Which Keeps Beer Fresher, Glass or Aluminum? New Research Provides Some Scientific Insight

If you like to knock back a beer or three with friends, you might have found yourselves debating what’s better—bottles or cans. Does canned beer taste different than bottled suds? Can one kind of packaging keep beer fresher longer than another?

Researchers from the Colorado State University, Fort Collins, decided to take those armchair beer expert conversations and apply some science to canned and bottled beer to understand better how different packaging impacts the contents inside.

The study, titled “Characterizing the Impact of Package Type on Beer Stability,” was recently published in ACS Food Science & Technology, and the folks at CSU compared amber ales and IPAs bottled and canned over a six-month time frame. The beer was stored cold for a month, then at room temperature for five months. Samples were taken from freshly opened containers every few weeks, and they recorded metabolite changes.

Scientists found that IPAs were least affected by packaging differences, and water-soluble terpenes prevalent in the hops-heavy style had a more significant impact on metabolite profiles. Terpenes prevent oxidation and bind to amino acids, keeping them in the beer longer. Terpenes also play a prominent role in the flavor profile of beer. Brewers add hops to beer to add flavor and complexity, but they also provide additional freshness.

On the other hand, Amber ales saw more metabolite discrepancies based on packaging type. Canned amber ales' metabolite profile changed more than amber ales packaged in bottles. They attributed the variance to the water solubility of the compound and a phenomenon known as “flavor scalping,” where packaging materials either absorb volatile flavors or impart an unpleasant taste to the item. Linings used to coat the inside of aluminum cans leech terpenes with lower water solubility, such as humulene. 

The study primarily focused on the relative stability of stored beer over time when comparing bottles and cans. Researchers noted that they were not comparing the actual taste of the beers, so determining the best packaging material is outside the scope of the study. Instead, the study suggests more work in understanding the mechanisms of glass bottles and aluminum cans. The study's authors also recommend further studies that account for changes in taste. Still, the data gives brewers some knowledge to consider when making packaging decisions.

And, it also might give those bearded beer fellas a little more ammunition in the great bottle versus can debate. Either way, at least they're both infinitely recyclable.