"It smells sweet, like candy," my friend said as I extended my wrist to his nose. My skin had absorbed the caramel flavors that had been wafting around me all day like a welcome second-hand smoke. It was the smell of coffee roasting.
It was a bad day to hang out near a coffee roaster -- much less two. The high was 96 degrees, with the humidity already maxing out at typical St. Louis swampy levels, when I went to view the roasting operations at both Northwest Coffee Roasting Company and Kaldi's Coffee Roasting Company. But, as Kaldi's lead roaster Andrew Timko told me, "We have to roast even on day like today. People still drink this stuff."
I started my day at Northwest Coffee Roasting Company's Central West End location. As I walked up the gravel path, the loud rumblings of the roaster were already audible. Sunlight spilled through the garage-style pull-up door at the front of the café. There were a few die-hard café- goers who didn't seem to mind the noise and bustle of the roaster. Northwest's owner, Rick Milton, greeted me as I rounded the counter to the roaster, and we started to talk coffee.
Freshly roasted coffee was already turning slowly in the cooling tray below the mouth of the roaster, a 1957-vintage 22-kilo German-made Probat -- a classic Cadillac of coffee roasters. A tiny porthole in the front face of the roaster revealed loose yellow beans turning inside the drum. Between the heat of the roaster and the weather outside, part of me wondered who was roasting whom as we stood next to the Probat.
"Artisanal roasting is analog instead of digital," Milton said. "We roast by sight and sound. Some people are really proud of the computers they use when they roast their coffee, but a computer can only roast according to time and temperature. This means that you can end up with two coffees [artisanal and conventional] that look the same but taste completely different."
Artisanal coffee roasting is more about guidelines than rules. There are certain temperatures you know you need, but the adjustments to time and temperature that steer the coffee to the desired roast require a kind of communion with the roaster.
The trier is the most obvious tool. The trier sits on the face of the roaster like a nose. Roasters pull it out several times throughout the roasting process, like a wine maker draws wine from a barrel to follow the beans' development. Besides the trier, the rest of the process is on the roaster to know when to hit the heat and when to lie off, how long to keep the beans roasting and at what temperature. It's all a bit like riding the tiger (a 400-degree tiger).
Fernando Rebelo, Wikimedia Commons
Green (unroasted) coffee beans
Coffee beans pass through a series of stages in the roasting process as the puckered green beans metamorphosize into the recognizable dark, plump ones. All roasting goes through the drying stage as the coffee is first poured into the roaster. This releases the first bit of water in the beans. Next the roasting moves on to the yellowing stage, where the first sights and smells of caramelization start.
First crack is the name given to the beans when the water vapor and carbon dioxide inside the beans finally bursts, "popping" the coffee like popcorn. When the beans reach first crack, the popping beans echo off the sides of the drum, sounding like a rain stick turned upside down. The coffee at this stage is lighter and larger (and more recognizable) than the green beans at the beginning of the process.
Timko told me that Kaldi's leans towards the first crack philosophy of coffee: "When you're roasting coffee from a special lot, like some of the Costa Rican coffee we recently bought, the lighter roast highlights the coffee's natural flavors better." As the roast continues past first crack it starts to assert itself more in the flavor of the coffee. A look back at my column about cupping reminded me that Kaldi's recent specialty coffees -- Burundi Kinyovu Lot #5, Kenya AA Gethumbwini, etc. -- are all very light roasts.
Northwest follows another style of roasting called "full city roast" that takes the beans to the second crack. While first crack is caused by the expansion of water and carbon dioxide inside the bean, the second crack is the bean's shell starting to fracture under the heat. Milton's full city roast traces its roots along the west coast from one of the original Starbucks roasters in Seattle down to Peet's Coffee in San Francisco.
"The secret to good roasting," Milton told me, "is to stretch the period where the beans' sugars caramelize long enough to develop all the flavors without burning them." That's the goal of the second crack, to maximize the caramelization in the roasting process past the first crack's lighter roasts without crossing the line into burnt beans.
Aaron Logan, Wikimedia Commons
The second wave of popping can sometimes leave a small pockmark on the surface, like a tiny porthole into the bean's darker haul. "Coffee beans roast from the inside out," Milton said as he took a small handful of the roasted Papua New Guinea off the cooling tray. "That's why the coffee looks darker on the inside compared to the outer shell. That little pockmark is the sign of really good coffee." Take a look at the beans the next time you buy a pound from Northwest, especially a darker roast like their Sumatra for these tiny telltale signs of second crack.
(For the more curious [and geekier] reader, Sweet Maria's has a great online guide to coffee roasting, tracing the roasting process step by step from green beans at one end to charcoal at the other.)
There are so many steps in the journey of a coffee bean, from its roots on a farm in Guatemala or Indonesia to the importers and roasters and finally to your cup at home. Java Enabled has already examined coffee from the source's side with farmers in Mexico, Tanzania and Uganda, but the local roaster is a far more accessible source to learn more about coffee. Both Shaw Coffee, Ltd. and Northwest Coffee Roasting Company roast their beans in plain view at their respective cafes on the Hill and in the Central West End. The folks at Kaldi's are also open to the public touring their roaster on St. Bernard (just call ahead). If any readers know of other places that roast out in the open please let us know.
By the end of my day with the roasters my skin had absorbed the sweet smell of kettle corn (or candy to my friend's nose). Check out one of these café-roasters for a first person view of the process and see what you smell like at the end of the day.
Zach Dyer is a writer living in Saint Louis. He did his thesis research on coffee farmers in Southern Mexico. Since then, he has visited coffee plantations in Costa Rica and Mexico as well as roasters and cafés across the U.S. He blogs about coffee for Gut Check every Wednesday.