Think of the hottest day you’ve ever experienced. (Those of you who have experienced Torontonian heat waves can skip this exercise. You have an unfair advantage.) Now imagine such soaring temperatures while you’re standing next to a 450 degree farenheit steel drum.
Welcome to coffee roasting. On a cold winter day, the heat radiating from the roaster warms fresh-from-the-cold hands and occasionally dries soggy mittens. But as spring gives way to summer, the blistering heat separates the women from the girls and the boys from the men. Why do roasters expose themselves to such extremes? That’s another kind of fire: passion.
On the surface, roasting looks simple: add a little heat and turn the beans brown. Actually, if we didn’t care so much about bringing out the very best in the bean, it would be that easy. After all, coffee farmers were stirring beans in a pan over an open flame long before the first commercial roaster was invented.
However, the reactions going on inside the bean during roasting are so complex that without due care and attention, it’s all too easy to roast away the flavours that make coffee so exciting. If you’ve ever wondered how the rockstars of coffee can liken the flavour of a bean to Granny Smith apples, graham crackers, and Chinese Five Spice (I’m not kidding, I’ve had it), there’s a good reason. The application of heat at the right time supports the formation of hundreds of aromatic compounds – upwards of 850, in fact. Depending on the country of origin, the alititude at which they’re grown, and the processing methods they undergo, each coffee bean contains a unique, inherent blend of aromatics that roasters try to coax, cajole, and beg to the forefront of the cup.
With so many variables to account for – the relative humidity in the roastery, the conditions during shipping, and probably planetary alignment on the day the coffee cherries were picked – it can feel as if more can go wrong in roasting than can go right. Drag out a roast by applying too little heat? Muddled and uninspired. Give it too much gas, too quickly? The coffee equivalent of cooking a frozen turkey; roasted on the outside and raw on the inside. But when we start with a moderate, sustained application of heat to a quality green coffee, the beans will tell us what they need. We’ll tweak it from there. Shaving a minute off the roast cycle or taking it a few degrees darker or lighter can really make a coffee shine. We’ll keep trying. In the pursuit of the best roast, there is ample kindling to keep a roaster stoked.
Roasting is hot, yes, but it’s also fun, frustrating, and challenging. If coffee roasters seem to be a passionate bunch, it’s because their work is never complete. There is no one way to roast coffee, but everyone starts at the same place: apply heat.