Terra_Nera_coffee_beans

Green coffee beans are simply raw coffee beans in their pre-roasted state, the kind that arrive in bulk at coffee houses in large brown jute bags. In this naked state, the beans contain a higher amount of the chemical chlorogenic acid, thought to have a variety of health benefits such as a reduction in blood pressure, the regulation of blood sugar, and increased metabolism. The beans are also a rich source of antioxidants, so while the high temperature inside a roaster will destroy some of those health benefits, boiling them will not as the boiling temperature is about a hundred degrees lower. The flavor of brewed green coffee is light and grassy, making it an attractive drink to enjoy over ice, in the summer.

One method of preparing green coffee:
Bring the raw beans to a boil in water.
1/6 ratio beans to water.
Allow to gently simmer for about 15 minutes or so.
Strain and chill…the longer the beans steep, the higher the caffeine content (although the longer it brews the more bitter it will taste).
The brewed green coffee will last for a few days in the refrigerator.

http://www.webmd.com/vitamins-supplements/ingredientmono-1264-green%20coffee.aspx?activeingredientid=1264&

http://www.sciencedirect.com/science/article/pii/S0091305711002024

Lee and Zhu, 2006
W.J. Lee, B.T. Zhu
Inhibition of DNA methylation by caffeic acid and chlorogenic acid, two common catechol-containing coffee polyphenols
Carcinogenesis, 27 (2006), pp. 269–277