My favorite beers come in bottles and in cans. I always buy it in bottles because I've heard that cans negatively impact the flavor of the beer.
Is this true?
If so, how does it work?
First, I love this question because it is actually interesting.
I researched this when I noticed that bottled coke tasted so much better than canned coke. Cans keep out all light so the contents actually never become tainted. The reason that most like bottled over canned is because they like the taste with those impurities. Some complain that they can taste aluminum with cans, but this is more than likely in their head since cans are lined with a thin layer of plastic.
I like certain beers better in cans and certain ones better in bottles. I would try both :)
As a member of a Studentenverbindung, having one principle of scientia, we of course tested this a long time ago with around a dozen or maybe a bit more testers.
We poured beer from the same manufacturer (fresh batch) into glasses and had people taste them, and for every glass (everyone had multiple ones) they had to say if they think it was from a bottle, a can, or a keg, and which tasted better.
After around 50 or 60 glasses, there was no statistical evidence whatsoever that any of the three could be identified, or tasted better.
From my personal experience though, I always think that a keg is better than a bottle is better than a can. But why is that so? I only have the theory that due to the feeling of the container you drink from, your taste is altered (just like food with the same flavour/taste somehow tastes different, with a different texture). Additionally I think the amount of beer that flows into your mouth is different, as well as maybe the turbulence, causing a different amount of carbon dioxide (or nitrogen, depending on your beer culture) to leave the beer before you can actually taste and swallow (which again changes the texture).
I heard a quote from the revered Charlie Bamforth, who basically said that packaging beers in cans was a far better way to preserve the beer from brewery to customer than packaging in bottles, but bottles are still more aesthetically pleasing to the customer, so they are usually preferred. And that's from a man that has been head of Quality Assurance for a number of years.
It's purely in the mind - there isn't any real change to the beer. If anything, the difference with bottled beer is that the canned version is better preserved.
I actually do not think that the can itself changes the taste of the beer as much as the beer placed in the can may be a little different. I think that the real difference is going to be between keg beer and can/bottle beer.
Canned/bottled beer has a longer shelf life than keg beer. Canned/bottled beer has a shelf life of roughly 45-60 days, whereas a keg is only 25-40 days 1.
This means that worst case scenario for comparison you could be tasting a 2 month old canned beer versus a 3 week old draft. It can cause a difference in taste, there is a "freshness date" after all. (See this excellent answer from @mdma for more information on what happens as beer ages)
But where does this date come from? Almost all imported retail beer is pasteurized. The reason for pasteurizing the beer is from a business standpoint. It basically allows the beer to last longer and be shipped at room temperature (this applies to kegs, cans, and bottles).
An alternative to the pasteurization process is bottle conditioning. Most domestic beers follow this path. Essentially this process involves beers being sterile filtered and chilled to the point that any surviving bacteria, which could ferment the beer, become dormant 2.
So basically the probability that the beer begins to ferment is higher over time. A canned beer and a keg beer can taste the same if they both left the brewery at the same time, and both experienced the same conditions during the time it took them to reach you. It is just that kegs have a better chance of taking less time and of being better preserved.
From a practical standpoint though, bottles can cause broken glass, kegs weigh close to 50 lbs. full, and cans allow for shotgunning. Make sure your container of choice fits your environment :)
I don't know how/if the actual storage in cans vs bottles affects the taste, however you should expect that they are not filled with the same beer.
Many companies will have different production logistics, and the can will often come from a different site than a bottle of the same brand, and will have slightly different water and production process, so the beers will taste slightly different before they even touch the can; and they may even have intentionally different production and additives.
If you are drinking beer directly from the can or bottle, then one measurable difference is the speed at which it warms up while you are drinking it. As glass is an insulator and aluminium is a conductor, you'd expect the can to be more efficient at transferring heat from your hand and the environment into the beer. So a glass bottle should keep the within the optimum temperature range for longer than the can.
This result is backed up by some research done by students at Worcester Polytechnic Institute, which compared the rate at which refrigerated liquid warms up to room temperature in glass and aluminium bottles. The heating rate differences should be even more noticeable if the bottles were in contact with a body temperature heat source.
This effect can be minimised by insulating the can using a stubby holder/beer cozy. In another experiment comparing cans held in a person's hand, over a 30 minute period an uninsulated can rose in temperature by about 14°C while the insulated can rose only 3°C.