In the Footsteps of Giants: Roasting Coffee Beans Like a Pro

Roasting Coffee Beans

Roasting Coffee Beans

Wanna make like a coffee roaster and learn the steps? You got it. We’ve put together a quick beginner’s guide to roasting coffee beans for your armchair adventure.

Though specifics will vary greatly, the typical coffee house follows a few basic steps. It all starts with a bunch of raw green coffee beans. The roasting process will alter their chemical and physical properties, giving them the taste, smell, and density we all have grown to know and love. Sure, you can still get the acid and caffeine of coffee from the green bean itself, but its taste would be virtually nothing like the coffee any of us are used to drinking.

Ready for a little chemistry tutorial? Here goes. Back in the day, aka 1912, a guy by the name of Louis-Camille Maillard showed the world that using heat to cause a chemical reaction between an amino acid and a reducing sugar resulted in nonenzymatic browning. Translation: hundreds of different flavors can come out of thin air when you heat something in a specific way. That’s called the Maillard effect (brownie points for those who figure out why!), and it’s one of the most important reasons to heat the coffee beans in the first place.

Naturally, with all things chemical, the temperature and time you use matters a lot. Typically, roasters set the roaster for somewhere between 464–527 degrees F, and stick the beans in for anywhere between three minutes to half an hour. In many cases, once the beans hit 347, the roaster then fiddles with the temperature again. That’s because (alert, more chemistry coming), once the beans hit that temp they goes from being a mass that absorbs heat (endodermic) to one that emits heat (exothermic).

Pro roasters go for certain times and temps based on the style of roast they want. The rule of thumb is that the hotter it gets, the darker it gets, the less acidity it retains, and the more of the beans natural oils come out. As for length, pros use a variety of ways to figure out when their beans are done, from checking out the color to listening for the beans to crack. The first crack happens early on, around 401–405, signaling that a light roast is ready. The second crack, which happens at 435–441, separates medium from dark roast.

So that’s the nuts and bolts of roasting coffee beans. Sounds simple enough, right? That might be the case if you didn’t need such fancy equipment. To properly roast coffee beans, you need a pretty fancy roaster. The two most common types are drum roasters, which rotate to keep the beans tumbling around in heat, and hot-air roasters, which blast hot air into the roasting chamber to propel the beans and keep them circulating.

For those of us not ready to go out and become roast-masters ourselves, just remember that fresh is always best. Buy from your local roaster as much as possible, because the fresher ground, the better!