Yes, bitter chocolate and unsweetened chocolate are generally considered the same thing.
According to U.S. regulations, the ingredient known as chocolate liquor can also be labeled as chocolate, unsweetened chocolate, baking chocolate, or bitter chocolate. This ingredient forms the base of dark and milk chocolate and, contrary to what some might think, contains no alcohol or vegetable fat. The "bitter" and "unsweetened" descriptors refer to the absence of added sugar.
This means when a recipe calls for unsweetened chocolate, you can confidently use bitter chocolate and vice versa. Both are made of pure chocolate liquor, which is the result of grinding cocoa beans into a liquid state.
Therefore, the terms are interchangeable in most culinary contexts.
