Interview With a Coffee Roaster

Alex Roberts, 38, is the master roaster at Roast Coffee, an unusual startup. This Emeryville, California company pairs coffee expert Roberts with the Bacchus Management Group, a San Francisco Bay area restaurant group that's brewing up a new twist in dining--sourcing and roasting its own beans to ensure first rate coffees for its customers.

How do you describe the smell of roasting coffee?
It depends on the level of roast. In the beginning of the roasting process you get this moist, grassy smell. Then it gets more hay-like. And then it starts to get caramelized and get into chocolaty aromas and peanut-popcorn smells. If you continue to roast darker, you get into more of the smoky, bittersweet chocolate aromas.

Do you roast with a timer, or just by your nose?
I like to use everything I can get my hands on to give me information about what's going on. I use a thermocouple in the bean mass itself, which gives me a bean temperature. That's basically a thermometer in the beans that gives me a temperature on a digital display. And I have an air probe. So I kind of judge the difference between the two, like how hot the coffee is in comparison to the ambient temperature of the air in the rotating drum. I think small batches of coffee seem to taste better. They're easier to control. There's more air flowing through the coffee. A small batch is from five pounds to 125 pounds. We do 24 pound batches.

We don't do any pre-blending. If I have an espresso blend with Brazil, Sumatra, and maybe an Ethiopian coffee, we roast each coffee separately. We don't mix them together and put them in the roaster. You can really bring out the best qualities of each coffee, instead of doing a generic roast for all the coffee.

What lies behind the title master coffee roaster?
It's pretty much self-proclaimed. But there is a roasters' guild, which I'm a part of, that is working on a criteria to determine if we could actually give people a certified master roaster title. Here at Roast Coffee, that title simply means that I'm in charge of sourcing the coffee, sampling the coffee, determining the best roast profile for it, roasting it, getting it out, and doing it consistently.

What happens to green coffee beans during roasting?
First you're drying out the coffee, and then you start to bring it up quickly at higher temperatures to caramelize the sugars and start a process called pyrolysis. It's where the sugar and the moisture split from the coffee bean and it makes a cracking sound. It's basically the water in the bean boiling and cracking the bean.

We're heating with hot air and with direct heat on the bean from the skin of a conductive heat drum. Others roast with a fluid bed roaster, which is like a hot air popcorn popper and heats the coffee without any direct, bean to metal contact. That kind of roasting takes five to six minutes. We do the slower, drum roasting style, which takes more like 12 to 16 minutes per batch. I like to take most of my coffees right at the second crack. The bean is now twice the size of when you put it in and weighs about half as much. After the second crack you get into those really dark roasts, like a lot of companies do, but we kind of stay out of.

Is a freshly roasted coffee bean as good as it gets? That is, does the quality of the brewed coffee fall off day-by-day, perhaps even hour-by-hour, after roasting?
If you take it right out of the roaster, it's got CO2 coming out of the coffee, so if you try to brew it, it won't let the water in as easily, because it's pushing so much gas out. Coffee tastes best probably a day after it's been roasted. The quality will start to fall off after a week to two weeks. It starts to get oxidized. You lose some of the aroma. It gets a little bit flat. If you go over three weeks, the oils that come out of the surface of the bean will start to get a little stale and rancid tasting.

Does vacuum packing help preserve roasted beans?
It helps. But I tell people to think of coffee like fresh bread. You can take a fresh baguette and wrap it in cellophane and it will still be soft, but it's not going to taste the same as a fresh loaf of bread. You lose some of that sparkle.

Which raises the option of roasting at home. Online, you can find countertop coffee roasters for as little as $179. How much of a coffee fanatic does one need to be roast beans at home?
It's doable. I think it can be fun and you can get better coffee than a lot of what's out there, because it's going to be fresh and you're doing small amounts that you're going to use quickly. The cheaper home roasters don't bring out the depth of flavor as the drum roasters, but I think you can do a pretty good job and learn a lot about coffee. But you've got to be into it, because you're going to spend 45 minutes to do three to five days worth of coffee. I think it's a great hobby, like beer brewing.

Roast Coffee sources and roasts beans for The Village Pub, Spruce, and the Pizza Antica restaurants. Will we see more of this at other fine restaurants—the same attention paid to coffee as to organic vegetables, grass fed beef and sustainable seafood?
I think it's a definite trend. If you drink coffee, it's the last thing on your palate when you leave the restaurant. Grinding it fresh and brewing it fresh for each serving makes all the difference.

At Spruce, the coffee menu includes these offerings: La Minta, Single Estate, Costa Rica—$8; Ethiopian Sidamo—$5; Peaberry Tanzania—$7; and Bolivian Caranavi—$6. Has the day of the coffee sommelier dawned?
I think so. I'd love to have the first job as a coffeelier, let's call it. This would be somebody who understands all the single origins. All the specifications of the farm it came from, all the nuances of the coffee. Is it high grown, low grown? If there's a blend, what each coffee in the blend contributes. The coffeelier would also suggest coffee and dessert pairings.

— Written by John Grossmann

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