I would have lit this photo from behind just as you did, although it would have been nice if it were a little less obvious the flash was behind the booze bottle. That and the odd fade of the background detract from the image.
Don't let it get you down though - best composition yet! Without critiquing your style it's an easy 10. The odd lighting and the border that matches the color of the coffee when the subject of the photo is obviously the booze are the only things imho that kept this image from earning a ribbon for its photographer.