My daughter (age 10), loves brewing beer with me, but not being able to consume it is a big let down. So, I got her into soda making. She loves it so much that she wants to do some of her own recipes. She really wants to make a yeast carbonated, blue raspberry soda (2.5 gallons). I noticed that there is a brand of syrup (Torani) that has that flavor.My question is, how much syrup and sugar to make 2.5 gallons?