Pumps, droppers and what the pack has to do
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In most categories the dispenser is a convenience. Here it is part of the preservation system and part of the stability plan, which means it is a formulation decision wearing a purchasing decision's clothes.
Four delivery formats, four risk profiles
An open jar is the hardest case. Fingers enter it and air sits on the surface, so the product is re-inoculated on every use and oxidized continuously. It is also what customers associate with a rich cream.
A tube removes fingers and most air exchange, and suits anything from a light lotion to a thick cream.
A pump removes fingers entirely but draws air back into the bottle as it empties, so the product meets progressively more oxygen over its life.
An airless system does neither: a follower plate displaces the product and the contents never meet the atmosphere.
Viscosity decides what will work
Every dispenser has a viscosity window. A dropper needs the product to flow through a narrow orifice under gravity. A lotion pump has a range above and below which it will not lift or will not stop. An airless pump needs the product to follow the plate without cavitating.
Which is why a formula that thickens slightly between development and production can make packaging you already own unusable. Measure viscosity at a defined temperature, specify a range, and check it against the supplier's stated window before ordering.
What a pump actually is
An assembly of several materials, including a spring, a gasket and a dip tube, all of which the formula sits against for two years. Low pH products can corrode metal springs, and some formulas swell or degrade gaskets.
So a pump is part of the compatibility study, not an accessory to it. Test the formula in the actual assembly.
Choosing
Start from the preservation and stability requirements, then from viscosity, then from appearance. A marginal challenge result or an oxygen-sensitive active removes the jar from your options regardless of how the brand wants to look.
Where the requirements leave you a genuine choice, take the one the customer prefers. Where they do not, the chemistry is not negotiable and the packaging is.
Finishes we stock, and what dispenses from them
