The Dark 'n Stormy is what Bermudian sailors drink: Goslings Black Seal rum poured over ice and topped with Bermudian ginger beer. The cocktail has been served on the island since the early 1900s — Goslings has been bottling rum in Bermuda since 1860 and Barritt's Ginger Beer has been bottled there since the 1870s. The two products met in the same glass not long after.
Trademark No. 1632167: "Dark 'n Stormy" — Gosling-Castle Partners Inc., Bermuda, registered 1991, renewed.
The Trademark
Goslings holds a U.S. trademark on the name "Dark 'n Stormy" — registered in 1991, renewed since, and aggressively enforced. The trademark requires that the cocktail be made specifically with Goslings Black Seal rum; a bartender using any other dark rum is technically supposed to call the drink something else. Bermuda's commercial protection of the cocktail is part of the national identity: rum and ginger beer are the country's two characteristic beverages, and the drink that pairs them is a state export.
The trademark is uncommon in cocktail history. The Negroni is not trademarked; the Old Fashioned is not trademarked; the Manhattan is not trademarked. The closest parallels are the Sazerac (trademarked by the Sazerac Company in 2003, less enforced) and the Champagne / Cognac region names in Europe.
The Spec
Two ounces of Goslings Black Seal rum poured into a highball glass filled with large ice cubes, topped with four to five ounces of cold ginger beer, garnished with a lime wedge. The rum sits as a dark cloud at the top before it mixes — the visual the cocktail is named for. A squeeze of fresh lime is the optional addition that distinguishes the bar version from the cooler version.
Goslings Black Seal, Not Substitute
Goslings Black Seal is a blended Caribbean dark rum aged in oak — heavier and slightly sweeter than a typical Jamaican rum, with a molasses-forward profile. Substituting Cruzan Black Strap or Myers's makes a similar but distinct drink (and a legally different one, in U.S. service). Substituting a Puerto Rican or Cuban-style light rum makes a different cocktail entirely; the dark rum is the headline.
Ginger Beer, Not Ginger Ale
Ginger beer is fermented (or aggressively spiced and carbonated) and reads sharper, drier, and more peppery than ginger ale. Barritt's Bermuda Stone Ginger Beer is the Bermudian original; Fever-Tree, Q, or Maine Root all work. Ginger ale is sweet soda — it will not produce the cocktail.
Order Matters
Pour the rum into the ginger beer (not the other way around) and the dark rum will sit on top as a visible cloud. Pour the ginger beer onto the rum and the drink mixes immediately and loses its visual identity. The proper move is to fill the glass with ice, pour the ginger beer, then float the rum over the back of a barspoon.
Bottom Line
The Dark 'n Stormy is one of the simpler classics in the canon — two ingredients, no shaker, no measuring beyond a free pour. It rewards real Bermudian ingredients (or close substitutes) and a willingness to let the dark-on-pale visual happen. As a session drink for warm weather and as a defensible introduction to Caribbean dark rum, it earns its place on a list.