Stout and porter are dark beers made using roasted
malt or barley, hops, water, and yeast. Stouts were traditionally the
generic term for the strongest or stoutest beers, typically 7% or 8%,
produced by a brewery.
Left: A pint of
Guinness with a slice of wheaten bread and butter.
Irish stout or dry stout (in Irish, leann
dubh, "black ale") is very dark or rich in colour and it often has a "toast"
or coffee-like taste. The most famous example, Guinness, is from Ireland. The
two other Irish dry stout breweries are Murphy's and Beamish. The alcoholic
content and "dry" flavour of a dry or Irish stout are both characterised as
light, although it varies from country to country.
Guinness is based on the porter style that originated in
London in the early 18th century and is one of the most successful beer brands
worldwide. A distinctive feature is the burnt flavour which is derived from the
use of roasted barley. For many years a portion of the drink was aged to give a
sharp lactic flavour, although Guinness has refused to confirm whether this
still occurs. The thick creamy head is the result of the beer being mixed with
nitrogen when being poured. It is popular with Irish people both in Ireland and
abroad and, in spite of a decline in consumption over recent years, is the
best-selling alcoholic drink of all time in Ireland.
Although Guinness may appear to be black, it is officially a
very dark shade of ruby.
A long time subject of bar conversations is the Guinness
cascade, where the gas bubbles appear to travel downwards in a pint glass of
Guinness. The effect is attributed to drag; bubbles that touch the walls of a
glass are slowed in their travel upwards. Bubbles in the centre of the glass
are, however, free to rise to the surface, and thus form a rising column of
bubbles. The rising bubbles create a current by the entrainment of the
surrounding fluid. As beer rises in the centre, the beer near the outside of the
glass falls. This downward flow pushes the bubbles near the glass towards the
bottom. Although the effect occurs in any liquid, it is particularly noticeable
in any dark nitrogen stout, as the drink combines dark-coloured liquid and