For most craft beer, the can does not change what is in the liquid, it changes how long that liquid stays correct and how cold it arrives at your mouth. The beer in a can and the beer in a bottle are the same beer, brewed in the same tank and filled from the same bright tank, and the difference is the container it travels in. A can is sealed against light, takes almost no oxygen through the closure, and is cheap to ship and stack, and those three things together are why the can is the better package for beer that is going to sit in a fridge for a while. There are a few real differences at the margins, and a couple of breweries genuinely do put a different beer in a can, but for the beer itself, the answer is that the can mostly buys you shelf life and cold, and the flavour difference you may or may not notice is the difference between beer that has been lightstruck and beer that has not.
Why Cans Won, And Why Breweries Switched
Cans were not a craft invention. The first beer cans went on sale in the United States in the mid nineteen thirties, and for most of the twentieth century the can was the container of cheap lager, the format you got because it was inexpensive and it did not break. What changed in the craft era was not the can but what went into it, so that a can of a hop-heavy pale ale could be bought next to a bottle of the same beer and the can was the one people reached for. Once a brewery has fans who want a portable, cold, lightproof package, the can stops being a budget container and starts being the format the brewery leads with, and after that it is often the flagship, because cans are cheaper to produce, lighter to ship, easier to chill and stack in a fridge, and they carry a printed surface that takes artwork.
The switch has a practical driver on top of the marketing one. A brewery that wants to sell beer in British Columbia and to people further away needs a package that survives a truck and a warehouse, and aluminium takes that better than glass. A bottle that gets a single bad knock in a pallet is lost, and a can just dents. And a can goes from warm to cold in a fridge far faster than glass, which is not a trivial point, because most craft beer is drunk well below cellar temperature, and a can that was properly chilled drinks noticeably fresher than a bottle that has been sitting at room temperature for an hour.
The Two Ways A Package Can Change A Beer
There are really only two ways packaging affects the liquid, and both are about what gets in or what light hits it. The first is oxygen, because once beer is packaged it is a sealed chemistry problem. Beer is brewed in an anaerobic environment, filled into a tank under cover of carbon dioxide so that no oxygen enters, and from that point the goal is to keep it that way. Every time a bottle is opened, or a can is filled with a burst of gas, or a closure lets in a little air, a small amount of oxygen gets in, and in a beer with any residual sugar and strength that oxygen will eventually do damage. In a light beer the damage is a thin, papery, bready note. In a hoppy beer it is a skunky, horseshank smell. Neither is the fault of the style, they are the fault of handling, and the packaging is a large part of how much handling the beer sees.
The second way is light. Lightstruck beer is the single worst flavour a package can cause, and it is caused by ultraviolet light acting on compounds in the hops. The result smells of skunk or wet cardboard, and it is irreversible. This is why brown glass bottles exist at all, because amber and brown glass filter out most of the light that does this damage, and it is why a clear or green bottle is a poor choice for a hoppy beer. A can, being opaque aluminium, blocks essentially all of the light, which is the clearest technical reason a can of an IPA is very likely to taste fresher and cleaner than a clear bottle of the same IPA that has sat on a shelf under fluorescent lights. Our piece on the chemistry of hops covers why that reaction smells so bad.
Canned Versus Bottled, Side By Side
| What you notice | A can | A bottle |
|---|---|---|
| Light protection | Essentially total, since aluminium is opaque | Partial, and depends on the glass colour |
| Oxygen ingress | Very low, and the fill is fast and sealed | Slightly more, and higher in a bottle with headspace |
| Chilling speed | Fast, aluminium pulls heat quickly | Slow, glass insulates from the fridge |
| Shipping and durability | Light and stackable, survives knocks | Heavier and breaks, but a larger format is available |
| Shelf life | Often a year or more, best drunk fresh | Often similar, but the date matters more in a bottle |
| Serving | Cold, straight from the fridge, pours cleanly | Better for sharing, and often larger single formats |
| What is inside | The same beer, in almost every case | The same beer, in almost every case |
When A Brewery Does Put A Different Beer In The Can
Almost every brewery fills the same beer into the can and the bottle, but there are real exceptions worth knowing. A nitro beer cannot be served from a standard tap without a nitrogen system, so nitrogenated versions are frequently packaged as a can or a widget bottle that pours the cascade in the glass, and the nitrogen carbonation is part of the beer rather than a packaging trick. A small number of breweries also can a beer specifically because the can handles it well, such as a heavily hopped pale ale or a barrel-inspired beer that they know will be enjoyed within a window, and some will release a can-only batch or a rotating series in cans where the format suits the release. Finally, larger formats and single serves exist side by side, so a 355 mL can and a 500 mL bottle of the same lot are both the same beer in different amounts. The point to hold onto is that a can is not a different recipe by default, and if a brewery says it is, that is worth asking about specifically.
The Date And The Shelf Life Question
The date printed on a can is a best before rather than an expiry, and it is generous on purpose. Most canned craft beer is at its best within months rather than weeks, and a well made, well packaged beer will still be clean well past its printed date if it has been kept cold and dark, because the flavour that fades first in a light, hoppy beer is the fresh hop aroma, not safety. That means a can stored in a fridge is fine for a good while, and a can that has been in a hot car or in the sun for an afternoon is not. The practical advice is to buy cold, store cold, and drink the freshest can first rather than the one that has been at the back of the fridge for a month. The old practice of saving the good bottle for last is worth keeping for bottles that have real age in them, but for a canned pale ale the freshest can is the best one.
What To Ask, And What To Buy
- Ask whether the can and the bottle are the same beer, since for most breweries they are, and the ones where they differ are the interesting exceptions.
- Look at the date and buy the freshest can you can, because a hoppy beer loses its aromatic hop character faster than it loses any other flavour.
- Store it cold, and treat a can that has been hot as a can to drink now rather than to save, since heat is what does the damage rather than the age.
- Compare a canned and a bottled version of the same brewery's pale ale in a blind taste, because the difference is usually smaller than the marketing implies and it is more honest to form your own view than to trust the package.
- Choose the can for hoppy, light, cold beer and the bottle for a larger format you will share or for a beer you want to open slowly, and let the beer decide the package rather than the other way round.
The Health And Practical Bottom Line
The alcohol in a canned beer is exactly the alcohol in a bottled beer, since it is the same liquid, so a can changes nothing about how much you are drinking. A standard drink in Canada is a set amount of pure alcohol, and it takes the same volume of canned beer as bottled beer to reach it, so there is no lighter or safer option hiding in the packaging. On gluten, beer made from barley contains gluten, and putting it in aluminium does not change that, so a canned beer is not suitable for a person with coeliac disease. The one genuine practical advantage of the can is the single serve, because a 355 mL can is a clearly measured unit that is harder to overpour than a bottle you pour and pour and pour, and for that reason the can has become the default format for a beer meant to be paced rather than savoured. Everything else the can does is about light, oxygen and cold, and those are the three reasons it is usually the better package for the beer this blog is about.
