Eli Wolcott is all abuzz about socially responsible coffee. The 20-year-old is teaming up with coffee workers in the remote hills of southern Mexico to improve their quality of life and decrease the environmental damage caused by coffee production. Coffee-processing plants use large amounts of water that are then returned to streams, laden with nutrients that lead to fish kills. And tons of coffee fruit, once separated from the bean, are left to rot. Wolcott is working to find ways to reduce the amount of water used, make use of the discarded fruit waste, and give coffee workers a bigger share of profits. Oyster mushrooms may play a key role. Meanwhile, in partnership with Conservation International, the corporate behemoth that is Starbucks this week began selling a limited edition organic coffee grown in shaded coffee plantations, which retain some native trees that provide habitat for migratory songbirds.