How much cologne should one add to get a decent scent in the soap? Or is it all subjective? I do not have access to any of the little vials of scent oils.
really depends on the essential oil you want to use. When I make batches of soap they're usually 2 pounds which is maybe 15-20 bars and for oils like cinnamon or clove i can put 5 drops in and get a nice smell but for things like jasmine a whole 1/2 ounce bottle does almost nothing...so really you have to do a kinda trial and error thing or research what other people have done.