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Ryan Lenz teaches the history and science of coffee.

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A Cup of Optimism

Ryan Lenz Teaches the Science of Roasting Coffee at Home

If coffee is “optimism in a cup,” as author Michael Pollan writes, then Ryan Lenz’s course on home coffee roasting is a lesson in optimism. The former chemistry teacher has set up an introductory class in Bend to not only demystify the roasting process but to explain how the experience of coffee, from where it’s procured to how it’s roasted and drank, can be highly personal while also connected to the larger world. “The experience of roasting gives you connections to countries you may never have been to,” explains Lenz. “You may not have traveled to Guatemala, but by roasting, it creates a relationship with those local farmers and supports them more directly when you buy (Fair Trade beans) from them,” he says. Lenz was introduced to the larger world of coffee while teaching science at international schools throughout Indonesia, Beijing, and Bangkok. On one particular outing with his 9th-grade students, he found himself in a coffee-growing region outside Jakarta where the group picked coffee berries and he saw rudimentary roasting in local villages. While the best beans would be exported, he watched the cast-off fermented beans roasted on steel sheets over open flames and they tasted unlike anything he had tasted before. His science brain was piqued, and he started to experiment on his own. Today, his personal roasting equipment has traveled across the Pacific Ocean twice. He teaches small-group classes in Bend to get locals hooked on the “science” behind roasting. An opening lesson includes a brief history of coffee, before moving into the chemistry of the process and an understanding of the language and terminology used. The roast color spectrum goes from “First Crack” at 412°F, through “City” to “Full City+,” then “French” to “Burnt“ at higher temperatures of 455°+. For many people, they come to the class to learn about something they already have very strong connections with, says Ryan, but the terminology is brand new.  Ever the teacher, Ryan optimistically shares his knowledge to show that it’s easy and fun to roast coffee at home, explaining, “It isn’t rocket science.” @BlackMagicCoffee, Airbnb Experiences in Bend.

What to Taste

In a Cup of Freshly-Roasted Coffee

A “bloom” is created when hot water strikes ground coffee, creating tiny bubbles of liberated CO2 being released from very fresh, roasted beans.

The subtleties of coffee taste are even more pronounced when beans are freshly roasted, with the best flavors available within the first 48 hours. One of the key notes detected in fresh coffee is a buttery taste, but just as with wines, there is a wide range of tastes as shown on the flavor wheel.


Get Started

Ryan is quick to diffuse common misconceptions about roasting coffee. First, no expensive equipment is necessary. Successful roasting can happen simply, over a gas grill, in a modified popcorn popper, as well as in higher-tech (and higher-priced) roasters. Next, it doesn’t take a long time to roast beans, he explains. In fact, start-to-finish, roasting a batch takes sometimes only 10 minutes—depending on your beans, and desired outcome. While expert roasters must adhere to temperature and timing standards to create consistency in their coffee products, especially if the beans will be sold at a retailer, Ryan encourages home roasters to experiment and embrace variation. “It’s easier than you think,” he says.


  • Ryan Lenz teaches the history and science of coffee.