- Combine sugar, salt, corn syrup and water in a heavy saucepan.
- Stir over low heat and add vinegar and butter. Continue to cook, stirring only occasionally until mixture reaches 265 F.
- Remove from heat and stir in rum. Pour into lightly buttered pan, with a heavy spatula, work the candy mixture from edges towards center.
- When cool enough to handle, butter your fingers and put candy between hands until it becomes hard to pull.
- Pull into a 2.5-inch diameter rope. Cut with scissors and wrap individually.
- Butter Rum Taffy is ready!