substitute for bittersweet chocolate?

Would semi-sweet chocolate be a reasonable substitute if a chocolate mousse recipe (for a cake filling) asks for bittersweet? Thanks!

you can substitute semi sweet for bitter. Since semi has more sugar than bitter, your mousse will end up sweeter, and with a lighter chocolate flavor.

Some people might reduce the sugar called for in the recipe to make up for using semi, but that may change the texture of the final product.

Great! Thanks!

Also, a few drops (or more) of coffee or brandy will add a nice dimension to your mousse, and will highlight the flavor of the chocolate rather than giving it an altogether new flavor.

I've done substitutes in the range of 3/4 semisweet and 1/4 unsweetened chocolate, if you want to get closer to the flavor of bittersweet.