Roasting of the coffee beans is what transforms it from a mostly inedible pebble like bean into the delicious cup that we now know and love. The roasting actually transforms the chemical properties of green coffee beans to transform them, the roasting process is what produces the characteristic flavour, causing the beans to both change color and expand. This is where the taste and smell also comes to the coffee beans. Needless to say, the best green bean in the world if roasted improperly won’t produce an edible cup of coffee.
The beans starting out as ‘green beans’ contain all of the same acids, caffeine and ingredients as the roasted beans, but it’s not until the chemical reaction cause by the roasting takes place that causes the taste to be applied to the bean. Green beans are stable and have a long shelf life, unlike roasted beans, so if you’re going to roast your own beans (Kudos!) you can keep your green beans for a long time. This is why coffee beans coming from other countries like Thailand and Indonesia are often shipped as green beans and then roasted closer to where they are consumed.
I hope this sheds the light a bit more on where roasting happens and how if affects the taste. Look for more articles on how to roast your own coffee beans coming soon!