What do perfume concentrations mean? This is a topic that is often misrepresented or misunderstood, so let's hear from our perfumer, Pia Long: "In perfume, the solvent is like the canvas and the fragrance oil is like the paint – or in a more prosaic metaphor, the solvent is like the water in your instant coffee and the fragrance oil is like the granules. All of it together is the “perfume”, there are no unnecessary ingredients."
Just like a watercolour versus an oil painting; the tonality and character of a perfume goes hand-in-hand with its concentration in solvent – the two go together inseparably.
If you take a fragrance that was created to be a “watercolour” at 10% concentration, and instead increase it to 20%, you are likely to ruin the impression intended, and it may even smell unpleasant. You won't get a "stronger perfume" or a "long lasting perfume" by doing that. All you'll do is distort.
The perfume oil itself has to be designed to be right within a certain range of concentrations. Occasionally you'll get a fragrance that could work in low concentration and a much higher one, too, but that is also likely to have been an intentional decision by the perfumer and isn't simple to do.
Higher concentration of perfume oil in solvent does not automatically mean that the perfume will be longer lasting or project more. It's the types of ingredients used in the fragrance oil that determine that. You can have extremely high impact materials which are dosed low and still smell super strong, or you can have low impact materials with a faint smell that are dosed super high.
A perfume is experienced in time (how long it lasts) and space (how diffusive it is), and you can plot those two on a chart and see if you have an eau de cologne (huge, diffusive, short-lived), or a classic perfume (lots of mid and base notes; long-lasting, but not hugely diffusive at first until the heavier parts of the perfume warm up on your skin and lift off).
In our perfumes, we wanted the time and space axis to be fairly evenly balanced. A scent strong enough to be noticed, which also doesn't abandon you after just a couple of hours. Depending on the type of ingredients and olfactive impression desired, we chose the following concentrations for Eau de Boujee:
Verdant = 15% of perfume oil
Gilded = 20% of perfume oil
Quir = 20% of perfume oil
Queen = 20% of perfume oil