Why are cans 12 ounces?

Cans come in many different sizes, but 12 ounces is a very common size for beverage cans in the United States. Understanding why this specific size was adopted requires looking at the history of canning and packaging technology.

The Origins of Canning

Canning first became popular in the early 1800s as a way to preserve food for long periods of time. The process involves placing food in sealed containers and then sterilizing the contents with heat. This prevents spoilage and allows the food to be stored for extended periods.

The first canned foods used heavy, thick-walled metal containers. Glass jars were also used. These early cans were primarily designed for large institutions and military rations. They were far too large and heavy for individual consumption.

The Emergence of Commercial Canning

In the mid-1800s, commercial canning emerged to meet the needs of individual consumers. Companies began canning common household foods like fruits, vegetables, meat, milk, and more. The cans were smaller and more portable than the earlier military ration cans.

These commercial cans still had no standardized sizes. Shapes and capacities varied widely depending on the contents. For example, cans designed for condensed milk were relatively tall and skinny compared to squat, wider cans used for fruits and vegetables.

Early Can Standardization Efforts

In the early 1900s, canning companies realized there were inefficiencies in producing cans in so many different sizes and shapes. Filling, sealing, and labeling machinery worked best with consistent sizes and profiles. Transportation and storage were also easier with uniform can designs. This spurred the first efforts to standardize can sizes.

In the 1920s, American Can Company, Continental Can Company, and other major manufacturers proposed standardizing tin can diameters based on variations of a basic tinplate size. They presented a plan to ration and standardize tinplate use during World War 1 which included preferred can sizes. While the standards were not formally adopted, they influenced can sizes for the next decade.

The Origin of 12 Ounce Cans

In 1932, Continental Can Company made a major advancement by developing machines to fabricate all parts of tin cans. Earlier machines had generally formed the bodies and tops separately. Continental Can’s new technology enabled cans to be quickly mass produced in a single automated assembly process.

Continental Can strongly advocated can standardization. Their machines produced cans most efficiently in certain dimensions best suited to the 12 ounce size. So while 12 ounces was not an arbitrary choice, the new technology influenced the push toward that particular capacity.

Wartime Rationing and the Tin Can Code

World War II brought renewed interest in can standardization to ration materials and streamline production. In 1942, the government instituted regulations under the Tin Can Code grouping acceptable can sizes and quantities into Classes A through G. Class B cans, for meats and non-acid vegetables, were defined as 307×406 cans holding 11 to 13 ounces.

Following the war, canners lobbied to maintain the Class B size for many fruits and vegetables as well. Consumer familiarity and packaging equipment designed around 307 cans helped solidify 12 ounces as a common food can size.

The Advent of Aluminum Cans

Aluminum emerged as an alternative to tin-coated steel cans in the late 1950s. Aluminum was lighter, stayed cold longer, and did not rust. However, early aluminum cans were not compatible with the sanitary can double seaming process required for shelf stability. It took several years to commercialize an aluminum can compatible with the filling machines and sealing processes already in place.

Once the technology was perfected, beverage companies quickly adopted aluminum for sodas and beer. Convenient pop-top openings eliminated the need for openers. But aluminum offered no cost savings or advantage over tin cans for non-carbonated beverages, so tinplate remained dominant for foods.

The Rise of 12 Ounce Aluminum Cans

In 1964, Royal Crown Cola released the industry’s first 12 ounce aluminum beverage can. Other soda and beer makers quickly followed. The 12 ounce size conveniently held a serving of soda and allowed brand differentiation through can graphics.

With a standard size in place, vending machines and coolers could be designed specifically for 12 ounce aluminum cans. Consumption was encouraged with carry handles built to hold six or twelve packs. The public embraced the cans for portability over glass bottles. Despite competition from plastic in later years, the 12 ounce aluminum can has endured as the package of choice for mainstream beer and soft drink brands.

Factors Reinforcing 12 Ounce as a Standard

Once 12 ounces was established as a standard canned size, other factors reinforced its ongoing dominance:

  • Filling equipment was optimized for 12 ounce cans
  • Aluminum can manufacturing lines produced 12 ounce sizes most efficiently
  • Consumer familiarity and preference
  • Vending machine designs standardized around 12 ounce cans
  • Supermarket shelf configurations designed around 12 ounce cans
  • Six and twelve pack carrying cartons tailored to 12 ounce cans

With all aspects of the supply chain built around 12 ounce cans, other sizes never gained much traction except for specialty products.

More Recent Can Size Innovations

While 12 ounces remains standard, can sizes have continued evolving:

  • 8 ounce “slim” cans grew popular for energy drinks
  • 16 ounce “pounder” cans used for high volume consumption occasions
  • 24 ounce “tall boy” cans for value packages

But mainstream soda and beer brands have stuck with 12 ounce cans for the majority of their volume.

Consumer Preference for 12 Ounce Servings

Another factor favoring 12 ounce cans is consumer habit and perception. Shoppers expect standard carbonated soft drinks and beer to be packaged in 12 ounce servings:

  • 12 ounces is seen as the proper serving size
  • Other sizes would provide too much or too little liquid for the right amount refreshment
  • Consumers reach for 12 ounce cans by default without considering other sizes
  • Retailers reinforce this by allocating most shelf space and cold boxes to 12 ounce cans

Without a compelling reason to change, most mainstream brands have not deviated from 12 ounce cans for their flagship products.

The Future of 12 Ounce Cans

Despite their long history, 12 ounce cans show no signs of going away. The size has proven remarkably sticky thanks to technical standardization, equipment optimization, and consumer habit. But some factors may change in the future:

  • New can shaping technologies like sleeving allow more variable sizes
  • Slim can profiles enable unique shapes and capacities
  • Sustainability pressures may favor smaller cans to reduce materials
  • Changing consumer preferences around package sizes and materials

Still, the many benefits of 12 ounce aluminum cans will likely ensure this size remains a staple of store shelves and gas station coolers for years to come.

Conclusion

In summary, 12 ounces emerged as a common canned size due to early 20th century standardization efforts, equipment constraints, wartime rationing, and industry coordination. Reinforcing factors like production efficiencies, vending machine design, distribution systems, and consumer familiarity further solidified 12 ounces as the standard can size for sodas and beer. It strikes the perfect balance of portability and sufficient volume for a single serving. Despite some niche variations, mainstream beverage makers have stuck with 12 ounce cans thanks to their advantages for both producers and shoppers.

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