Tiring to produce an American pale ale with citrus/marmalade hopping (citra /amarillo hops seems the way to go ) but what can/should one use as a bittering hop. And do bittering hops add significant flavour or just bitterness?
Bittering hops will add some flavour yes. The usual thinking is if you are boiling for 60 minutes, the hops added at the beginning won’t provide that much flavour but more bitterness. Then you add some at the 30 minute mark and they’re considered for both flavour and bitterness as they have less flavour boiled off. Then you add some in the last minute and that’s just for flavour and aroma and not enough time to convert into much bitterness. Dry hopping later after fermentation gives another more grassy, herbaceous type of flavour as well as the flavours from the oils and no measureable bitterness. In reality you get a bit of flavour and bitterness with every addition (eat a hop pellet, its bitter) but the standard way of looking at it is the hops added at the beginning of a 1 hour boil won’t be adding that much flavour due to the oils being boiled off so add some more at the 30 minute mark to retain some from hops you;re using to bitter the beer with.