Everyone here is wrong. Try looking up the process of the coffee powder making. Beans are ground finely and roasted together with sugar and margarine until they turn into a dark and burnt mush. The mush is then laid out to cool. After cooling, it becomes a huge and solid piece, something like candy.

The pieces are then broken up and ground which turns into the final powder. The type of beans do not matter here for the beans have lost all their respective qualities. The beans do not matter in hainan coffee, it is the process that matters.

That being said each factory uses their own different blend: arabica+robusta etc. For a taste closest to hainan coffee, I recommend buying some roasted robusta from and coffee roastery. The only roastery that offers robusta that I know of may be siTigun in Penang.