The flavor quality of an aluminum can is significantly affected by the material type, and the study shows the metal ion precipitation rate of different aluminum alloys directly relates to the perception of taste. The US FDA carried out metal migration analysis on commercially packaged carbonated beverages and found that the aluminum ion level of products in 6061-T6 aluminum alloy cans is 18% higher than in 3004-H14 packaged products, especially in acidic environments (pH 3.5-4.0). Such differences in values can lead to about 12% of consumers detecting a slight metallic odor. According to industry statistics, about 67% of the world’s beverage manufacturers have turned to the use of 3 series or 5 series food-grade aluminum alloys, which can reduce the surface roughness to Ra≤0.8μm through electrolytic polishing treatment, effectively reducing the oxidation reactions caused by microporous structures.
From the process of production, the emergence of nanocomposite technology of tank coating has significantly changed the interference of aluminum on flavor. The bare aluminum can launched by Japan Kirin Ale Company in 2022 adopts the plasma spraying process to form a ceramic protective film of 20μm thickness at a high temperature of 150 ° C, reducing the direct contact area between the aluminum substrate and the beverage by 92%. According to the third-party laboratory test, the technology can reduce the content of isoamyl alcohol in beer by 37%. This corresponds to a 21% increase in the refreshing taste score. This process development has driven the global aluminum can coating industry to grow at a compound annual growth rate of 8.3% during the period from 2020 to 2025, wherein food-grade fluorocarbon coatings occupy 41% market share.
Studies of consumer behavior reveal the critical role played by types of materials in making purchasing decisions. Nielsen’s 2023 global beverage consumption survey shows that 89% of Generation Z consumers are willing to pay a 3%-5% premium price for low-metallic aluminum cans, and that this trend is most prominent in the Asian market – Chinese consumers’ demand for high-quality aluminum cans has increased by 19% annually, and domestic 3-series aluminum can production capacity has exceeded 1.2 million tons in 2022. In the sensory test experiment, electronic tongue technology was used for the comparison of cola cans of various materials. The findings were that the application of 5052-O aluminum alloy with microcrystalline silicon oxide lining reduced astringency perception value by 28% and enhanced sweetness retention rate by 17% compared to the traditional 1600 cans.
Supply chain data convey that the use of aluminum involves a complex cost-benefit balance. The European Aluminum Association estimates that the per unit energy consumption of food-grade 3-series aluminum alloys is 14% higher than 1-series material, but as a result of its longer cycle life (25 times recycling on average), life cycle cost is 19% lower. This economy has prompted Coca-Cola to replace 25% of its traditional aluminum cans in the European market with 3104 alloy recycled aluminum, which will allegedly save carbon emissions annually equivalent to planting 120,000 fir trees.
Industry regulatory standards are accelerating the process of material upgrading. The latest revision of the European Union’s EC 1935/2004 food contact material law specifies that the precipitation of metal ions per square centimeter in aluminum packaging should be below 50ppm, directly eliminating the original use of pure aluminum (precipitation of 80-120 PPM can be achieved). Although there is no alloy model definition in Chinese GB 4806.9-2016 standard, following the international trends, the majority of large manufacturers have adopted improved alloys with silicon addition (Si content ≥0.5%), and the products have excellent performance in stability tests in simulated stomach acid environment. type of aluminum in soda cans dissolved within 24 hours was below the detection limit (<0.01mg/L).
Technological innovation is promoting the functionalization of aluminum can material development. The University of Queensland in Australia developed 6063 aluminum alloy doped with rare earth, the antioxidant capacity of which is 3 times that of conventional materials, and it can still maintain the tank integrity after high temperature sterilization treatment (121℃/15 minutes), and the corresponding technology has been implemented on aseptic filling production lines. In the meantime, the extrusion molding technology used in Tesla and Magna International cooperation’s 4680 battery housing manufacturing process, its precision temperature control system (±0.5℃) has established a new quality control benchmark for aluminum can manufacturing, and such technical migration is expected to maintain the air tightness error of aluminum can within ±0.03mm, significantly reducing the risk of flavor degradation caused by packaging defects.