Cannabis Infused Ginger Beer

I am working on a recipe for a cannabis infused ginger beer.

I have a nice, strong, glycerin tincture made with dry sift that has a sweet, gingery flavor. I made a test batch of Alton Brown's Ginger Beer to get an idea of strength so I can adjust it from there. I plan to add the tincture to the finished drink, like a cocktail, served with a slice of lime, but I was wondering if there would be any benefit to adding the tincture before brewing? Will the yeast react with the cannabis, and if so how will it affect the finished product?

*Bump*

So far, the recipe is just to make the ginger beer, and mix it like a cocktail with tincture, serve with a slice of lime. Delicious! Still working on a way to make it shelf stable.

I'd leave the tincture till it's time to bottle, a pressure cooker is how you get shelf life.