All About Bitters (Part 1) in Spirits & Cocktails Posted December 12, 2008 I just got my hands on a bottle of Fee Brothers Whiskey Barrel Aged Bitter. My bottle "achieved oaken maturity" in 2008, whatever that means.[snip]So what are these Fee Brothers bitters good for? Are they ever a good substitute for Angostura? And why does something aged in a bourbon barrel need extra color added?←I love the Fee Brothers barrel aged in whiskey sours and I've also found they're quite good in a Manhattan although for that application I go with 2 dashes Angostura and one dash of the Fee's.I really like the warm spiciness of them from the cinnamon, cloves, allspice, etc. Seems to complement the flavors of bourbon.As for your comment on the Old Fashioned, maybe dial down the amount of sugar you're using to account for the perceived sweetness of the Fee's?