Draught (or Draft) beer is almost always un-pasteurized and therefore is more fragile. It should be consumed after being "tapped", and is generally truer to the flavors of the ingredients as pasteurization exposes the beer to heat and changes the flavor profile.

As draught beer is not pasteurized. It must be kept refrigerated between 35F. and 44F otherwise a beer will become wild, turn sour and cloudy in a day or two. Below 44F. a keg of draught beer should last 20-30 days before it loses it's fresh brewery taste and aroma. Craft beers (micro brews) tend to have a shorter shelf life and you should contact the brewery for their recommendations.

Keg Policies
We do not keep kegs in stock - they must be ordered in advance
What is available depends on when it is ordered. 
Generally 24 hours notice is preferred. 
Some products may be available on shorter notice, but please do not assume so. 

So what IS a (keg) barrel, anyway?
Size                                             ¼ Keg               ½ Keg
Gallon size                                      8                     16
12 oz cups served                          90                   180
When people say “keg”  they generally mean the ½

A barrel is a unit of measurement that equals 31 gallons.
A 1/2 barrel keg is what's known as a full-sized keg. It contains 16 gallons.
A 1/4 barrel keg is what's known as a half keg or "pony keg" and it holds 8 gallons.
1/6 barrel thus contains 5 gallons.

There are roughly 160 servings in one full-sized keg, based on 12-oz. glasses
There are 80 some servings in one pony keg (1/4 barrel), based on 12-oz. Cups
There are roughly 53 servings in a 1/6 barrel, based on regular 12 oz cups.

How much beer is in a beer keg?
Keg Size                     cases                          gallons                        weight
1/2 keg                        7                                  15.5                             170lb.
1/4 keg                        3 1/2                            7 3/4                            85lb.
1/6 keg                        2 1/2                            5                                  60lb.

Q:  What causes flat beer where the foamy head disappears quickly. Beer lacks usual zestful brewery fresh flavor.
A: Beer too cold  or loose tap connections.