Sumatra island has the most complete tropical biodiversity island of Indonesia, also the island of coffee. expanding from Aceh province at the tip of Sumatra and ended at Lampung on Sunda strait, contine to Java, Bali, Celebes at the north, then Lombok, Sumbawa, Flores, Timor and ended at Papua. Some large island with highland and volcano land suits for growing high quality coffee. Arabica and Robusta available at most part of Indonesia.

Starting from Aceh, Gayo highland not really well-known by the world or local, lays a broad highland grows Gayo organic shade grown Arabica  coffee. Gayo coffee export to the world by the name of Sumatra Mandheling. It is true also, since the Mountain Chain (Bukit Barisan) is expanding from Gayo highland Aceh province, to Mandheling North Sumatra highland, west Sumatra Padang, south Sumatra, Bengkulu and ended at Lampung that exist mount Krakatau over the sea on Sunda strait. The Chain Mountain consist of active volcano, some are erupted to form huge highland reservoir we call high elevation lake. i.e. Lake Lut Tawar at Gayo, Lake Toba at Mandheling, Lake Maninjau, Lake Singkarak Lake Atas, Lake Bawah at west Sumatra, Lake Gunung Tujuh Jambi, Lake Ranu at Bengkulu, all are the results of volcano eruption million years ago, also series of active volcano on the Chain mountain. The geologist call the Chain Mountain as a Ring of Fire, I call it Ring of Flavor. Since the coffee from this geographical condition create the best flavor.
 

Well known as world largest organic shade grown Arabica coffee production. Many district produce flavour Arabica and organic shade grown bean.

Mandheling share the Barisan mountain with Gayo with different but alike flavor charater, since there exist  Toba and Lut Tawar at Gayo form huge volcanic eruption. Mandheling have a strong spicy aroma and full body. while Gayo tend to be Herbal also with full body.

The largest Robusta production region of Indonesia at most part of island from medium altitute 300 mup to altitute that suits for for the Arabica. Bengkulu, Lampung, Bukit Tinggi, Palembang all summed to the port of Lampung for export.   

The birh of coffee long before the American countries. broght from India by Dutch Indies. Arabica available at West, Central, and East Java Estate highland.  East Java coffee have lower acidity, nutty and cocoa flavor. Where central and West Java are new land for Arabica and the flavor wait to be completly defined.
Java also grew sufficient output of good taste Robusta.