At GSC we roast on a 5kg Diedrich drum roaster. The green coffee beans are fed into a heated cast iron drum and using convection and conduction heat, slowly roast the coffee beans until they reach first crack.
How long they roast after this point varies roast to roast depending on the flavours that we would like to extract from the specific variety/ origin of bean. If you think about roasting food on a cast iron skillet, that's similar to how we roast coffee.
We know how important fresh coffee is to you, but did you know that coffee needs to rest for around 3 days after roasting to degas? Coffee is at it's very best roughly 3 days after roasting right up until 4-6 weeks after the roast date.