Tasting Exam (Fit for service)

A Master Sommelier once gave me some of the best advice that I've ever gotten about tasting wine, and I think it applies equally well to tasting beer. He told me:

Think long, think wrong.

At this point in the exam, you are in the home stretch. Don't second guess yourself just because you are tired.

Think about the beer you are going to be tasting - you are going to taste great beers. The exam isn't trying to trick you, so if a beer doesn't taste right, then something is wrong with it. 

It's your job to figure out what is wrong with the beer, if anything. Not all the beers will have problems, but many will. This section counts for half of the points in the tasting exam.
 

Don't wonder whether the tartness of a sour beer is hiding acetic acid from a dirty faucet. Don't wonder if the hop bitterness is masking infection. Don't think "maybe that's how its supposed to taste." 

If it tastes bad, then it is bad.

If the beer tastes bad, focus on why the beer tastes bad. 

It is important that you learn to tell the difference between a beer that you don't like and a beer that is faulty. 

Some faults occur during fermentation, and aren't the result of poor storage or dirty draft systems. Some faults are the direct result of poor storage or dirty draft systems.

Think about a draft system. The beer is in a keg, so it won't be lightstruck; however, it could acquire diacetyl from a dirty beer line, or it could contact acetobacter in the faucet, or it could have both!

If you decide that the beer is not fit to be served, be sure to give the probable cause for the fault.