it all depends on how weak or strong the flavor is. some super concentrates are best go 2 to 3 percent. Other flavors are pretty weak and need a much higher percentage. It doesn't mean flavors are bad just some require a higher percentage than others. then of course some people have more sensitive pallets then the rest of us. So flavoring is really subjective but you can follow basic guidelines and tweak to your own preference. That's one of the enjoyments in doing it yourself