western coffee, only raw bean roasted, grind to powder then add hot water become black coffee
add milk/sugar become latte/cappucino etc
hainam coffee raw bean roasted adding butter & sugar, grind to powder then add hot water become black coffee
add condensed milk/sugar become kopi/kopi c etc
different beans also used, western more arabica, while hainam coffee think mixed both arabica & robusta.
roast level western more light, while hainam coffee quite dark, hence the bitterness.