Elderflower liqueur.

This is something of a work in progress rather than a finished recipe. I would love to know your thoughts of ideas.

I have simply filled a jar with vodka and elderflower heads. It has been steeping for a week, but the top flowers simply float out of the vodka and go brown. I am slightly worried that this has ruined it as it is beginning to bubble. I have now placed a wax paper disc onto the top to attempt to weight the flowers down into the vodka. I am planning on straining it after a month and then adding sugar to taste.