Pure-Pak shipped the milk bottle flat and formed it at the dairy

Milk distribution was built around glass: strong and reusable, but heavy, breakable, and bulky even when empty. The return loop was part of the cost of selling milk.

Van Wormer's 1915 folded-blank carton attacked the empty-container problem. IFT describes Pure-Pak's key feature as delivery flat to be folded, glued, filled, and sealed at the dairy, saving storage and delivery compared with preformed glass bottles.

The hard part was machinery. The Henry Ford notes that after 1937 mechanized production made disposable wax-coated folded cartons inexpensive and indispensable liquid containers.

Ship blanks, not empty bottles

It separated package manufacture from package volume: blanks occupy little space until the filling site.

The gable top doubled as closure and spout, avoiding a separate cap system.

The machine, not the carton alone, made dairies able to switch from returnable bottles.

Do not transport emptiness if the shape can be created near filling. Moving a package as a blank can change the economics of the whole product flow.

Pure-Pak-style gable-top cartons became a durable liquid-packaging standard. Later polyethylene coatings, aseptic systems, and larger sizes improved the format, but the original logistics insight remained: store and ship the future container flat.