Ah coffee. That amazing, delicious, aromatic beverage. It clears the mind and refreshes the soul. I recently spent some time with Sarah Walker, head roaster of Vent Coffee Roasters and learned a bit about her business, and the process of coffee roasting. Walker’s first roasting apparatus was a bread maker and heat gun contraption which she still proudly uses to roast samples. But a bulk of her work is done on a gleaming Diedrich IR-5 roaster.
Tuesday afternoons are roasting time and I stopped by the first floor of The Munsey building, a space Walker cohabitates with Argosy Cafe, to learn a bit about the process. Coffee beans are the roasted seed of the coffee cherry. The pitted cherry is itself used in a tea, called cascara. Coffee roasting is a precise process of timing and temperature and is often different for different beans. The roasting process begins by weighing out beans.
While her roaster can accept 12 lbs of beans, Walker doesn’t fill it completely full. A lot like a washing machine, if filled to capacity, the IR-5 may not produce the desired results. Coffee beans are poured in to a funnel at the top of the Diedrich IR-5, fall through the hopper, and in to the roaster.
Internal arms continuously move the beans to keep the heat even. Keeping the gas/air mix is critical for proper temperature, and Walker keeps simultaneous eyes on the gas manometer and adjusts air flow with a lever on the side of the IR-5.
Walker periodically uses a small scoop, called the keeper, to visually inspect the beans as they are roasting. During roasting the beans change from green to yellow to brown and release delicious scents of caramel and hay.
The heat causes the beans to expand and eventually burst through the outer layer, an event called “first crack“. It sounds a bit like popcorn. Soon after comes “the drop”, where the roasted beans are dropped in to a cooling bin.
Arms slowly stir the beans to ensure they cool evenly.
Bits of chaff and other debris are removed by hand.
Lastly, beans are bagged.
The coffee is served at Argosy Cafe and distributed to restaurants.