A system and method for roasting coffee beans, or similar products, is disclosed. In an aspect the invention includes an acoustic sensor, such as a microphone, which senses the acoustic emissions or “cracks” made by the coffee beans during the roasting process. The acoustic emissions are translated in the system and method to signals that are processed, including in some aspects using frequency domain processing, so as to control the roasting process and achieve a desired final product. The acoustic emissions can also be used to determine if the coffee beans are caffeinated or decaffeinated.