Can, bottle or draft? Which beer keeps its flavour best

For years, the glass bottle was seen as the more “premium” option, while the can was associated with cheaper beer. Draft beer, meanwhile, is almost automatically regarded as the freshest and most flavoursome choice. The reality is more complex: quality depends chiefly on light, oxygen, temperature, time and—in the case of draft beer—the maintenance of the dispensing system.

Why the can has an important advantage

Spanish beer judge Agus Blanco, one of the most active judges in the Beer Judge Certification Program, notes that beer’s main enemies are light, heat and oxygen. Here, the can has a clear advantage: it is opaque and does not allow light to reach the beer.

Modern cans have an inner lining that keeps the beer separate from the aluminium. The old belief that metal “comes through” in the taste therefore does not match the way beer is packaged today.

Also of interest: Beer, Coca-Cola or Zero? What we are really putting into our bodies. (in Greek)

What happens with the bottle

The bottle remains excellent packaging, especially when it is brown. Glass, however, does not offer the can’s complete protection from light. Green, and especially clear, bottles allow more light through. That increases the risk of the characteristic flaw brewers call light-struck, or a “skunky” flavour.

Interestingly, part of the difference we think we taste may also be in our minds. In a 2016 study, consumers rated beer more highly when they knew it came from a bottle. But in a blind tasting, the difference disappeared: 13 preferred the can, 12 the bottle and 4 noticed no difference.

And what about draft beer?

This is where things become even more interesting. The keg also fully protects beer from light. In a properly regulated closed system, contact with oxygen is limited as well.

In a busy bar, where kegs are emptied quickly and kept continuously cold, draft beer can indeed arrive exceptionally fresh in the glass. The Brewers Association notes that when beer is handled correctly from brewery to glass, draft beer can offer one of the freshest and most flavoursome experiences.

There is, however, one major caveat: the lines.

Beer residue, yeast, proteins and microorganisms can form biofilm in the lines. The result may be buttery, sour or otherwise undesirable flavours. The Brewers Association recommends cleaning the lines at least every 14 days.

A neglected draft system, therefore, can be worse than a properly stored can.

So which one wins?

There is no absolute winner.

For protection and storage: the can has the technical advantage.

For special beers that mature in the bottle: the bottle can be part of the beer’s own character.

For freshness at serving: a well-maintained draft beer, from a keg that is emptied quickly, can offer an excellent experience.

There is, however, one simple way to make the comparison fairer: always serve beer in a clean glass. That releases its aromas and avoids the influence a can or bottle can have on our perception.