Orange Bitters
Orange bitters predate Angostura as the original cocktail bitters — 19th century cocktail books call for orange bitters as the default. They fell out of fashion mid-20th century (Prohibition killed many producers) and were revived by Gary Regan's reformulation in 1997 (Regan's No. 6 specifically developed to fill the gap). The craft cocktail revival of the 2000s canonized orange bitters alongside Angostura and Peychaud's as the essential three.
Flavor Profile
Citrus brightness without citrus juice. 'Add citrus brightness without adding citrus volume.' Particularly useful in stirred drinks where fresh citrus would disrupt water balance. Orange, dried peel, warm spice undertone.
Key Producers
More citrus-sweet; slightly simpler profile
Spicier, more structured; the Angostura house approach to orange bitters
Spicy, complex, dry; the standard cocktail bar orange bitters