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Art of The Home Roast

In Brief:

Blue Bottle Coffee owner James Freeman is a green bean roasting guru, and he started his empire with the simplest of tools: an oven. Here’s how you can make extraordinary, home-roasted coffee with these six steps.

If you need green beans to roast your own at home, try Pena Roja, grown on a family-farm in Guatemala, and with the help of our friends at Sweet Maria’s.


I started crudely.

I read an article somewhere about roasting your own beans and it sounded like a fun, geeky thing to do. So I went to a family-run coffee importer in South San Francisco, bought a few pounds of green beans and fired my chintzy oven up. The oven is a blunt instrument for roasting coffee. It’s not for everybody. But it’s fun for certain people to do things the hard way.


Turn your oven to 500 degrees and now let it really heat up. Leave it for a half hour, forty-five minutes. You want the entire oven soaked with heat, as hot as it can get.


Take the beans and spread them evenly on a baking sheet, preferably a perforated baking sheet. As the beans are roasting, I take the pan and shake it every couple of minutes to agitate the beans. The beans on the outside of the pan have a tendency to cook faster than those on the inside. So, shaking them around makes the roast more even. You can also use a wooden spoon to move them around.


Seven, eight minutes. You’ll hear the first crack. It’s the popcorn reaction: the moisture in the cell wall of the bean starts to boil and bursts through the shell. Now, decisions need to be made. Do you pull the beans out of the oven before the second crack or keep them in? I think it’s more delicious to pull the beans out before the second crack. You’ll taste more of the origin notes.


The difference between the first and the second crack, in essence, is the difference between a light and dark roast. How do you tell when they are done? You get a flash light and look at the color of the coffee–maybe you have a sample in mind. It’s a little like pasta: you have to take pasta off the heat and start draining a little before it reaches its optimal texture. Remember the coffee beans will continue to cook for four or five minutes after you take them out of the oven. If you go past the second crack, you have to monitor it carefully: the third crack is when the fire department comes.


I’d have two pretty big colanders, and I’d go out on the back porch and pour the beans from one colander to another to let the chaff, this papery stuff, waft away into the neighbor’s yard. I’d do that four to five minutes, till the beans cooled down. The chaff can be a mess.


Time is critical. Early on, I wanted to figure out how the coffee tasted different after Day 2, Day 3, Day 4. This was revelatory to me, tasting how the coffee changed and improved throughout the week, but only to a certain point. Generally, the lighter the roast, the longer you’ll want to wait before it’s at its peak: the moment that the confluence of body and brightness and complexity all work best together. Like everything else, it’s a process of discovery.