Does draught beer taste different from bottled beer?

Temperature, carbonation and the route through the line differ for a keg from those for a bottle, and together they determine most of the taste experience.

The Brewers Association recommends a serving temperature for draught beer of 34 to 38 degrees Fahrenheit, about 1 to 3 degrees Celsius. A bottle from the fridge is usually around 5 degrees, a bottle from the cupboard considerably warmer. Colder beer gives less aroma and more freshness.

Then there is the carbonation. Draught beer is poured into the glass under pressure, which gives a different head than opening a bottle.

Draught beer is usually at 2.2 to 2.8 volumes of carbon dioxide, with a range of 1.2 to 4.0 volumes for special styles.

To keep that content in the keg, carbon dioxide pressure is applied. The Brewers Association gives about 11 psi as working pressure at 2.5 volumes and 38 degrees Fahrenheit. If the pressure is too low, the beer loses its fizz; if it is too high, the glass foams over.

With a bottle, the carbonation is fixed at the moment of bottling. What you taste afterwards depends on the storage temperature and on the way you pour.

A beer line becomes overgrown on the inside with yeast and bacteria, and the Brewers Association therefore advises cleaning every 14 days.

If this is neglected, you will taste it: the beer turns sour or musty, and the head collapses faster. With a bottle this is not an issue, because the beer goes from the brewery straight into closed glass.

Anyone who taps at home or at a party runs the same risk. A rented installation should come with clean lines and a clean coupling, and should be flushed through again straight afterwards.

Kegs are mostly filled with beers that are often served on tap, such as pils, witbier and a number of Belgian classics.

Small specialty beers often don’t come in kegs, because the production run is too small and a tapped keg has to be finished within a few days. For a party that means a choice: a wide range in bottles, or one or two fixed beers on tap.

Which connection a keg has differs per brewery. Check that before you rent an installation, because a wrong tap head will not fit.

A sealed keg keeps just like a bottle, but once it has been tapped the shelf life drops to a few days.

As long as the keg is closed, the beer is dark and airtight. A bottle lets light through, and how much depends on the colour of the glass. For long-term storage that is the biggest difference between the two.

After tapping, carbon dioxide is added and beer goes out. If a remainder is left, it loses its sparkle and deteriorates. For a party, therefore, plan on a keg that gets emptied.