what really makes all the difference in the color and body of a beer, since most beers are brewed with barley is how darkly the malt has been roasted. The darker the roast, the darker the beer that results from this ingredient.
Surprisingly wonderful review of many different styles of beer. This guy, Garrett Oliver, knows his beers.
best damn dark beers I've ever tasted!
I'd never have the patience to do this, but it was interesting to learn.