<P> The popularity of canned drinks was slow to catch on, as the metallic taste was difficult to overcome with the interior liner not perfected, especially with more acidic sodas . Cans had two advantages over glass bottles . First for the distributors, flat - top cans were more compact for transportation and storage and weighed less than bottles . Second for consumers, they did not require the deposit typically paid for bottles, as they were discarded after use . Glass - bottle deposits were reimbursed when consumers took the empties back to the store . </P> <P> By the time the United States entered World War II, cans had gained only about ten percent of the drink container market; this was drastically reduced during the war to accommodate strategic needs for metal . </P> <P> In 1959, the recyclable aluminum can was introduced to the market in a 7 oz . size by the Adolph Coors Company . Also in 1959, Ermal Fraze devised a can - opening method that would come to dominate the canned drink market . His invention was the "pull - tab". This eliminated the need for a separate opener tool by attaching an aluminium pull - ring lever with a rivet to a pre-scored wedge - shaped tab section of the can top . The ring was riveted to the center of the top, which created an elongated opening large enough that one hole simultaneously served to let the drink flow out while air flowed in . In 1959, while on a family picnic, Mr. Fraze had forgotten to bring a can opener and was forced to use a car bumper to open a can of beer . Thinking there must be an easier way, he later stayed up all night until he came up with the pull tab . Pull - tab cans, or the discarded tabs from them, were also called "pop - tops" colloquially . In Australia these were colloquially known as "ring - pull". Into the 1970s, the pull - tab was widely popular, but its popularity came with a significant problem, as people would frequently discard the pull - tabs on the ground as litter, or drop them into the can and risk choking on them . These problems were both addressed by the invention of the "push - tab". Used primarily on Coors Beer cans in the mid-1970s, the push - tab was a raised circular scored area used in place of the pull - tab . It needed no ring to pull up . Instead, the raised aluminium blister was pushed down into the can, with a small unscored piece that kept the tab connected after being pushed inside . Push - tabs never gained wide popularity because while they had solved the litter problem of the pull - tab, they created a safety hazard where the person's finger upon pushing the tab into the can was immediately exposed to the sharp edges of the opening . An unusual feature of the push - tab Coors Beer cans was that they had a second, smaller, push - tab at the top as an airflow vent--a convenience that was lost with the switch from can opener to pull - tab . The "push - tab" was introduced into Australia in the early 1980s and was locally known as "pop - tops". </P> <P> The safety and litter problems were both eventually solved later in the 1970s with Daniel F. Cudzik's invention of the non-removing "Stay - Tab". The pull - ring was replaced with a stiff aluminium lever, and the removable tab was replaced with a pre-scored round tab that functioned similarly to the push - tab, but the raised blister was no longer needed, as the riveted lever would now do the job of pushing the tab open and into the interior of the can . </P>

Who invented the flip top for soda cans