Have you ever put an unroasted coffee bean in your mouth and tried to bite through it? It is super hard and personally I have not yet been able to complete this task. I also don’t have comprehensive dentist insurance so it’s not at the top of my list.
If you’ve never seen, smelled and tasted a green bean send me an email and i’ll add some to your next coffee order from us.
Anyway, while the beans are getting roasted they are undergoing an endothermic reaction meaning they are absorbing heat and the water inside the bean begins to turn into steam. The pressure builds and builds up until first crack and the bean has its first exothermic reaction and releases much of its built up energy in forms of steam and carbon dioxide. So much so that you can literally hear it crack open and sounds similar to pop corn.
When you hear this sound (or see the slight resulting data on you graph) these beans have just double in size, almost halved in density and by this stage lost roughly 99% of its water content. To me, this is a kind of crazy concept and is also a very exciting moment in every roast.
