How a reed diffuser works
Updated
On this page8
The mechanism
Liquid climbs the reed by capillary action and evaporates from the part standing in the air. Scent throw is therefore governed by how much reed is exposed and how fast the liquid moves up it, not by how much is in the bottle.
Neck diameter is the throttle
A narrow neck holds fewer reeds and slows evaporation from the liquid surface; a wide one does the opposite. It is the single control you have over intensity after the formula is fixed, which is why neck finish is not a packaging detail here.
The liquid has to be thin enough to climb
A blend thickened for any other reason stops wicking, and the product simply does nothing while looking perfect. Viscosity is a functional specification in this format rather than a matter of feel.
It runs for weeks with the neck open
That is the defining fact of the format, and the reason the rest of this property reads differently from a bottle of cleaner. Whatever closure ships on the bottle is off the bottle for the product life.
Reeds are consumable
They clog with the heavier fraction of the blend and throw less over time, which is why flipping them helps and why replacement reeds are a real line item. Say so, because a customer who thinks the oil is dead will not reorder.
Design the bottle around the mechanism
Enough height for the reeds to stand, a neck sized for the throw you want, a flat base for stability, and a closure for shipping rather than for use. Everything else on this shelf follows from those four.
Everything else on this page follows from evaporation
Neck diameter, reed count, blend viscosity and bottle height are not four separate choices, they are four terms in one rate. Change any of them and the product performs differently, which is why the format has to be tested as a whole rather than ingredient by ingredient.