Roasting and Blending Coffee Bean

https://www.blackoutcoffee.com/blogs/the-reading-room/the-basics-of-blending-coffee

https://espresso-experts.com/blogs/espresso-machine-experts/coffee-roasts-guide-everything-you-need-to-know

https://legacy.sweetmarias.com/library/blending/

https://www.greenbeanhouse.co.nz/page/classic-blends.html