This article is from the Real Ale FAQ, by with numerous contributions by Brett Laniosh others.
A: Field to Flush - Barley to Brain - Brewing & retailing in a nutshell
Probably the most important ingredient of beer is barley. This is Malted,
that is steeped in water to start germination, kept nice and warm to
continue germination, then toasted to stop germination before the seedling
has had time to use up the store of energy in the grain, but not before it
has converted it from starch (non soluble) to sugar (soluble). The sugar
is what yeast uses to make alcohol. Turn up the heat a bit more and some
of the sugar turns into toffee. This adds colouring and subtle taste to
the beer. Take water, treat it to make it fit for brewing, heat it to the
correct temperature, add crushed malt, leave awhile. Drain the liquid
(called wort pronounced "wurt") and rinse the malt (called "sparging") to
get as much of the sugar out as possible. Add some hops and boil. Hops
give bitterness and flowery hints to the brew. Traditionally, "hops" means
hop flowers as picked in the field. Often peleted hops are used instead.
This is a far more compact and convenient method of handling and storing
them but some subtleties are lost. A further development is hop oil.
Although this is ideal for modern process brewing it has a rather poor
reputation amongst drinkers.
Drain into a tank to cool then add yeast. The yeast will start fermenting
the sugars from the malted barley into alcohol and carbon dioxide. As it
does so it makes more yeast. Being a biological process the yeast likes to
have a go at doing other organic chemistry on the side. The effects are
small in comparison to the main activity of making alcohol but distinctive
flavours are created by the yeast. After the fermentation has died down,
filter off most of the yeast and leave to settle for a few days. Drain
into casks. Finings, a thick liquid, is added to each cask to make the
beer "polished". Some brews have extra hops added at this stage called
"dry hopping". Store for a week before dispatch to let the beer condition
in the cask. (If making keg beer then here you'd heat the beer to kill all
yeast, filter all yeast out, put in a keg then carbonate. (Definitely NOT
In days past most beer went on brewery owned drays from brewery direct to
pubs. This is still how a lot is delivered, but nowadays there are
wholesalers. Large ones do deals with brewers to make their beers
available in more outlets. These deals are often complex packages and are
concerned with bulk distribution and marketing. Smaller ones are more
concerned with obtaining beers from smaller breweries then transporting
them all over the country to supply free houses. All distribution chains
are a possible source of carelessness in caring for beer. Free-houses are
easily tempted by cheaper beer, but this may be from a poor supply route.