link a laptop directly to the machine and control it using software. In the above video, I do a very quick introduction of the Artisan software — a free, open source program to profile roasts — and how it can be used to control various aspects of the roaster including the power, fan, and heat.
Once the roasting begins, Artisan automatically tracks various stages of the process, noting temperature and time on a graph as each step completes. When the roast is finished, you can choose to add additional notes, cupping scores and other small details that are then saved into the roast file. The application itself can be a little clunky at times, but the developer has done a great job of balancing customization with generic roast tracking and specific machine control. The final graph you end up with is a culmination of all the factors from the roast and really makes it easy to identify where you can make tweaks to your process.
Ready for Prime Time
Much like any other coffee process, measuring is step one in roasting. The Hottop roaster has a 225 gram capacity, but I went with 200 grams just to make sure I didn’t fill up the drum completely. Besides measuring weight, it’s also important to capture volume in order to have a rough idea of bean density. As you can see from the photo above, these Nano Challa beans are really small compared to what you may find in your local grocery. Density influences how you approach roasting the bean as you need to make sure it’s completely cooked through without scorching the outside (think cooking meat — you want a nice outside sear, but the inside has to be cooked too). For our target roast of medium (city), I wanted to ensure that I slowly brought the beans to temperature to avoid burning the outer layers.
After recording all the measurements, it’s time to roast. Using Artisan, I charge the roaster up to 395F degrees and add the green beans into the drum. The above clip shows the visible beans rolling throughout the drum. As the temperature rises, the beans go from a pale green color to a darker yellow before browning.
After several minutes (and a bunch of mistakes), “first crack” begins inside the drum which lets me know that the coffee is in light-roast territory. On a more technical note, first crack essentially means that the moisture from the bean has evaporated and an exothermic reaction has taken place. It’s during this time that flavors really begin to develop within the bean. At this point, every second inside the roaster impacts the flavor profile. I prefer medium (city to full city) roast, so it’s only a couple minutes after first crack before dropping the beans from the drum.
Once the coffee is released, it falls into a tray below the roaster where a metal stirrer agitates the beans in order to help speed up the cooling process. At this point, the roast is complete and after cooling, the coffee runs through a small filter to get rid of the extra chaff before being transferred into a storage container.
The Final Bounty
From what you can see in the above picture, I managed to successfully roast our first batch of coffee without completely burning it to a crisp. However, I did make a few mistakes that ultimately influenced how the bean will taste.
In the above graph (produced by Artisan), I point out the places where mistakes were made and how those ultimately carried through to the final roast output. In short, the major mistake made was not applying heat to the roaster at the “turning point” — where the bean temperature (BT) equalizes with the roaster temperature (ET). Normally, you’d see a rapid growth in temperature lines, but as you can see, our temperatures rose a lot slower due to the lack of applied heat for a couple minutes. Fortunately, I didn’t try to compensate too much for the mistake and instead focused on saving what I could of the beans.
And there you have it, our first roast is in the books. Looking back at the experience, it’s hard to believe how quick the entire process takes place. From heating the roaster to ultimately dropping the beans, you’re looking at no more than 12–14 minutes; roasting requires your full attention to be done correctly. In the next blog, I’ll cover cupping the freshly roasted coffee, tasting it throughout the week and what we plan to change for the next roast.
