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Coffee Roasting Basics

First Crack and Other Stages

Coffee roasting is cool. The looks of approval and interest I get when I answer “What do you do?” are affirming. People like meeting the coffee roaster.

I began roasting five years ago. Some people roast for 50 years and feel like they’ve never mastered the trade, but with 5 under my belt, I think I can give you the basics. Roasters buy coffee, roast coffee, and monitor the quality of their product and the cleanliness of their facility. To try my beans, pick up a bag or two here. Here’s what I know:

man standing posing for a photo
parengo coffee bag and beans

Coffee Buying 101

I imported a roaster one time, and it was a huge hassle. Luckily, exporters, importers, brokers, and agents of all sorts handle most of the crazy work of shipping, duties, tariffs, taxes, and customs. For a coffee roaster, working with an importer makes life easy. Ally Coffee, Cafe Imports, Ninety Plus, Airship, and others like them do a great job of sourcing awesome coffees from around the world and bringing them stateside for roasters like us to choose from. We request samples and pick out what we like best, then negotiate prices. Often, importers offer price breaks at large volumes, storage for a small carry fee, and some other options based on commodity futures on the Coffee C market. When a company gets rolling, coffee buying can be the most fun part of the business. When it’s all said and done, you receive burlap sacks filled with around 150 lbs. of green coffee each – picked, de-fruited, washed, dried, and bagged in their countries of origin, ready for your coffee roasting to begin.

Coffee Roasting 101

Roasting a batch of coffee takes 7-15 minutes, depending on who you are, but a lot happens during that short window. Green coffee is dense and filled with water at the cellular level. That water must be cooked out for the bean to become edible or grindable and brewable. Roasters come in all shapes and sizes. At Parengo, we’ve used a Hottop, a North, and a Proaster. The two styles of roasters are drum and fluid air bed. Drum roasters rotate the beans in a drum that lays on its side like a clothes dryer. Flames below the drum cook the beans, and the drum turns constantly to keep the beans from receiving too much contact heat from the metal and burning. Fluid air bed roasters suspend the beans above a jet of hot air like a magic show. They tend to develop brighter flavors in the coffee, in my opinion. Drum roasters are largely preferred in the industry. Popcorn poppers, sheet pans in the oven, and skillets over a campfire can also be used to roast coffee, so go wild.

three mugs filled with coffee beans, grounds and liquid coffee
person collecting coffee grounds

Conductivity

However you roast your beans, here’s what you’re doing: first you’re adding a lot of heat to the considerable mass of beans. You want the water which is present in the beans and in the humid air of the drum to conduct the heat into the middle of every bean, consistently bringing each cell toward its boiling point at the same time. At the point at which the cellular water boils, you want to decrease the heat so as not to burn the now-dry beans, and you want to increase the exhaust fan to pull air through the drum, thereby pulling moisture, steam, smoke, and dust out of the drum. Later in the roast, the airflow should be high and the heat should be low, ensuring that no smoke damages the beans and that the outside most layers of the beans don’t overcook.

All the Stages

At some point, the beans pop. This is called First Crack. An exothermic reaction, First Crack-adds heat, smoke, and noise to your roast. This is also the point at which a lot of things are happening. Water is by-and-large exiting the drum in the form of steam and smoke. Acids are turning to sugars, caramelization is going on, and the Maillard effect is taking place. All of this begins, ends, or continues around First Crack.

Before First Crack, during the Drying Phase, we pay attention to the moisture level of the beans. Colors will change from green to tan, aromas go from grass to feed to straw to bread, and the beans look visibly dryer every few seconds over the first 5 or 6 minutes of a roast. After First Crack or the Development Phase, most of the flavors we love to get formed as the molecules rearrange due to the absence of water and the addition of heat causing chemical reactions.

Finally, the roasted coffee beans are ejected from the drum and cooled in a cooling tray. The roaster prepares for another batch. The whole place smells like Pop-Tarts.

a pot on a protector
pouring coffee into a mug

Roaster Practices

After the coffee is roasted, roasters spend a lot of time cleaning. The motors on the roaster must be greased, the chaff collector must be emptied, and the bazillion pounds of dust must be wiped down, vacuumed, and/or otherwise disposed of. Oils, fuzz, dust, cleaner residue – none of this should ever make contact with roasted coffee beans, so the conscientious roaster takes great care to keep the machine spotless and dry.

Cupping

Additionally, roasters must “cup” yesterday’s batches. This process involves grinding a small portion of each batch, brewing it straight into the water, letting it steep, and then slurping it up with spoons. Cuppers then spit the coffee into a spittoon (or a paper cup) and do it again with the next batch. Common practice says that the loudest slurper is the most experienced cupper in the room.

coffee mug with latte art and flowers
stack of papers on a deck

Notetaking

Roasters take copious notes during the roasting and cupping processes. We plot time and temperature on graphs so that we can calculate each batch’s rate of rise. If, during cupping, one batch of Ethiopia tastes juicier than another batch of the same origin, we compare our charts to try to figure out what happened during each roast that would cause them to differ. Notes help us figure this out, although many high-tech roasters now use roasting software, such as Cropster Roast, which takes care of all of this charting for us.

Now you know…

In conclusion, a coffee roaster works a fun and fascinating job. He or she also often smells like fire and grease and plants. My time learning to roast made me feel awesome, and in the process, I also learned how to rewire electric heating element connectors, to solder a Chinese circuit board, to nurse a pilot light, to jerry-rig a condensation catcher beneath an exhaust chimney using female products, and to disassemble a cooling fan. I learned a lot about pressure and humidity and the fickleness of smoke. What a job! Good luck in your coffee roasting endeavors.

Once again, here’s a link to the beans we roast in Southeast Missouri. Also, check out some other posts to find out what to do with the coffee once you get it roasted!