You don’t have to be a roaster to be able to create a perfect latte but knowing a bit about how your coffee is roasted can give you a new understanding of the power of the bean.
It’s easier to monitor quality when you’re producing something in smaller batches and small-scale roasters are becoming more and more common, experimenting away in backyards and café storage rooms.
The roaster controls the transfer of heat to the beans by adjusting airflow, gas levels, drum speed, charge weight and the most important, time. Each tiny adjustment can make a huge difference to the final flavour. Roasters use sight, sound and smell to judge how the coffee is coming along, watching it change colour, listening out for the loud noises and inhaling all that lovely coffee smoke.
There are many ways to describe the roasting process, but it goes roughly along these lines:
Drying: The beans steam, changing from green to brownish yellow and might start smelling a bit grassy or like bread.
Primary Development: Beans start to give off that familiar coffee smell, turn light brown and begin to smoke.
First Crack: Beans make a loud crackling noise, the sign that the bean fibres are splitting and they’ve started to roast.
Secondary development: From here, the beans start to expand and darken as they caramelise. Depending on taste, the roast can be stopped at any time after the first crack reaches its crescendo and most single origin roasts are best stopped between this stage and the first few rustles of the second crack.
Second Crack: The second crack is like a last warning, where timing becomes essential. It’s quitter than the first crack, more like the sound of crinkling paper. As the second crack gets louder and smoke fills the air, the beans become very dark.
STOP! The beans are burnt. Any coffee made from these will taste a bit like rubbery charcoal. Back to the drawing board.