
Crème de mûre is a sweet blackberry liqueur made by macerating blackberries in spirit and sweetening heavily.
It is often drizzled over a finished drink so the color bleeds down through the ice, as in the Bramble. Shaken in, it adds fruit, sugar and a deep purple color.
Crème de cassis
The usual stand-in, in the same amount. Usually a little sweeter, with tarter blackcurrant flavor and a deeper purple color.
Another crème de mûre
Swaps straight in, but sugar varies widely between brands, so taste.
Chambord works measure for measure. It is less sweet than most, so add a little syrup if needed.
Blackberry eau-de-vie or brandy
Eau-de-vie is unsweetened: use half the measure plus 1½ barspoons of 2:1 syrup per 15 ml of crème de mûre. American blackberry-flavored brandy can be sweetened, so try it without syrup first.
It will not spoil, but once open the fruit aroma fades, and the color fades with it. Keep it closed, cool and out of the light. A long-open bottle tastes flatter but is still fine to use.