Tanzania Coffee Industry Value Chain Analysis. Recent macroeconomic literature indicates that coffee is Tanzania‘s largest export crop. It contributed some $112 million to the country‘s export earnings in 2007/2008 and accounts for about 20% of Tanzania‘s foreign exchange earnings. Coffee has been the mainstay of the country‘s agriculture-based economy since its introduction as a cash crop around 100 years ago. Coffee production is concentrated in five main geographic areas of Tanzania, in the north (Kilimanjaro, Arusha and Tarime), in the west (Kigoma and Kagera) and south (Mbeya Iringa and Ruvuma).