Hi, Sucoi.
Well, maybe I can't describe a little bout it. Sumatra Coffee mostly famous from 3 district in Sumatra:
1. Nanggroe Aceh Darussalam Province(Gayo Arabica)
2. North Sumatra Province(Karo Arabica, Linthong/Lintong Arabica, Mandheling/Mandailing Arabica, Sidikalang Arabica)
3. Lampung(Robusta)
All of this type of coffee are plant in Bukit Barisan Highlands(in english: Mountain Chain Highlands) expanding from Gayo(Aceh) ended at Lampung Province, it's about 1650 km. you can find the location from Google Earth I think.
For the flavor detail maybe you can browse my album.
Describing coffee by region is obviously helpful, but also can be misleading. Every crop is different - sometimes very different so your mileage may vary.
That being said, Sumatrans tend towards earthy, heavy-bodied, rich flavors. Usually low acidity.
Wow...learning quite a bit about coffee today. Not a hardcore coffee drinker..usually prefer cold coffee with ice-creams but certainly intrigued to try out newer stuff...Thanks for the information you'll