I'm a relative newbie to cheesemaking, but I did go the the website for the Brie recipe you used. As far as the color--no idea. But for 4L milk shows a "few grains" of starter culture. Depending on your interpretation of that, it could be very, very little. Also the recipe has you aging in the refrigerator in a plastic bag. I think that temperature of around 40 degrees may also be too cold.